Also known as 49,XXXXY
What is 49,XXXXY syndrome?
49,XXXXY is a sex chromosome aneuploidy characterized XXXXY syndrome, also known as 49,XXXXY, is a rare sex chromosome aneuploidy in males characterized by congenital abnormalities (including heart and skeletal defects), intellectual disability, developmental delays, distinctive facial features, musculoskeletal abnormalities, and hypogonadism. Common symptoms include speech and language impairment, low muscle tone, short stature, musculoskeletal radioulnar synostosis, and genital anomalies, such as micropenis and undescended testes. Behavioral issues, including anxiety and irritability, are also frequently observed.
Who gets 49,XXXXY?
49,XXXXY is one of the rarest sex chromosome aneuploidies, estimated to affect approximately 1 in 85,000-100,000 males.
What causes 49,XXXXY?
49,XXXXY is caused by 3 extra X chromosome in boys, most commonly due to the presence of extra X chromosomes in the egg or in the sperm at the time of conception, resulting from nondisjunction (when chromosomes do not divide properly), and is not typically inherited.
How is 49,XXXXY diagnosed?
49,XXXXY is a chromosome condition which can be diagnosed from blood test. Tests that can diagnose 49,XXXXY include a karyotype (chromosome analysis looking at the number and structure of chromosomes in cells), a chromosomal microarray (a more detailed chromosome study looking for deletions or duplications across all chromosomes) or genetic sequencing (reading through the DNA sequence carried on the chromosomes). 49,XXXXY may be suspected based on physical or neurodevelopmental differences during childhood and can be identified before birth by prenatal screening and/or diagnostic testing, such as amniocentesis.
What is the treatment for 49,XXXXY?
Treatments for 49,XXXXY are specific to managing symptoms, including testosterone treatment beginning in adolescence to complete puberty and support bone health, infertility treatment by microTESE and ICSI, therapies for developmental delays, as well as neurodevelopmental, psychological and academic interventions.