Affected infants and young boys are often shorter than their peers, but some catch up in height later in childhood or adolescence. Other physical differences associated with 49,XXXXY syndrome include abnormal fusion of certain bones in the forearm radioulnar synostosis , an unusually large range of joint movement hyperextensibility , elbow abnormalities, curved pinky fingers fifth finger clinodactyly , and flat feet pes planus. Affected individuals have distinctive facial features that can include widely spaced eyes ocular hypertelorism , outside corners of the eyes that point upward upslanting palpebral fissures , skin folds covering the inner corner of the eyes epicanthal folds , and a flat bridge of the nose.
Dental abnormalities are also common in this disorder. The penis is often short and underdeveloped, and the testes may be undescended, which means they are abnormally located inside the pelvis or abdomen.
The testes are small and do not produce enough testosterone, which is the hormone that directs male sexual development. The shortage of testosterone often leads to incomplete puberty.
Starting in adolescence, affected boys and men may have sparse body hair, and some experience breast enlargement gynecomastia. It is among the rarest of the sex chromosome disorders, which are conditions caused by changes in the number of sex chromosomes the X chromosome and the Y chromosome.
People typically have 46 chromosomes in each cell, two of which are the sex chromosomes. Boys and men with 49,XXXXY syndrome have the usual single Y chromosome, but they have four copies of the X chromosome, for a total of 49 chromosomes in each cell. The activity of these extra genes affects many aspects of development, including sexual development before birth and at puberty.
Researchers are working to determine which genes contribute to the specific developmental and physical differences that occur with 49,XXXXY syndrome. Boys and men with Klinefelter syndrome have one extra copy of the X chromosome, for a total of 47 chromosomes in each cell 47,XXY. People get one of each pair of chromosomes from their mother and one of each pair from their father.
The chromosomes that form the 23rd pair are called the sex chromosomes. They decide if a person is male or female. The chromosomes and genes have a special code called DNA. The order of the letters determines the information carried in each gene, like the way that a specific pattern of letters makes up the words in a sentence. Different people have different numbers of these CGG repeats, but most people have less than 45 repeats. People with FXS nearly always have more than repeats, many more than normal.
The number of CGG repeats that a person has can be determined by a blood test ordered by a healthcare provider or genetic counselor. People with different numbers of CGG repeats have different risks of developing fragile X-associated disorders and of having children with FXS. A female has two copies of the FMR1 gene, one on each of her two X chromosomes. The group a female is in normal, intermediate, premutation, or full mutation, as shown below is based on her FMR1 gene copy with the greatest number of CGG repeats.
A male has only one copy of the FMR1 gene on his only X chromosome, so the group a male is in is based on the number of CGG repeats in that one copy. This is considered a normal number of repeats. People with a normal number of repeats do not have FXS and do not pass a higher chance for having FXS to their children. Enlarged male breast.
Dislocated hips. Dislocation of hip. Wide-set eyes. Widely spaced eyes. Joints move beyond expected range of motion. Close sighted. Near sighted. Near sightedness. Flat feet. Flat foot. Fused forearm bones. Frequent respiratory infections. Multiple respiratory infections. Susceptibility to respiratory infections.
Smaller than typical growth of scrotum. Squint eyes. Upward slanting of the opening between the eyelids. Short and broad skull. Cleft roof of mouth. Depressed bridge of nose. Flat bridge of nose. Flat nasal bridge. Flat, nasal bridge. Flattened nasal bridge. Low nasal bridge. Low nasal root. Flat nose. Recessed nasal ridge.
Acid reflux. Acid reflux disease. Underdevelopment of part of brain called corpus callosum. Big lower jaw. Increased projection of lower jaw. Increased size of lower jaw. Large lower jaw. Prominent chin.
Prominent lower jaw. Blood clot in artery of lung. Decreased length of neck. Decreased body height. Small stature. Club feet. Club foot. Noninsulin-dependent diabetes. Type 2 diabetes. Type II diabetes. Blood clot in vein. Broad nose. Increased breadth of nose. Increased nasal breadth. Increased nasal width. Increased width of nose.
Do you have more information about symptoms of this disease? We want to hear from you. Do you have updated information on this disease? Cause Cause. If chromosomes don't separate correctly during cell division, one egg cell ultimately can retain all of the X chromosomes that would normally be placed into 4 separate egg cells during cell division.
If an egg cell containing four X chromosomes is fertilized by a normal male sperm with one Y chromosome , the resulting fertilized egg cell will be affected. The underlying reason for random errors in cell division is not known.
However, there is nothing a person can do, or not do, before or during pregnancy to cause 49,XXXXY syndrome to occur. The specific features of 49,XXXXY syndrome are thought result from increased "doses" of genes from the extra X chromosomes.
Treatment Treatment. Treatment depends on the symptoms present in each person and is often managed by a team of various specialists. Specialists involved in the care of an affected person may include heart doctors cardiologists , orthopedists , physiotherapists, speech therapists , eye doctors ophthalmologists , neurologists , and endocrinologists.
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