Introduction:
Males have 46 chromosomes, including two copies of each chromosome from 1 to 22, and an X and a Y sex chromosome. This is referred to as 46, XY (44 numbered chromosomes and two sex chromosomes). Three extra X chromosomes are present in males with 49, XXXXY syndrome, thus giving a total of 49 chromosomes. Compared to other syndromes where males have more X chromosomes than expected, 49, XXXXY syndrome occurrence is rare.
What Is 49, XXXXY Syndrome?
Three extra X chromosomes are present in males with 49, XXXXY syndrome, a type of chromosome abnormality. However, 49, XXXXY syndrome has many characteristics in common with Klinefelter syndrome (XXXY syndrome) and is more severe. Therefore, this syndrome is occasionally referred to as a variant of Klinefelter syndrome. 49, XXXXY syndrome affects about 1 in every 85,000 to 100,000 males. It was first identified in 1960. However, the signs and symptoms of 49, XXXXY syndrome can vary depending on the individual.
Many aspects of development are influenced by the activity of these extra genes, including sexual development before birth and during puberty. Researchers are trying to determine which genes are responsible for the specific developmental and physical differences in the 49, XXXXY syndrome.
What Are the Other Names of This Condition?
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49, XXXXY chromosome anomaly.
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XXXXY aneuploidy.
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Chromosome XXXXY syndrome.
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XXXXY syndrome.
What Causes 49, XXXXY Syndrome?
Extra copies of multiple genes are seen in the X chromosome of men with 49, XXXXY syndrome. This syndrome is caused by maternal nondisjunction during meiosis I and II (cell division). An error known as non-disjunction prevents the distribution of X chromosomes among developing egg cells during cell division. Normally, each egg cell receives a single X chromosome during cell division. However, due to nondisjunction, a single egg cell may end up with four X chromosomes instead of the normal distribution of four X chromosomes among four different egg cells. The resultant child will have four X chromosomes and one Y chromosome (49, XXXXY) in each of the body's cells if a sperm cell with a single Y chromosome fertilizes this egg cell.
How 49, XXXXY Syndrome Is Inherited?
49, XXXXY syndrome is not inherited; it develops as a result of random changes that occur in the mother of an affected person during the development of reproductive cells (eggs). It is a genetic but not a hereditary condition, which means that while the parents' genes cause the syndrome, there is only a small chance that more than one child will have the syndrome. The likelihood of inheriting the disease is nearly 1 %.
What Are the Symptoms Associated With 49, XXXXY Syndrome?
The symptoms associated with 49, XXXXY syndrome are similar to Klinefelter syndrome and 48, XXXY syndrome, but they are usually much more severe.
The symptoms associated with 49, XXXXY syndrome are the following.
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Hypotonia (poor muscle tone).
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Carious teeth.
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Azoospermia (absence of sperm in semen).
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Decreased testicular size.
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Intellectual disability.
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Abnormal epiphysis morphology.
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Attention deficit hyperactivity disorder.
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Wide nose.
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Mandibular prognathia.
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Developmental delay.
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Hypoplasia of the penis.
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Chronic otitis media.
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Short stature.
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Irritability.
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Gastroesophageal reflux.
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Brachycephaly (short, flattened skull).
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Small scrotum.
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Scoliosis.
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Joint hyper flexibility.
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Gynecomastia.
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Abnormal enamel morphology.
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Infertility.
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Language impairment.
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Hip dislocation.
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Seizure.
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Pulmonary embolism.
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Tremor.
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Shyness.
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Low frustration tolerance.
How Does the 49, XXXXY Syndrome Affect Male Fertility?
49, XXXXY syndrome interferes with male sexual development. The penis is frequently short and underdeveloped, and the testicles may be undescended, which means they are abnormally positioned inside the pelvis or abdomen. Male sexual development is regulated by testosterone, which is not produced in sufficient amounts by the small and underdeveloped testes. Incomplete puberty is frequently caused by testosterone deficiency. The affected individuals may start losing their body hair in adolescence, and some may develop enlarged breasts (gynecomastia). All men with 49, XXXXY syndrome, are infertile because their testes do not produce sperm.
What Are the Diagnostic Tests Used for 49, XXXXY Syndrome?
Diagnosis of 49, XXXXY syndrome can be made based on the clinical symptoms. Once the symptoms are identified, karyotyping can be used to confirm the diagnosis of 49, XXXXY. A karyotype is the overall appearance of an individual organism's chromosomes in cells. Karyotyping involves counting the number of chromosomes in a person's body as well as any abnormalities to determine their chromosome complement.
What Are the Treatment Options Available for 49, XXXXY Syndrome?
There is no specific treatment available to correct the genetic abnormality associated with 49, XXXXY syndrome. The only possibility is the treatment of the symptoms. The majority of the symptoms associated with 49, XXXXY can be managed with proper medical treatment.
Conclusion:
49, XXXXY syndrome is a rare sex chromosomal disorder that affects males. It is characterized by the presence of an extra X chromosome in males. It is similar to Klinefelter syndrome but more severe. The symptoms associated with this syndrome include learning disabilities or intellectual disability, low muscle tone, hypogonadism, infertility, delayed growth, distinctive facial features, and various congenital disabilities that may affect the heart, bones, brain, or kidneys. Most of the time, a random error in cell division causes it.
