Phenotype of the index patients with WARBM1. (A) Pedigree. (B) Pictures of the index patients illustrating severe dystrophy, microcephaly, and distal contractures. Facial features include a prominent nasal root, relatively short nose, large ears, and a mild facial hypertrichosis. (C) Appropriate skeletal age but severe osteopenia on conventional X-rays of left hand of patient IV.2 when compared to an age- and sex-matched control. (D-G) Cranial MRI of patient IV.2 revealed parietal pachygyria (D, axial T2), widened sylvian fissure (E, axial T2), cerebellar atrophy (F, coronal T2), and corpus callosum dysmorphism with agenesis of the splenium corpi (G, sagittal T2). (H) Scheme depicts all previously reported mutations in the RAB3GAP1 gene in patients with WARBM1 and the novel deletion in our index patients.