Werner mesomelic dysplasia

Abstract

Introduction. The term “mesomelic dysplasia” refers to a group of disorders wherein limb shortening is most pronounced in the middle segment (forearm and leg) of the extremities. Werner mesomelic dysplasia is characterized by absence or hypoplasia of the tibia, preaxial polysyndactyly on the hands and feet, as well as by triphalangeal thumbs, absence of a patella, and fibular bone dislocation. Molecular genetic causes of the disease are mutations at position 404 of the regulatory element (ZRS) of the SHH gene in the LMBR1 gene (OMIM 188740). Clinical case. A girl with triphalangeal thumbs and polydactyly of the hands, right hip dislocation, tibia hypoplasia, fibular dislocation on both sides, and preaxial polydactyly of the feet was examined and treated at the age of 1 year. Considering the clinical and radiological picture, the girl was diagnosed with Werner mesomelic dysplasia. To verify the disease, a molecular genetic examination of the child was performed. A variant of replacement of 230 T > C in the regulatory element of the ZRS of the SHH gene was discovered in the literature. Discussion. Differential diagnosis can be made with Laurin-Sandrow syndrome, which is characterized by doubling of the ulna and fibula with the absence of the radius and tibia and preaxial polydactyly/syndactyly of the hands and feet. The presence of nasal defects (particularly involving the columella) distinguishes this condition from other syndromes, which was not shown in this clinical observation. Conclusion. We report the clinical case of an autosomal-dominant disease, Werner mesomelic dysplasia, which is a rare pathology with a typical clinical picture combined with congenital hip dislocation, which was not previously described. The molecular genetic examination confirms the presence of a pathogenic variant of the ZRS element of the SHH gene, which causes the development of Werner’s mesomelic dysplasia, but the mutation variant was not registered before, which requires an additional examination of the child’s relatives.