Patients have short stature. Clinical features
involve head and neck (macrocephaly, short neck, hypertelorism, broad forehead,
down-slanted fissures, ptosis, puffy eyelids, triangular face, deeply
grooved or flat philtrum, excess nuchal skin, large ears, epicanthic folds),
musculoskeletal system (limited knee and ankle movement, pectus excavatum, scoliosis kyphosis),
central nervous system (CNS) (hypotonia, seizures, mental retardation), and heart (ectasia of coronary
arteries, pulmonary valve). Other features can include retroperitoneal or
visceral neurofibromata, ectopic testes, hypospadias, and inguinal hernia.