Cross-sectional, quantitative analysis of motor function in females with HNRNPH2-related disorder

To describe the gross motor function of individuals with HNRNPH2-related disorder (OMIM 300986, Mental Retardation, X-linked, Syndrome, Bain Type; MRXSB) and determine the associations between clinician-measured motor function and caregiver-reported mobility scores.

Developmental histories of 17 female participants with HNRNPH2-related disorder (mean age 11.2 years, range 2.7-37.1 years) with various genotypes within and adjacent to the nuclear localization sequence (NLS) were analyzed. Participants performed the Gross Motor Function Measure-88 (GMFM-88) and caregivers completed developmental histories and the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT).

All participants had measurable and quantifiable motor impairments. A strong positive correlation between the clinician-measured GMFM-88 total score and the caregiver-reported PEDI-CAT mobility domain score was established. Motor deficits were noted more often in individuals who were nonverbal. The 2 participants with genotypes adjacent to the NLS appear to have milder motor phenotypes.

The GMFM-88 and PEDI-CAT are useful and feasible measures of mobility in individuals with HNRNPH2-related disorders. Convergent validity was established between the clinician-measured GMFM-88 raw scores and caregiver-reported PEDI-CAT mobility domain scores. Factors including verbal status and genotype may impact motor abilities.