Mutation in the X-linked RAB40AL gene (Martin-Probst syndrome) with mental retardation, sensorineural hearing loss, and anomalies of the craniofacies and genitourinary tract: a second case report

An X-linked neurodevelopmental disorder previously had been reported in only one family, associated with a p.D59G mutation in the RAB40AL gene that encodes a mitochondrial Ras protein. The three related males described had varying degrees of cognitive impairment, sensorineural hearing loss, short stature, dysmorphic facies, and other morphological defects. Conclusion: We herein present an unrelated 20-year-old male with similar manifestations also with p.D59G in the RAB40AL gene, which supports the existence of this condition previously coined as Martin-Probst syndrome (OMIM: 300519).