One of the sex chromosome variations least understood is XXYY. While the prevalence is reported to be 1 in 18,000 to 1 in 40,000, these estimates are likely an inadequate representation of true prevalence owing to missed diagnosis and alternate diagnoses for developmental, learning and behavioral issues. While early diagnosis is improving due to pre-natal screening and pre-natal diagnosis, there remains an unaccounted number of boys and men who have this variation and may not be aware.
For families with children and adults affected by XXYY, daily challenges abound in the areas of physical health, learning, behavior and launch to adulthood. Due to lack of information informed by research, no guidelines currently exist to help guide health care providers, educators and social services for how to preserve and maintain best function and quality of life for boys, men with XXYY and their families.