A MORC2 Variant Associated With Severe Intellectual Disability and Unusual Phenotype

The microrchidia CW-type zinc finger protein 2 (MORC2) gene encodes an epigenetic regulator, variants in which are often associated with Charcot-Tooth-Marie (CMT) disease type 2Z. In recent years, notable phenotypic variation has been identified in patients with different MORC2 variants. Here, we present a 61-year-old male with a MORC2 c.328C>T, p.(Arg110Cys) variant who displays significant but nonprogressive intellectual disability, hearing loss, retinitis pigmentosa, spasticity, and cerebellar findings, in addition to a mild neuropathy, with follow-up over 12 years. As the oldest reported patient with this variant and phenotype, this case not only expands the phenotypic spectrum of MORC2-related disorders but also provides valuable phenotypic information regarding disease progression in later years, particularly regarding the intellectual disabilities associated with MORC2 variants.