Clinical and genetic characteristics and orthopedic manifestations of the Saul–Wilson syndrome in two Russian patients

Background. SaulWilson syndrome (SWS, microcephalic osteodysplastic dysplasia) is a rare genetic variant of skeletal dysplasia and is determined based on the modern classification for thin bone dysplasias. To date, 16 patients with SWS from different countries have been identified. Clinical cases. We presented the first description of the clinical and genetic characteristics of two Russian patients with SWS and compared them with published data. The main clinical manifestations of SWS are characterized by a combination of nanism and pathology of long tubular bones, spine, and eyes. Changes in the phenotype of patients in different age groups were analyzed. Discussion. In the analysis of the clinical manifestations of the observed patients and patients described in the literature, typical dysmorphic features of the face and radiographic data help in the diagnosis of SWS upon clinical examination. In the majority of the described patients, the nucleotide substitution c.1546GA is the major mutation in the gene responsible for SWS, which leads to the replacement of the amino acid Gly516Arg in the protein molecule. Conclusion. Based on the identified specific features of the phenotype of patients with SWS and the presence of a major mutation in the COG4 gene, a priority analysis of gene mutations is necessary. Orthopedic manifestations of SWS can lead to life-threatening conditions (cervical spine instability) and motor limitations (progressive osteoarthritis) and thus should be monitored dynamically.