A previously unrecognized mental retardation malformation syndrome was observed in
five unrelated Japanese children. Consistent clinical features included moderate-to-severe
mental retardation, progressive dwarfism of postnatal onset, a peculiar facies characterized
by long palpebral fissures, with eversion of the lateral third of the lower eyelids,
arched eyebrows, broad and depressed nasal tip, large prominent earlobes, short fifth
fingers, abnormal dermatoglyphics including absence of digital triradius c or d, and
frequent otitis media in infancy. Inconsistent abnormalities included epicanthal folds,
cleft or high-arched palate, widely spaced teeth, low occipital hair line, scoliosis,
and dislocation of the hip joint. Neither familial occurrence nor parental consanguinity
was noted. The etiology of the malformation syndrome remains unknown.