The genetic and clinical features of MORC2 gene-related neuropathy in Chinese patients / 中华神经科杂志

ABSTRACT

Objective:To summarize the genetic and phenotypic features of MORC family CW-type zinc finger 2 (MORC2) gene-related neuropathy in Chinese patients. Methods:The clinical and whole exome sequencing data of MORC2 gene-related neuropathy families with a definitive genetic diagnosis were collected from the Third Xiangya Hospital of Central South University between 2010 and 2023. Literature involving Chinese families with MORC2 gene-related neuropathy was extensively reviewed to provide a comprehensive summary of the genetic and phenotypic spectrum of the disease. Results:A total of 10 families with MORC2 gene-related neuropathy were identified and analyzed. Six different heterozygous pathogenic variants in the MORC2 gene were observed among these families, including the novel variant c.1330G>C (p.G444R) that had not been previously reported. Six families presented as axonal Charcot-Marie-Tooth disease caused by variants in the MORC2 gene (CMT2Z) phenotype with childhood or adult onset, and carried variants c.754C>T (p.R252W), c.1199A>G (p.Q400R), c.1330G>C (p.G444R), or c.1396G>A (p. D466N); 3 families manifested as severe spinal muscular atrophy (SMA)-like phenotype with infantile onset, all carried c.260C>T (p.S87L); 1 family carried c.1181A>G (p.Y394C), presented as DIGFAN syndrome phenotype with infantile onset combined with mental and motor retardation. Systematic review showed 8 Chinese families carried pathogenic variants of the MORC2 gene, among which 5 families were associated with the CMT2Z phenotype, carrying c.754C>T (p.R252W), c.1079A>G (p.E360G), c.1220G>A (p.C407Y), or c.1397A>G (p.D466G); 1 family was associated with SMA-like phenotype, carrying c.260C>T (p.S87L); and 2 families were associated with DIGFAN syndrome, carrying c.79G>A (p.E27K) and c.292G>A (p.G98R). Conclusions:A novel pathogenic variant c.1330G>C (p.G444R) of the MORC2 gene associated with the CMT2 phenotype is reported. Eleven pathogenic variants of the MORC2 gene have been reported in the Chinese patients to date, and c.754C>T(p.R252W) may be the most common. Patients with MORC2 gene-related neuropathy carrying different variants present with significant clinical heterogeneity, manifesting as CMT2Z, early-onset severe SMA-like myasthenia, or DIGFAN syndrome.