Tricorhinophalangeal Syndrome type 1: a novel variant and Perthes-like hip changes as first manifestation

We report a case of Trichorhinophalangeal syndrome type I (TRPS1) in a 16-year-old boy who was referred due to painless finger deformities over the last year. Legg-Calvé-Perthes disease (LGP) had been diagnosed at age 7 and required surgical treatment at age 12. Parents were healthy and non consanguineous; there was family history of pectus carinatum of maternal lineage. On examination the patient presented a bulbous nose, thin and sparse scalp hair; pectus carinatum; clinodactyly of the first and fifth fingers and hard painless swelling of all of the proximal interphalangeal joints; brachydactyly of the toes. Laboratory tests were unremarkable and radiographic studies revealed distinctive abnormalities of the hands (e.g., epiphyseal coning). This diagnosis was confirmed by gene sequencing, which identified in heterozygosity a pathogenic variant c.124G>T (p.Glu42Ter) in the exon 3 of the TRPS1 gene. The diagnosis of TRPS1 may be suspected upon identification of characteristic physical features, a compatible clinical history and imaging findings.