Since the description by de la Chapelle and colleagues of two sibs with a unique skeletal dysplasia, two additional cases have occurred, one in the original Finish family and one sporadic patient born to unrelated parents of Belgian descent. The original Finnish family has later had a fourth child, a normal daughter who was found to be unaffected upon radiographic examination in the 19th week of gestation. These additional findings are compatible with recessive inheritance. Physical features common to these four patients include cleft palate, small thorax, moderately severe micromelia with small hands, and equinovarus deformity. In each case, the ulnae and fibulae were reduced to an almost triangular osseous remnant. Other long bones were short and bowel. Neonatal death occurred in all cases and may be attributed to a consistent triad of respiratory tract malformations: laryngeal stenosis, tracheobronchomalacia, and pulmonary hypoplasia. Clinical and radiographic features are sufficiently unique to distinguish de la Chapelle dysplasia from other disorders in the spectrum of neonatal lethal osteochondrodysplasias. Lacunar halos were identified as a distinctive histopathologic feature also observed in achondrogenesis but not in several other skeletal dysplasias.