Snapshot A 24-year-old man with infertility is noted to have gynecomastia, atrophic testes, and azoospermia. Introduction Genetic disorder where male child is born with an extra, inactivated X chromosome (47 XXY) extra chromosome is known as a Barr body Epidemiology occurs in 1/1000 males 1/100 of those who are mentally retarded Presentation Symptoms breast development at puberty decreased intelligence inability to have children small testicles Physical exam female hair distribution gynecomastia long extremities azoospermia resulting in infertility testicular atrophy language development is slow child may be quiet and undemanding Evaluation Diagnosis is seldom made before puberty Testicular biopsy performed after puberty shows hyperplasia of the Leydig cells fibrosis of the seminiferous tubules Hormone levels gonadotrophins are increased testosterone is decreased Differential Double Y males (47XYY), Fragile X syndrome, Marfan syndrome Treatment Medical management testosterone replacement may deepen voice, increase muscle growth, and enhance sexual development may be helpful in assisting males with fertility Therapeutic management special education must be targeted at child's specific abilities often helpful to break larger objectives into smaller tasks speech therapy indicated to enhance language development physical therapy indicated to enhance muscle growth and strength behavioral therapy indicated to overcome shyness and enhance social interactions family therapy may be helpful to educate parents and siblings on needs of XXY children Prognosis, Prevention, and Complications Prognosis very good to excellent with appropriate medical management, education, and therapy Prevention no known preventive measures are available at this time Complications infertility