XXXY syndrome

XXXY syndrome(s)

XXXXY syndrome A group of chromosome defects with multiple X chromosomes and one Y chromosome Clinical Somatic defects overlap Klinefelter syndrome–small undescended testes, hypoplastic penis, gynecomastia, mental retardation, wide-set eyes, ulnar and radial abnormalities; >¹⁄₂ of those with the 49, XXXXY syndrome present with low birth weight, muscle hypotonicity, profound mental and growth retardation, malformed ears, a short neck, hypertelorism with a mongoloid slant, flattened nose, hypoplastic external male genitalia, clinodactyly, radioulnar synostoses, coxa vara, genu varum, pes planus Treatment None, testosterone may improve 2º sexual characteristics