Longitudinal deficiency of upper limb: similar case presentation of two subjects with unilateral ulnar hemimelia, carpal and metacarpal deficiency, and severe oligodactyly

Background: Longitudinal deficiency of upper limbs with oligodactyly is a very rare congenital malformation. It manifests itself as preaxial or postaxial hypoplasia/aplasia of long bones accompanied by reduction of palm and phalanges.

Objective: To report two cases with essentially similar phenotypic presentation characterized by unilateral mesomelic shortening of limb, ulnar hypoplasia, and severe deficiency of skeletal elements of hand that were found in unrelated individuals.

Methods: Review of clinical and family history, phenotypic examination, physical and radiological investigations, and literature review.

Results: In both individuals, the right arm was short, the size of the middle arm and hand being dramatically reduced in size, and the hand comprising only two functional digits. Roentgenograms revealed hemimelia/ dysmelia of the ulna, hypoplasia of radius, dysplastic distal radial head, and several missing carpals. Only two phalangeal rays were witnessed in the hand. Radiographic measurements showed a normal contralateral arm and lower limbs, and no other associated symptoms. These phenotypes were classified as type I and type D according to the schemes proposed by Swanson et al., and Ogino and Kato, respectively. Both individuals were the product of third degree consanguineous unions (F = 0.0625).

Conclusion: Consistent phenotypic pattern of longitudinal limb anomalies evident in two independent subjects suggest a common underlying genetic etiology. There is currently no known genetic factor to allow molecular testing and risk estimation for family members. Isolated limb anomalies may provide important clues to understand pathomorphogenetic mechanisms that lead to the disruption of normal limb development.