(David W. Smith, 20th century, American paediatrician; Luc Lemli, 20th century, American paediatrician; John M. Opitz, 20th century, American paediatrician), syndrome with autosomal recessive inheritance in which children present with multiple congenital abnormalities in association with low birth weight and mental retardation. There is failure to thrive and progressive spasticity in childhood. Urogenital abnormalities with ambiguous genitalia may occur. Two forms are described: type I, which presents in childhood and type II, in which there may be intrauterine growth retardation.

Radiological manifestations are microcephaly, which may be associated with multiple other brain malformations, soft tissue syndactyly of the toes and nonspecific urinary tract abnormalities.