About 48,XXXY

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48,XXXY syndrome, also known as XXXY syndrome, is a less common X and Y chromosome condition, affecting between 1 in 17,000 and 1 in 50,000 male births. 48,XXXY is caused when nondisjunction errors occur in the development of the egg or sperm, resulting in a male inheriting two extra copies of the X chromosome.

48,XXXY is associated with a variety of symptoms, but not everyone has the same symptoms or at the same level. Symptoms of 48,XXXY may include:

  • Learning problems ranging from learning disabilities to intellectual disability
  • Delays and disorders in speech and language
  • Delays in motor skills like sitting, standing, and walking and motor coordination difficulties
  • Low muscle tone
  • Birth defects, more commonly cardiac, genital, or musculoskeletal systems
  • Distinctive physical features like wider-set eyes and curvature in pinky fingers
  • Irritability, outbursts, and temper tantrums
  • Anxiety
  • ADHD
  • Impaired social skills, social communication problems, autistic traits
  • Hypogonadism and infertility
  • Risk for gynecomastia
  • Average to taller height
  • Dental problems
  • Neurological problems such as seizures, tremors or motor tics
  • Allergies, asthma, and eczema
  • Hormone problems including hypothyroidism and diabetes
  • Strabismus
  • Sleep apnea
  • Gastrointestinal problems including reflux, constipation and eosinophilic esophagitis
  • Musculoskeletal problems including flat feet, radioulnar synostosis, scoliosis, osteoporosis
  • Risks for blood clots
  • Impaired adaptive skills


48,XXXY can be identified  during pregnancy via amniocentesis, CVS, or NIPS (screening test only). A diagnosis of 48,XXXY involves a special genetic test (commonly by blood after birth), typically either a karyotype or a microarray.  These tests can be ordered by most medical providers and are available through most major labs.


Facebook Support Groups: AXYS XXXY Global Support Group | 48,XXXY Medical Syndrome

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