Musculoskeletal Phenotypes of 19 Patients With X-Linked HNRNPH2-Related Neurodevelopmental Disorder: A Prospective Case Series.

Detailed clinical phenotypes have been previously reported for 33 individuals with X-linked HNRNPH2-related neurodevelopmental disorder. Of these, 75% self-reported a musculoskeletal abnormality, including hip dysplasia, scoliosis, kyphosis, lordosis, pes planus, arthritis, and missing spinous processes. Musculoskeletal phenotypes, screening recommendations, and treatment strategies have not been previously described. This case series presents a comprehensive overview of the musculoskeletal and orthopedic evaluations performed on 19 individuals diagnosed with X-linked HNRNPH2-related neurodevelopmental disorder (H2-RNDD). The evaluations cover standardized assessments of the spine, hips, knees, ankles, and feet. Physical exam findings and imaging results are described in detail. Pes planovalgus was noted in 17 (89%) individuals, restricted hip extension in 9 (47%), reduced ankle dorsiflexion in 7 (37%), scoliosis in 4 (21%), and hip subluxation in 4 (21%). By highlighting common musculoskeletal and orthopedic issues, this series aims to support timely recognition and provide recommendations for appropriate screening and treatment strategies.