It is genetic, but not hereditary. This means that while the genes of the parents cause the syndrome, there is a small chance of more than one child having the syndrome. The probability of inheriting the disease is about 1%.
The individuals with this syndrome are males, but a female version also exists with similar characteristics as the male version.
The mental effects of 49 XXXXY Syndrome vary, much like Down syndrome. Males with the syndrome tend to have impaired speech and behavioral problems. Those with 49 XXXXY syndrome tend to exhibit infantile secondary sex characteristics with sterility in adulthood and have some skeletal anomalies. Skeletal anomalies include:
The effects on the males also include: