A rare sex chromosome number anomaly disorder characterized genetically by the presence of an extra X and Y chromosome in males and clinically by tall stature dysfunctional testes associated with infertility and insufficient testosterone production cognitive affective and social functioning impairments global developmental delay and an increased risk of congenital malformations.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version April 2026
Newly diagnosed with
48,XXYY syndrome?
Our RARE Concierge Services Guides are available to assist you by providing information, resources and connections as you navigate your rare disease journey.
Advocacy Organizations
AXYS
AXYS, the Association for X and Y Chromosome Variations, is an advocacy, education and support organization for individuals with X and Y chromosome variations and their families. This includes those with Klinefelter syndrome (47,XXY), Trisomy X (47,XXX), 47,XYY, 48,XXYY, 48,XXXY and related genetic conditions. The mission of AXYS is to help individuals with one or more extra X and/or Y chromosomes
PPP2CA Pathways
PPP2CA Pathways connects families, shares strength, and supports the research community in the search for answers to Houge-Janssens Syndrome type 3.
Rare Chromosome Disorder Support Group – Unique
Through sharing knowledge and lived experience, Unique helps families and professionals navigate the world of chromosome and gene disorders
Don't see your organization here. Let us know here.
Clinical Trials
For a list of clinical trials in this disease area, please click here.