Nievergelt syndrome is characterized by specific deformities of the radius, ulna, tibia, and fibula. Radioulnar synostosis and a typical rhomboid shape of the tibia and fibula are observed. Nievergelt (1944) reported an affected man who transmitted the syndrome ... Nievergelt syndrome is characterized by specific deformities of the radius, ulna, tibia, and fibula. Radioulnar synostosis and a typical rhomboid shape of the tibia and fibula are observed. Nievergelt (1944) reported an affected man who transmitted the syndrome to 3 sons, each by a different wife. In a second family, 9 persons (2 males and 7 females) in 3 generations were affected, although perhaps with a different disorder. The x-ray changes, completely specific, are well demonstrated in the sporadic cases reported by Solonen and Sulamaa (1958). The characteristic rhomboidal shape of the tibia and fibula help differentiate this condition from the Grebe, or Brazilian, form of achondrogenesis (200700) and from recessive mesomelic dwarfism (249700). The cases called Nievergelt syndrome by Blockey and Lawrie (1963) were in fact instances of mesomelic dwarfism. Young and Wood (1974) described a typical sporadic case. Hess et al. (1978) restudied Nievergelt's family. Tuysuz et al. (2002) applied the diagnosis of Nievergelt syndrome to a 33-day-old boy who had short and thick tibiae, symmetrical oligosyndactyly of the hands, and distinctive face. In addition to the characteristic mesomelic limb anomalies of Nievergelt syndrome, this patient exhibited 2 additional features: agenesis of the cerebellar vermis and cataracts, both of which had not been previously associated with Nievergelt syndrome. Nakamura et al. (2007) described a father-son pair with a severe form of mesomelic dysplasia that shared many features of the Savarirayan (605274) and Nievergelt types. Radiographs of the son at 6 months of age showed mild mesomelic shortening of the arms with proximal radius hypoplasia and broadening of the distal radius and proximal ulna. The lower limbs showed greater involvement with markedly short, broad tibia and absent fibular ossification. Rudimentary distal ossification occurred with age. The father demonstrated identical abnormalities of the tibia and fibula but had broader radii and ulnae with interosseous bridging on the left. The triad of severely deformed tibia, rudimentary fibula, and mildly affected radius and ulna in the son resembled that of the Savarirayan type. The broad, trapezoidal radius in the father showed greater similarity to the Nievergelt type. Nakamura et al. (2007) suggested that the Savarirayan and Nievergelt types may be allelic autosomal dominant disorders.