Atypical Smith-McCort dysplasia: A case report of skeletal dysplasia with cardiac anomaly

Smith-McCort dysplasia (SMC) is a rare autosomal recessive disease characterised by short-trunk dwarfism, skeletal dysplasia, and platyspondyly. It is closely related to Dyggve–Melchior–Clausen syndrome, but patients with SMC have normal mental functions. Both disorders are caused by mutations in the Dymeclin gene (DYM). We report the case of an 8-year-old girl presenting with disproportionate short stature, rhizomelic limb shortening, pectus carinatum, Harrison sulcus, and metaphyseal dysplastic changes in the knee, hip and shoulder joints. Genetic analysis identified a mutation in the DYM gene: Homozygous splice site variant (c.1126-2A>G). Notably, echocardiography revealed a small secundum atrial septal defect, a finding rarely associated with SMC.