The genetic distribution in Chinese patients with Charcot-Marie-Tooth diseases: a 14-year cohort study / 中华神经科杂志

ABSTRACT

Objective:To investigate the genetic distribution of pathogenic genes of Charcot-Marie-Tooth diseases (CMT) in Chinese Han population, and compare the similarity and difference with the data in Peking University Third Hospital in 2013.Methods:Five hundred and twenty families with CMT and related diseases in Peking University Third Hospital and China-Japan Friendship Hospital from January 2007 to March 2021 were collected. After peripheral myelin protein 22 (PMP22) gene duplication and deletion mutations were initially detected by multiple ligation probe amplification, the probands of these families were sequenced by next-generation sequencing (NGS) gene panel or whole exome sequencing, and validated by Sanger sequencing.Results:Among the 520 families, 336 CMT families were genetically confirmed, and the mutation detection rate increased from 48.6% (51/105) in 2013 to 64.6% (336/520) in 2021 (χ 2=9.54, P=0.003). Among them, 139 families had PMP22 gene duplication mutation (139/520, 26.7%), 46 families had gap junction beta-1 (GJB1) gene mutation (46/520, 8.8%), 26 families had mitofusin-2 (MFN2) gene mutation (26/520, 5.0%), 12 families had myelin protein zero (MPZ) gene mutation (12/520, 2.3%), 11 families had PMP22 gene point mutation (11/520, 2.1%), and 10 families had heat shock protein B1 gene mutation (10/520, 1.9%). There were 10 families with ganglioside induced differentiation associated protein 1 (GDAP1) gene mutation (10/520, 1.9%), 8 families with SH3 domain and tetratricopeptide repeats 2 (SH3TC2) gene mutation (8/520, 1.5%), 7 families with immunoglobulin mu DNA binding protein 2 (IGHMBP2) gene mutation (7/520, 1.3%), 6 families with MORC family CW-type zinc finger 2 (MORC2) gene mutation (6/520, 1.2%), 5 families with sorbitol dehydrogenase (SORD) gene mutation (5/520, 1.0%), 16 families with very rare gene mutation (16/520, 3.1%) and 184 families without genetic diagnosis (184/520, 35.4%). Conclusions:Compared with the results in 2013, the 3 most common genes affecting CMT were still PMP22, GJB1 and MFN2 genes, but the proportion difference of patients with MPZ gene mutation gradually decreased with other genes such as SH3TC2 and GDAP1 genes. The proportion of newly discovered CMT genes, such as MORC2 and SORD genes, was similar with IGHMBP2 gene, which should be paid more attention. NGS greatly improved the detection rate of CMT, especially for patients with autosomal recessive-CMT.