Suspected association of a novel MECOM variant with congenital radioulnar synostosis: a case report

Congenital radioulnar synostosis (CRUS) is a forearm deformity caused by embryonic development disorder, characterized by limited forearm rotation, which can significantly impair patients' daily lives. The pathogenesis of CRUS has not been fully elucidated; with the advancement of whole-exome sequencing (WES) technology, a growing number of related gene mutations have been identified.

We report a 5-year-old boy who was diagnosed with CRUS due to bilateral limited forearm rotation. The boy was found to harbor a novel variant in the MECOM gene. His father had unilateral CRUS, while his mother was asymptomatic but carried the same gene mutation. The patient's paternal grandmother did not carry the aforementioned gene mutation. Eventually, the child underwent right ulnar-radial rotational osteotomy with internal fixation and left radial rotational osteotomy with external plaster fixation in our hospital, and his postoperative functional recovery was satisfactory. This report also provides a comprehensive review of the pathogenesis and clinical features of CRUS.

This study reports a novel variant site of the MECOM gene in a child with bilateral CRUS, which was inherited from his parents. This variant is putatively associated with bilateral CRUS, yet the definitive correlation awaits further verification via functional experiments and expanded cohort studies. It provides a potential candidate variant for the genetic profile of the disease and offers new insights for the etiological analysis of bilateral CRUS.