User:Mr. Ibrahem/Pentasomy X

Pentasomy X, also known as 49,XXXXX, is a chromosomal abnormality in which a female has five X chromosomes instead of the normal two. Signs may include intellectual disability, short height, low-set ears, decreased muscle tone, and developmental delay. Complications may include congenital heart disease.

The condition is due to problems during the formation of the reproductive cells in a person's parents. Risk factors include older parents at the time of conception. Diagnosis is suspected based on symptoms and confirmed by chromosomal analysis.

Treatment is based on symptoms. The condition is extremely rare, with less than forty reported cases as of 2011. The condition was first described in 1963.