Achondroplasia
Achondroplasia facts
What is achondroplasia?
Achondroplasia is a genetic (inherited) condition that results in abnormally short stature and is the most common cause of short stature with disproportionately short limbs. The average height of an adult with achondroplasia is 131 cm (52 inches, or 4 foot 4 inches) in males and 124 cm (49 inches, or 4 foot 1 inch) in females.
Although achondroplasia literally means "without cartilage formation," the defect in achondroplasia is not in forming cartilage but in converting it to bone, particularly in the long bones.
Achondroplasia is one of the oldest known birth defects. The frequency of achondroplasia is estimated to range from about 1 in 10,000 births in Latin America to about 12 in 77,000 in Denmark. An average figure worldwide is approximately 1 in 25,000 births.
What are the characteristics of achondroplasia?
Achondroplasia is a distinctive condition that usually can be noted at birth.
The diagnosis of achondroplasia can be based on the typical physical features, the hallmarks of achondroplasia, evident at birth. Characteristic features are also seen by X-rays, ultrasound, and other imaging techniques. With ultrasound imaging, the diagnosis can sometimes be strongly suspected before birth.
The molecular diagnosis of achondroplasia before birth is possible if there is suspicion of the diagnosis or an increased risk (such as when a parent is affected by achondroplasia). In families in which both parents have achondroplasia, prenatal diagnosis may be particularly useful, the aim being to distinguish fatal homozygous achondroplasia (with two copies of the defective gene) from heterozygous achondroplasia (with one copy of the achondroplasia gene) from normal. Diagnosis before birth is accomplished by examining cells obtained by chorionic villus sampling (CVS) or amniocentesis.
What can be done for patients with achondroplasia?
Children and adults with achondroplasia can lead normal lives provided they receive attentive, informed care by their physicians and parents. Considerations in monitoring children with achondroplasia include careful measurements of growth (length/height and weight) and head circumference using curves specially standardized for those with achondroplasia. Knowledgeable pediatric care and periodic orthopedic and neurologic examinations are critical.
When special problems complicate achondroplasia, prompt and expert intervention is important. For example:
Achondroplasia is inherited as an autosomal dominant trait whereby only a single copy of the abnormal gene (mutation) is required to cause achondroplasia. The gene for achondroplasia is fully penetrant, meaning that everyone who possesses it has achondroplasia. No one with the gene escapes achondroplasia. However, there is some variation in expression of the gene, meaning that children with achondroplasia are not carbon copies of each other, although they may look alike to the untutored eye.
In only about an eighth of cases is the gene inherited from a parent who has achondroplasia. Rather, about seven-eighths of cases are due to a new mutation (a new change in the gene). This means that most cases of achondroplasia occur sporadically (out of the blue) and are the result of a new mutation in a sperm or ovum of one of the normal- appearing parents. The chance of a new mutation rises with the age of the father. As early as 1912 it was noted that sporadic (new) cases were more often last-born than first-born children. This fits with the fact that the chance of an achondroplastic birth has been shown to increase with paternal age (age of the father).
What if someone with achondroplasia has children?
Although most children with achondroplasia do not have an achondroplastic parent but have a new mutant gene for achondroplasia, they can still transmit the gene to their children, and the risk for passing that gene down to a child is 50% in each pregnancy.
What if two people with achondroplasia have children?
People with achondroplasia sometimes have children together. If so, each parent has a 50:50 chance of passing on the gene. Thus, with each conception, there is a 25% chance for an average-size child, a 50% chance for a child (like them) with achondroplasia and a 25% chance for a conception with two achondroplasia genes. The combined presence of two genes for achondroplasia (called homozygous achondroplasia) causes a grievous skeletal disorder that leads to early death from breathing failure due to constriction by a tiny chest cage and neurologic problems from hydrocephalus.
What gene causes achondroplasia?
Achondroplasia is caused by mutations in the FGFR3 gene which codes for a protein (fibroblast growth factor receptor 3) that is important for the maintenance of bone and brain tissues. Two specific mutations in this gene are responsible for almost all cases of achondroplasia. These mutations limit the process of ossification, or the formation of bone from cartilage. The FGFR3 gene is located on the short (p) arm of chromosome 4 in chromosome band
- Achondroplasia is a genetic disorder of bone growth.
- Achondroplasia is the cause of the most common type of dwarfism (short-limbed disproportionate dwarfism)
- Achondroplasia is the most common cause of short stature with disproportionately short limbs.
- The appearance of the person with achondroplasia is characteristic.
- Intelligence is normal in people with achondroplasia.
- Complications of achondroplasia can affect the brain and the spinal cord.
- Achondroplasia is inherited as a dominant trait but 80% of cases are due to new mutations (neither parent has achondroplasia).
- Achondroplasia can be diagnosed before birth.
What is achondroplasia?
Achondroplasia is a genetic (inherited) condition that results in abnormally short stature and is the most common cause of short stature with disproportionately short limbs. The average height of an adult with achondroplasia is 131 cm (52 inches, or 4 foot 4 inches) in males and 124 cm (49 inches, or 4 foot 1 inch) in females.
Although achondroplasia literally means "without cartilage formation," the defect in achondroplasia is not in forming cartilage but in converting it to bone, particularly in the long bones.
Achondroplasia is one of the oldest known birth defects. The frequency of achondroplasia is estimated to range from about 1 in 10,000 births in Latin America to about 12 in 77,000 in Denmark. An average figure worldwide is approximately 1 in 25,000 births.
What are the characteristics of achondroplasia?
Achondroplasia is a distinctive condition that usually can be noted at birth.
- The baby with achondroplasia has a relatively long, narrow torso (trunk) with short extremities (arms and legs) and a disproportionate shortening of the proximal (near the torso) segments of the limbs (the upper arms and thighs).
- There is a typically large head with prominence of the forehead (frontal bossing), underdevelopment (hypoplasia) of the midface with cheekbones that lack prominence, and a low nasal bridge with narrow nasal passages.
- The baby's fingers appear short and the ring and middle fingers may diverge, giving the hand a trident (three-pronged) appearance. Most joints can extend more than normal. For example, the knees can hyperextend beyond the normal stopping point. Not all joints are lax in this way. To the contrary, extension and rotation of the elbow are abnormally limited. Hip extension also tends to be limited.
- At birth there is often prominence of the mid-to-lower back with a small gibbus (a hump). With walking, the hump goes away and a pronounced sway (lordosis) of the lumbar region (the lower back) becomes apparent. The lumbar lordosis is persistent into adulthood. The legs are bowed (genu varum).
- The baby exhibits some decrease in muscle tone (hypotonia). Because of the large head, especially compared to rest of the body, and the decreased muscle tone, the child with achondroplasia will run "behind schedule" in reaching the usual motor developmental milestones. The schedule to which an achondroplastic child's development should be compared is not that for all children in the general population, but rather the growth charts and timetable followed by children with achondroplasia.
- Intelligence is generally normal in patients with achondroplasia. Enlargement of the brain (megalencephaly) is common and normal with achondroplasia.
The diagnosis of achondroplasia can be based on the typical physical features, the hallmarks of achondroplasia, evident at birth. Characteristic features are also seen by X-rays, ultrasound, and other imaging techniques. With ultrasound imaging, the diagnosis can sometimes be strongly suspected before birth.
The molecular diagnosis of achondroplasia before birth is possible if there is suspicion of the diagnosis or an increased risk (such as when a parent is affected by achondroplasia). In families in which both parents have achondroplasia, prenatal diagnosis may be particularly useful, the aim being to distinguish fatal homozygous achondroplasia (with two copies of the defective gene) from heterozygous achondroplasia (with one copy of the achondroplasia gene) from normal. Diagnosis before birth is accomplished by examining cells obtained by chorionic villus sampling (CVS) or amniocentesis.
What can be done for patients with achondroplasia?
Children and adults with achondroplasia can lead normal lives provided they receive attentive, informed care by their physicians and parents. Considerations in monitoring children with achondroplasia include careful measurements of growth (length/height and weight) and head circumference using curves specially standardized for those with achondroplasia. Knowledgeable pediatric care and periodic orthopedic and neurologic examinations are critical.
When special problems complicate achondroplasia, prompt and expert intervention is important. For example:
- The foramen magnum (the large opening under the skull) may need to be surgically enlarged in cases of severe narrowing (stenosis) and compression of the spinal cord. When this opening is too narrow, the blood vessels and nerves are compressed, which can lead to central apnea (loss of breathing control). This is responsible for the risk of sudden death in infants (SIDS) with achondroplasia. The risk of sudden death for infants with achondroplasia is 2% to 5%.
- The back of individuals with achondroplasia can develop a marked sway (lordosis) to the lower back while abnormalities in the mid-back may cause a small hump (kyphosis) in infancy and compression of the spinal cord in adolescence. The spinal cord compression can require surgery to decompress it. Spinal stenosis is the most common medical complication of achondroplasia seen in adulthood.
- Orthopedic procedures may be performed for lengthening of the limb bones and correction of bowed legs (usually after full growth has been achieved).
- Surgery (lumbar laminectomy) is also indicated when spinal stenosis (narrowing) causes symptoms, which tends to be evident in young adults.
- Disproportion between the brain and the base of the skull can sometimes result in hydrocephalus ("water on the brain") which needs to be promptly detected and treated by placement of a shunt to drain the excess fluid.
- The large head with achondroplasia increases the chance of bleeding within the baby's head during vaginal delivery. This should be taken into account in planning the birth and postnatal care, and Cesarean delivery (C-section) may be recommended for a fetus with achondroplasia. The brainstem (which contains a center for controlling respiration) may be compressed in achondroplasia and contribute to abnormal breathing.
- Pregnant women with achondroplasia should have their babies delivered by cesarean section, due to their characteristically small pelvis, and high risk of birth related trauma.
- Middle ear infections (otitis media) are frequent and can lead to mild to moderate hearing loss. Therefore, ear infections should be readily suspected and promptly and fully treated with antibiotics and/or ear tubes.
- Dental crowding is also common. Teeth should be straightened and, if necessary, removed to alleviate this problem.
- Control of obesity is essential, and obesity can be a significant problem in people with achondroplasia. The excessive weight gain usually occurs during childhood. When obesity is present, the back and joint problems that are characteristic of this condition worsen in severity. The child with achondroplasia must not be allowed to become overweight. Adults with achondroplasia should also monitor and control their weight.
- Treatment with human growth hormone, which is still considered experimental, has been preliminarily reported to increase the growth rate after treatment, but studies have not yet demonstrated that adult height is increased by this treatment.
Achondroplasia is inherited as an autosomal dominant trait whereby only a single copy of the abnormal gene (mutation) is required to cause achondroplasia. The gene for achondroplasia is fully penetrant, meaning that everyone who possesses it has achondroplasia. No one with the gene escapes achondroplasia. However, there is some variation in expression of the gene, meaning that children with achondroplasia are not carbon copies of each other, although they may look alike to the untutored eye.
In only about an eighth of cases is the gene inherited from a parent who has achondroplasia. Rather, about seven-eighths of cases are due to a new mutation (a new change in the gene). This means that most cases of achondroplasia occur sporadically (out of the blue) and are the result of a new mutation in a sperm or ovum of one of the normal- appearing parents. The chance of a new mutation rises with the age of the father. As early as 1912 it was noted that sporadic (new) cases were more often last-born than first-born children. This fits with the fact that the chance of an achondroplastic birth has been shown to increase with paternal age (age of the father).
What if someone with achondroplasia has children?
Although most children with achondroplasia do not have an achondroplastic parent but have a new mutant gene for achondroplasia, they can still transmit the gene to their children, and the risk for passing that gene down to a child is 50% in each pregnancy.
What if two people with achondroplasia have children?
People with achondroplasia sometimes have children together. If so, each parent has a 50:50 chance of passing on the gene. Thus, with each conception, there is a 25% chance for an average-size child, a 50% chance for a child (like them) with achondroplasia and a 25% chance for a conception with two achondroplasia genes. The combined presence of two genes for achondroplasia (called homozygous achondroplasia) causes a grievous skeletal disorder that leads to early death from breathing failure due to constriction by a tiny chest cage and neurologic problems from hydrocephalus.
What gene causes achondroplasia?
Achondroplasia is caused by mutations in the FGFR3 gene which codes for a protein (fibroblast growth factor receptor 3) that is important for the maintenance of bone and brain tissues. Two specific mutations in this gene are responsible for almost all cases of achondroplasia. These mutations limit the process of ossification, or the formation of bone from cartilage. The FGFR3 gene is located on the short (p) arm of chromosome 4 in chromosome band
Angelman syndrome
- Angelman syndrome is a genetic disorder with characteristic features that include severe speech impairment, developmental delay, intellectual disability, and ataxia (problems with movement and balance).
- Angelman syndrome is named after the physician Harry Angelman who first delineated the syndrome in 1965.
- Angelman syndrome affects an estimated 1 in 12,000 to 20,000 people.
- Most children with Angelman syndrome have microcephaly (small head size) and epilepsy (recurrent seizures).
- The developmental delay of Angelman syndrome generally becomes noticeable by the age of 6 to 12 months.
- Adults with Angelman syndrome have facial features that are distinct and are often described as "coarse."
- Some of the characteristic features of Angelman syndrome are a result from the loss of function of a gene called UBE3A.
- The life expectancy for individuals with Angelman syndrome appears to be nearly normal.
What is Angelman Syndrome?
Angelman syndrome is a genetic disorder that primarily affects the nervous system that causes developmental delay and neurological problems. The physician Harry Angelman first delineated the syndrome in 1965, when he described several children in his practice as having "flat heads, jerky movements, protruding tongues, and bouts of laughter."
What are the characteristics, signs, and symptoms of Angelman syndrome?- nfants with Angelman syndrome appear normal at birth, but often have feeding problems in the first months of life and exhibit noticeable developmental delays by 6 to 12 months.
- Seizures often begin between 2 and 3 years of age.
- Speech impairment is pronounced, with little to no use of words. Individuals with this syndrome often display the following that can have severe functional deficits:
- hyperactivity,
- small head size,
- sleep disorders,
- movement and balance disorders
- Children with Angelman syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements.
- In addition to hyperactivity, a short attention span, and a fascination with water are common.
- With age, people with Angelman syndrome become less excitable, and the sleeping problems tend to improve. However, affected individuals continue to have intellectual disability, severe speech impairment, and seizures throughout their lives.
- Adults with Angelman syndrome have distinctive facial features that may be described as "coarse." Other common features include unusually fair skin with light-colored hair and an abnormal side-to-side curvature of the spine (scoliosis). The life expectancy of people with this condition appears to be nearly normal.
- Angelman syndrome results from absence of a functional copy of the UBE3A gene inherited from the mother.
Is there any treatment for Angelman syndrome? - There is no specific therapy for Angelman syndrome. Medical therapy for seizures is usually necessary. Physical and occupational therapies, communication therapy, and behavioral therapies are important in allowing individuals with Angelman syndrome to reach their maximum developmental potential.
What is the prognosis for Angelman syndrome?
Most individuals with Angelman syndrome will have severe developmental delays, speech limitations, and motor difficulties. However, individuals with Angelman syndrome can have normal life spans and generally do not show developmental regression as they age. Early diagnosis and tailored interventions and therapies help improve quality of life.
What research is being done on Angelman syndrome?
The NINDS supports and conducts research on neurogenetic disorders such as Angelman syndrome, to develop techniques to diagnose, treat, prevent, and ultimately cure them.
Turner syndrome
TURNER SYNDROME
What is Turner syndrome?
Turner syndrome is a chromosomal condition that alters development in females. Women with this condition tend to be shorter than average and are usually unable to conceive a child (infertile) because of an absence of ovarian function. Other features of this condition that can vary among women who have Turner syndrome include: extra skin on the neck (webbed neck), puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, heart defects and kidney problems.
This condition occurs in about 1 in 2,500 female births worldwide, but is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).
Turner syndrome is a chromosomal condition related to the X chromosome.
Researchers have not yet determined which genes on the X chromosome are responsible for most signs and symptoms of Turner syndrome. They have, however, identified one gene called SHOX that is important for bone development and growth. Missing one copy of this gene likely causes short stature and skeletal abnormalities in women with Turner syndrome
What are the symptoms for Turner syndrome?
Girls who have Turner syndrome are shorter than average. They often have normal height for the first three years of life, but then have a slow growth rate. At puberty they do not have the usual growth spurt.
Non-functioning ovaries are another symptom of Turner syndrome. Normally a girl's ovaries begin to produce sex hormones (estrogen and progesterone) at puberty. This does not happen in most girls who have Turner syndrome. They do not start their periods or develop breasts without hormone treatment at the age of puberty.
Even though many women who have Turner have non-functioning ovaries and are infertile, their vagina and womb are totally normal.
In early childhood, girls who have Turner syndrome may have frequent middle ear infections. Recurrent infections can lead to hearing loss in some cases.
Girls with Turner Syndrome are usually of normal intelligence with good verbal skills and reading skills. Some girls, however, have problems with math, memory skills and fine-finger movements.
Additional symptoms of Turner syndrome include the following:
Turner syndrome is not usually inherited in families. Turner syndrome occurs when one of the two X chromosomes normally found in women is missing or incomplete. Although the exact cause of Turner syndrome is not known, it appears to occur as a result of a random error during the formation of either the eggs or sperm.
Humans have 46 chromosomes, which contain all of a person's genes and DNA. Two of these chromosomes, the sex chromosomes, determine a person's gender. Both of the sex chromosomes in females are called X chromosomes. (This is written as XX.) Males have an X and a Y chromosome (written as XY). The two sex chromosomes help a person develop fertility and the sexual characteristics of their gender.
In Turner syndrome, the girl does not have the usual pair of two complete X chromosomes. The most common scenario is that the girl has only one X chromosome in her cells. Some girls with Turner syndrome do have two X chromosomes, but one of the X chromosomes is incomplete. In another scenario, the girl has some cells in her body with two X chromosomes, but other cells have only one. This is called mosaicism.
- Turner syndrome is a chromosomal condition related to the X chromosome that alters development in females, though it is not usually inherited in families.
- Symptoms of Turner syndrome are:
- short stature and non-functioning ovaries which causes infertility,
- some women may also have extra skin on the neck (webbed neck),
- puffiness or swelling (lymphedema) of the hands and feet,
- skeletal abnormalities,
- heart defects,
- high blood pressure,
- and kidney problems.
- Women who have Turner syndrome have a slightly higher risk of having an under active thyroid or developing diabetes.
- Many girls are diagnosed with Turner syndrome in early childhood when a slow growth rate and other features such as webbed neck, a broad chest, and widely spaced nipples are identified. Sometimes diagnosis is made at birth because of heart problems, an unusually wide neck, or swelling of the hands and feet.
- Treatment for Turner syndrome includes growth hormone injections and estrogen replacement therapy.
What is Turner syndrome?
Turner syndrome is a chromosomal condition that alters development in females. Women with this condition tend to be shorter than average and are usually unable to conceive a child (infertile) because of an absence of ovarian function. Other features of this condition that can vary among women who have Turner syndrome include: extra skin on the neck (webbed neck), puffiness or swelling (lymphedema) of the hands and feet, skeletal abnormalities, heart defects and kidney problems.
This condition occurs in about 1 in 2,500 female births worldwide, but is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).
Turner syndrome is a chromosomal condition related to the X chromosome.
Researchers have not yet determined which genes on the X chromosome are responsible for most signs and symptoms of Turner syndrome. They have, however, identified one gene called SHOX that is important for bone development and growth. Missing one copy of this gene likely causes short stature and skeletal abnormalities in women with Turner syndrome
What are the symptoms for Turner syndrome?
Girls who have Turner syndrome are shorter than average. They often have normal height for the first three years of life, but then have a slow growth rate. At puberty they do not have the usual growth spurt.
Non-functioning ovaries are another symptom of Turner syndrome. Normally a girl's ovaries begin to produce sex hormones (estrogen and progesterone) at puberty. This does not happen in most girls who have Turner syndrome. They do not start their periods or develop breasts without hormone treatment at the age of puberty.
Even though many women who have Turner have non-functioning ovaries and are infertile, their vagina and womb are totally normal.
In early childhood, girls who have Turner syndrome may have frequent middle ear infections. Recurrent infections can lead to hearing loss in some cases.
Girls with Turner Syndrome are usually of normal intelligence with good verbal skills and reading skills. Some girls, however, have problems with math, memory skills and fine-finger movements.
Additional symptoms of Turner syndrome include the following:
- An especially wide neck (webbed neck) and a low or indistinct hairline.
- A broad chest and widely spaced nipples.
- Arms that turn out slightly at the elbow.
- A heart murmur, sometimes associated with narrowing of the aorta (blood vessel exiting the heart).
- A tendency to develop high blood pressure (so this should be checked regularly).
- Minor eye problems that are corrected by glasses.
- Scoliosis (deformity of the spine) occurs in 10 percent of adolescent girls who have Turner syndrome.
- The thyroid gland becomes under-active in about 10 percent of women who have Turner syndrome. Regular blood tests are necessary to detect it early and if necessary treat with thyroid replacement.
- Older or over-weight women with Turner syndrome are slightly more at risk of developing diabetes.
- Osteoporosis can develop because of a lack of estrogen, but this can largely be prevented by taking hormone replacement therapy.
Turner syndrome is not usually inherited in families. Turner syndrome occurs when one of the two X chromosomes normally found in women is missing or incomplete. Although the exact cause of Turner syndrome is not known, it appears to occur as a result of a random error during the formation of either the eggs or sperm.
Humans have 46 chromosomes, which contain all of a person's genes and DNA. Two of these chromosomes, the sex chromosomes, determine a person's gender. Both of the sex chromosomes in females are called X chromosomes. (This is written as XX.) Males have an X and a Y chromosome (written as XY). The two sex chromosomes help a person develop fertility and the sexual characteristics of their gender.
In Turner syndrome, the girl does not have the usual pair of two complete X chromosomes. The most common scenario is that the girl has only one X chromosome in her cells. Some girls with Turner syndrome do have two X chromosomes, but one of the X chromosomes is incomplete. In another scenario, the girl has some cells in her body with two X chromosomes, but other cells have only one. This is called mosaicism.
ILLUSTRATION:
Frequency :
This condition occurs in about 1 in 2,500 newborn girls worldwide, but it is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).
SOURCE:https://ghr.nlm.nih.gov/condition/turner-syndrome#statistics
This condition occurs in about 1 in 2,500 newborn girls worldwide, but it is much more common among pregnancies that do not survive to term (miscarriages and stillbirths).
SOURCE:https://ghr.nlm.nih.gov/condition/turner-syndrome#statistics
- Inheretance Pattern:
- Most cases of Turner syndrome are not inherited. When this condition results from monosomy X, the chromosomal abnormality occurs as a random event during the formation of reproductive cells (eggs and sperm) in the affected person's parent. An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may lose a sex chromosome as a result of nondisjunction. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have a single X chromosome in each cell and will be missing the other sex chromosome.
- Mosaic Turner syndrome is also not inherited. In an affected individual, it occurs as a random event during cell division in early fetal development. As a result, some of an affected person's cells have the usual two sex chromosomes, and other cells have only one copy of the X chromosome. Other sex chromosome abnormalities are also possible in females with X chromosomemosaicism.
- Rarely, Turner syndrome caused by a partial deletion of the X chromosome can be passed from one generation to the next.
SOURCE:https://ghr.nlm.nih.gov/condition/turner-syndrome#inheritance
GENETIC CHANGES:
SOURCE:https://ghr.nlm.nih.gov/condition/turner-syndrome#genes
- Turner syndrome is related to the X chromosome, which is one of the two sexchromosomes. People typically have two sex chromosomes in each cell: females have two X chromosomes, while males have one X chromosome and one Y chromosome. Turner syndrome results when one normal X chromosomeis present in a female's cells and the other sex chromosome is missing or structurally altered. The missing genetic material affects development before and after birth.
- About half of individuals with Turner syndrome have monosomy X, which means each cell in the individual's body has only one copy of the X chromosome instead of the usual two sex chromosomes. Turner syndrome can also occur if one of the sex chromosomes is partially missing or rearranged rather than completely absent. Some women with Turner syndrome have a chromosomal change in only some of their cells, which is known as mosaicism. Women with Turner syndrome caused by X chromosome mosaicism are said to have mosaic Turner syndrome.
- Researchers have not determined which genes on the X chromosome are associated with most of the features of Turner syndrome. They have, however, identified one gene called SHOX that is important for bone development and growth. The loss of one copy of this gene likely causes short stature and skeletal abnormalities in women with Turner syndrome.
SOURCE:https://ghr.nlm.nih.gov/condition/turner-syndrome#genes
Diagnosis and Management:
Source :https://ghr.nlm.nih.gov/condition/turner-syndrome#diagnosis
- Prenatal
- 45,X karyotype, showing an unpaired X at the lower rightTurner syndrome may be diagnosed by amniocentesis or chorionic villus samplingduring pregnancy.
- Usually, fetuses with Turner syndrome can be identified by abnormal ultrasoundfindings (i.e., heart defect, kidney abnormality, cystic hygroma, ascites). In a study of 19 European registries, 67.2% of prenatally diagnosed cases of Turner Syndrome were detected by abnormalities on ultrasound. 69.1% of cases had one anomaly present, and 30.9% had two or more anomalies.
- An increased risk of Turner syndrome may also be indicated by abnormal triple or quadruple maternal serum screen. The fetuses diagnosed through positive maternal serum screening are more often found to have a mosaic karyotype than those diagnosed based on ultrasonographic abnormalities, and conversely, those with mosaic karyotypes are less likely to have associated ultrasound abnormalities.
- Although the recurrence risk is not increased, genetic counseling is often recommended for families who have had a pregnancy or child with Turner syndrome.
- PostnatalTurner syndrome can be diagnosed postnatally at any age. Often, it is diagnosed at birth due to heart problems, an unusually wide neck or swelling of the hands and feet. However, it is also common for it to go undiagnosed for several years, typically until the girl reaches the age of puberty/adolescence and she fails to develop properly (the changes associated with puberty do not occur). In childhood, a short stature can be indicative of Turner syndrome.
- A test called a karyotype, also known as a chromosome analysis, analyzes the chromosomal composition of the individual. This is the test of choice to diagnose Turner syndrome.
Source :https://ghr.nlm.nih.gov/condition/turner-syndrome#diagnosis
Skin cancer:
DEFINITION:
SOURCE:http://www.mayoclinic.org/diseases-conditions/skin-cancer/basics/definition/con-20031606
- Skin cancer — the abnormal growth of skin cells — most often develops on skin exposed to the sun. But this common form of cancer can also occur on areas of your skin not ordinarily exposed to sunlight.
- There are three major types of skin cancer — basal cell carcinoma, squamous cell carcinoma and melanoma.
- You can reduce your risk of skin cancer by limiting or avoiding exposure to ultraviolet (UV) radiation. Checking your skin for suspicious changes can help detect skin cancer at its earliest stages. Early detection of skin cancer gives you the greatest chance for successful skin cancer treatment.
SOURCE:http://www.mayoclinic.org/diseases-conditions/skin-cancer/basics/definition/con-20031606
ILLUSTRATION:
Frequency:
SOURCE: https://www.aad.org/media/stats/conditions/skin-cancer
- Skin cancer is the most common cancer in the United States.
- Current estimates are that one in five Americans will develop skin cancer in their lifetime.
- It is estimated that more than 8,500 people in the U.S. are diagnosed with skin cancer every day.
- Researchers estimate that 5.4 million cases of nonmelanoma skin cancer, including basal cell carcinoma and squamous cell carcinoma, were diagnosed in 3.3 million people in the United States in 2012.5
- It is estimated that 161,790 new cases of melanoma, 74,680 noninvasive (in situ) and 87,110 invasive, will be diagnosed in the U.S. in 2017.6-7
- Invasive melanoma is projected to be the fifth most common cancer for men (52,170 cases) and the sixth most common cancer for women (34,940 cases) in 2017.
- Melanoma rates in the United States doubled from 1982 to 2011.1
- Caucasians and men older than 50 have a higher risk of developing melanoma than the general population.6-8
- The incidence in men ages 80 and older is three times higher than women of the same age.6
- The annual incidence rate of melanoma in non-Hispanic Caucasians is 26 per 100,000, compared to 5 per 100,000 in Hispanics and 1 per 100,000 in African-Americans.6
- In people of color, melanoma is often diagnosed at later stages, when the disease is more advanced.9
- Before age 50, melanoma incidence rates are higher in women than in men, but by age 65, rates are twice as high in men.6
- Melanoma in Caucasian women younger than 44 has increased 6.1 percent annually, which may reflect recent trends in indoor tanning.8
- Melanoma is the second most common form of cancer in females age 15-29.10
- Melanoma is increasing faster in females age 15-29 than in males of the same age group.9
SOURCE: https://www.aad.org/media/stats/conditions/skin-cancer
Symptoms:
- Skin cancer develops primarily on areas of sun-exposed skin, including the scalp, face, lips, ears, neck, chest, arms and hands, and on the legs in women. But it can also form on areas that rarely see the light of day — your palms, beneath your fingernails or toenails, and your genital area.
- Skin cancer affects people of all skin tones, including those with darker complexions. When melanoma occurs in people with dark skin tones, it's more likely to occur in areas not normally exposed to the sun, such as the palms of the hands and soles of the feet.
Diagnosis:
SOURCE:http: //www.mayoclinic.org/diseases-conditions/skin-cancer/basics/tests-diagnosis/con-20031606
- Examine your skin. Your doctor may look at your skin to determine whether your skin changes are likely to be skin cancer. Further testing may be needed to confirm that diagnosis.
- Remove a sample of suspicious skin for testing (skin biopsy). Your doctor may remove the suspicious-looking skin for lab testing. A biopsy can determine whether you have skin cancer and, if so, what type of skin cancer you have.
SOURCE:http: //www.mayoclinic.org/diseases-conditions/skin-cancer/basics/tests-diagnosis/con-20031606
Prognosis:
- Five-year survival for malignant melanoma generally decreases with increasing age. Five-year net survival in men ranges from 91% in 15-39 year-olds to 82% in 80-99 year-olds for patients diagnosed with malignant melanoma in England during 2009-2013.[1] In women, five-year survival ranges from 97% to 84% in the same age groups.
Prevention:
Most skin cancers are preventable. To protect yourself, follow these skin cancer prevention tips:
Source: http://www.mayoclinic.org/diseases-conditions/skin-cancer/basics/prevention/con-20031606
Most skin cancers are preventable. To protect yourself, follow these skin cancer prevention tips:
- Avoid the sun during the middle of the day. For many people in North America, the sun's rays are strongest between about 10 a.m. and 4 p.m. Schedule outdoor activities for other times of the day, even in winter or when the sky is cloudy.
You absorb UV radiation year-round, and clouds offer little protection from damaging rays. Avoiding the sun at its strongest helps you avoid the sunburns and suntans that cause skin damage and increase your risk of developing skin cancer. Sun exposure accumulated over time also may cause skin cancer. - Wear sunscreen year-round. Sunscreens don't filter out all harmful UV radiation, especially the radiation that can lead to melanoma. But they play a major role in an overall sun protection program.
Use a broad-spectrum sunscreen with an SPF of at least 15. Apply sunscreen generously, and reapply every two hours — or more often if you're swimming or perspiring. Use a generous amount of sunscreen on all exposed skin, including your lips, the tips of your ears, and the backs of your hands and neck. - Wear protective clothing. Sunscreens don't provide complete protection from UV rays. So cover your skin with dark, tightly woven clothing that covers your arms and legs, and a broad-brimmed hat, which provides more protection than a baseball cap or visor does.
Some companies also sell photoprotective clothing. A dermatologist can recommend an appropriate brand.
Don't forget sunglasses. Look for those that block both types of UV radiation — UVA and UVB rays. - Avoid tanning beds. Lights used in tanning beds emit UV rays and can increase your risk of skin cancer.
- Be aware of sun-sensitizing medications. Some common prescription and over-the-counter drugs, including antibiotics, can make your skin more sensitive to sunlight.
Ask your doctor or pharmacist about the side effects of any medications you take. If they increase your sensitivity to sunlight, take extra precautions to stay out of the sun in order to protect your skin. - Check your skin regularly and report changes to your doctor. Examine your skin often for new skin growths or changes in existing moles, freckles, bumps and birthmarks.
With the help of mirrors, check your face, neck, ears and scalp. Examine your chest and trunk, and the tops and undersides of your arms and hands. Examine both the front and back of your legs, and your feet, including the soles and the spaces between your toes. Also check your genital area and between your buttocks.
Source: http://www.mayoclinic.org/diseases-conditions/skin-cancer/basics/prevention/con-20031606