[Clinical analysis in 15 pediatric patients with osteochondrodysplasias related to COMP gene variants]

Objective: To summarize the clinical and genetic characteristics of pseudoachondroplasia and multiple epiphyseal dysplasia caused by COMP gene variants in pediatric patients. Methods: This retrospective study concluded 15 pediatric patients with COMP-related pseudoachondroplasia and multiple epiphyseal dysplasia at Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine from July 2013 to August 2024. This paper analyzed clinical manifestations, laboratory findings and genetic testing. Results: This cohort comprised 15 pediatric patients (8 males and 7 females) with a diagnostic age of 5.3 (1.8,9.3) years. The major clinical presentations included abnormal gait (15/15), brachydactyly (11/15), genu varum (12/15), irregular metaphyseal changes (14/14) and epiphyseal dysplasia (14/14). Genetic analysis revealed 13 cases of pseudoachondroplasia and 2 multiple epiphyseal dysplasias cases associated with COMP gene variants. Fifteen variants were identified (8 pathogenic and 7 likely pathogenic), including 2 novel variants (c.1223A>G, c.1378G>C). Thirteen of these patients had variations clustered in exons 8-14 encoding the calmodulin-like domains, with c.1414_1419dupGACGAC emerging as a hotspot variant. Conclusions: COMP-related pseudoachondroplasia and multiple epiphyseal dysplasia predominantly manifest with gait abnormalities and skeletal deformities. COMP gene pathogenic variations were mainly located in calmodulin-like domains.