Exploring EPHB4 in gait disorders: VUS detection and phenotypic characterization in a toe-walking cohort.

BACKGROUND

Idiopathic toe walking (ITW) is a gait abnormality with a suspected genetic contribution, although its underlying mechanisms remain poorly understood. While ephrin type-B receptor 4 (EPHB4) is primarily recognized for its role in vascular development, this study explored whether EPHB4 variants identified in children with ITW were associated with specific clinical characteristics.

METHODS

We retrospectively analyzed the clinical and genetic data of 20 children with toe walking who harbored EPHB4 variants identified using a targeted 49-gene next-generation sequencing (NGS) panel.

RESULTS

Genetic analysis identified 18 distinct EPHB4 variants, all of which were classified as variants of uncertain significance (VUS) according to the five-tier sequence variant classification system. The most common clinical findings were pes cavus (40%), clinodactyly/brachydactyly (40%), and speech or language delay (40%). Notably, only 10% of patients exhibited the venous anomalies typically associated with pathogenic EPHB4 variants.

CONCLUSIONS

This study identified a recurrent occurrence of EPHB4 variants in children with idiopathic toe walking. However, these findings should be interpreted with caution because all identified variants were classified as VUS, no clear genotype-phenotype correlation was observed, and ascertainment bias cannot be excluded. Further functional studies and familial segregation analyses are required to determine whether these findings represent a true biological association or incidental observations. These results highlight the complexity of investigating potential genetic contributors to common pediatric gait disorders such as idiopathic toe walking.

CLINICAL TRIAL REGISTRATION: not applicable.Retrospective cohort analysis of existing clinical data. Not prospectively registered as no interventions were performed.