Loss-of-function mutations in Lysyl-tRNA synthetase cause various leukoencephalopathy phenotypes

Chong Sun, Jie Song, Yanjun Jiang, Chongbo Zhao, Jiahong Lu, Yuxin Li, Yin Wang, Mingshi Gao, Jianying Xi, Sushan Luo, Meixia Li, Kevin Donaldson, Stephanie N. Oprescu, Thomas P. Slavin, Sansan Lee, Pilar L. Magoulas, Andrea M. Lewis, Lisa Emrick, Seema R. Lalani, Zhiyv NiuMegan L. Landsverk, Magdalena Walkiewicz, Richard E. Person, Hui Mei, Jill A. Rosenfeld, Yaping Yang, Anthony Antonellis, Ya Ming Hou, Jie Lin, Victor W. Zhang

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Objective: To expand the clinical spectrum of lysyl-tRNA synthetase (KARS) gene-related diseases, which so far includes Charcot-Marie-Tooth disease, congenital visual impairment and microcephaly, and nonsyndromic hearing impairment. Methods: Whole-exome sequencing was performed on index patients from 4 unrelated families with leukoencephalopathy. Candidate pathogenic variants and their cosegregation were confirmed by Sanger sequencing. Effects of mutations on KARS protein function were examined by aminoacylation assays and yeast complementation assays. Results: Common clinical features of the patients in this study included impaired cognitive ability, seizure, hypotonia, ataxia, and abnormal brain imaging, suggesting that the CNS involvement is the main clinical presentation. Six previously unreported and 1 known KARS mutations were identified and cosegregated in these families. Two patients are compound heterozygous for missense mutations, 1 patient is homozygous for a missense mutation, and 1 patient harbored an insertion mutation and a missense mutation. Functional and structural analyses revealed that these mutations impair aminoacylation activity of lysyl-tRNA synthetase, indicating that defective KARS function is responsible for the phenotypes in these individuals. Conclusions: Our results demonstrate that patients with loss-of-function KARS mutations can manifest CNS disorders, thus broadening the phenotypic spectrum associated with KARS-related disease.

Original languageEnglish (US)
Article numbere316
JournalNeurology: Genetics
Volume5
Issue number2
DOIs
StatePublished - Apr 1 2019

ASJC Scopus subject areas

  • Clinical Neurology
  • Genetics(clinical)

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    Sun, C., Song, J., Jiang, Y., Zhao, C., Lu, J., Li, Y., Wang, Y., Gao, M., Xi, J., Luo, S., Li, M., Donaldson, K., Oprescu, S. N., Slavin, T. P., Lee, S., Magoulas, P. L., Lewis, A. M., Emrick, L., Lalani, S. R., ... Zhang, V. W. (2019). Loss-of-function mutations in Lysyl-tRNA synthetase cause various leukoencephalopathy phenotypes. Neurology: Genetics, 5(2), [e316]. https://doi.org/10.1212/NXG.0000000000000316