PO Box 659
About XXYY Project
The XXYY Project was founded in 2003 and is a project of the Colorado Nonprofit Development Center, a 501(c)3 non-profit organization. Its mission is to build the capacity of parents and service providers to assist males with XXYY syndrome in leading purposeful, productive lives. The XXYY Project offers support groups, patient networking, and patient advocacy to affected individuals and families. XXYY syndrome is a genetic disorder in which males have an extra set of X&Y chromosomes leading to a range of medical and neurodevelopmental problems. Common medical problems include testosterone deficiency at puberty, low muscle tone, dental problems, tremor, and infertility. Developmental delays, learning disabilities, behavioral problems, ADHD, and autism spectrum disorders are some associated neurodevelopmental features.