48XXYY Syndrome

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Boys normally have 46 chromosomes in each of their cells, but boys with 48XXYY syndrome have an extra X and and an extra Y chromosome, one from their mother, one from their father, so they have 48 chromosomes. The main effect of this is to disrupt male sexual development.

This condition affects 1 in 18,000 to 50,000 boys. Each child has a different range of the  symptoms listed below. Many of these symptoms first start to appear in adolescence. Boys might be misdiagnosed with conditions such as autistim, bi-polar disorder or Fragile X syndrome. Some boys might display some of the following symptoms and not have 48XXYY at all.

Physical symptoms include tall stature for their age, hand tremor, leg ulcers, elbow abnormalities, curvature of the little finger (known as ‘clindactyly’), stretchy joints (known as ‘hypermobility’), curvature of the spine (known as ‘scoliosis’), significant dental problems, flat feet, low muscle tone, low or no testosterone. Young children be might to slow to crawl or walk or have difficulty picking things up.

Neurological and mental symptoms include developmental delays, speech impairment, behavioral issues, social communication disorders, anxiety disorders, depression, learning disability, infertility, mood swings and outbursts and autism spectrum disorders.

Contact other families affected by 48XXYY Syndrome


A geneticist will use a High Resolution Chromosome test for 48XXYY.


There is no cure for 48XXYY syndrome but medication and therapies can be used to reduce the effects of symptoms.

Genetic Inheritence

This condition is not inherited. It usually occurs randomly during the formation of reproductive cells (eggs and sperm). 

Contact other families affected by 48XXYY Syndrome

We will try to put you in touch with other families affected by 48XXYY Syndrome. Fill in the form below and a member of our support team will get back to you within 7 working days.

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