Genetic Spectrum and Variability in Chinese Patients with Amyotrophic Lateral Sclerosis

Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease characterized by selective impairment of upper and lower motor neurons. We aimed to investigate the genetic spectrum and variability in Chinese patients with ALS. A total of 24 familial ALS (FALS) and 21 early-onset sporadic ALS (SALS) of Chinese ancestry were enrolled. Targeted next-generation sequencing (NGS) was performed in the probands, followed by verification by Sanger sequencing and co-segregation analysis. Clinical features of patients with pathogenic or likely pathogenic variants were present. The mutation frequency of ALS-related genes was then analyzed in Chinese population. In this cohort, 17 known mutations (9 SOD1, 5 FUS, 2 TARDBP and one SETX) were identified in 14 FALS and 6 early-onset SALS. Moreover, 7 novel variants (SOD1 c.112G>C, OPTN c.811C>T, ERBB4 c.965T>A, DCTN1 c.1915C>T, NEFH c.2602G>A, NEK1 c.3622G>A, and TAF15 c.1535G>A) were identified. In southeastern Chinese FALS, the mutation frequency of SOD1, FUS, and TARDBP was 52.9%, 8.8%, 8.8% respectively. In early-onset SALS, FUS mutations were the most common (22.6%). In Chinese ALS cases, p.H47R is most frequent SOD1 mutations, while p.R521 is most common FUS mutation and p.M337V is most common TARDBP mutation. Our results revealed that mutations in SOD1, FUS and TARDBP are the most common cause of Chinese FALS, while FUS mutations are the most common cause of early-onset SALS. The genetic spectrum is different between Chinese ALS and Caucasian ALS.

Keywords: Chinese ancestry; amyotrophic lateral sclerosis; genetic spectrum; mutation; targeted next-generation sequencing.

Figure 1.

Mutation spectrum of ALS-linked genes in our ALS cohort and Chinese ALS patients. (A) In our ALS cohort, the mutation frequency of SOD1, FUS, TARDBP, and DCTN1 in FALS was 52.9%, 8.8%, 8.8%, and 2.9%, respectively. FUS mutations were the most common cause of early-onset SALS (25.8%), while 61.3% of the cases were not identified pathogenic mutations. (B) The mutation frequency of FUS in Chinese ALS cases. (C) The mutation frequency of TARDBP in Chinese ALS cases. (D) The mutation frequency of SOD1 in Chinese ALS cases.