Impaired Function is a Common Feature of Neuropathy‐Associated Glycyl‐t RNA Synthetase Mutations

LB Griffin, R Sakaguchi, D McGuigan… - Human …, 2014 - Wiley Online Library
LB Griffin, R Sakaguchi, D McGuigan, MA Gonzalez, C Searby, S Züchner, YM Hou…
Human mutation, 2014Wiley Online Library
ABSTRACT C harcot–M arie–T ooth disease type 2 D (CMT 2 D) is an autosomal‐dominant
axonal peripheral neuropathy characterized by impaired motor and sensory function in the
distal extremities. Mutations in the glycyl‐t RNA synthetase (GARS) gene cause CMT 2 D.
GARS is a member of the ubiquitously expressed aminoacyl‐tRNA synthetase (ARS) family
and is responsible for charging t RNA with glycine. To date, 13 GARS mutations have been
identified in patients with CMT disease. While functional studies have revealed loss‐of …
Abstract
Charcot–Marie–Tooth disease type 2D (CMT2D) is an autosomal‐dominant axonal peripheral neuropathy characterized by impaired motor and sensory function in the distal extremities. Mutations in the glycyl‐tRNA synthetase (GARS) gene cause CMT2D. GARS is a member of the ubiquitously expressed aminoacyl‐tRNA synthetase (ARS) family and is responsible for charging tRNA with glycine. To date, 13 GARS mutations have been identified in patients with CMT disease. While functional studies have revealed loss‐of‐function characteristics, only four GARS mutations have been rigorously studied. Here, we report the functional evaluation of nine CMT‐associated GARS mutations in tRNA charging, yeast complementation, and subcellular localization assays. Our results demonstrate that impaired function is a common characteristic of CMT‐associated GARS mutations. Additionally, one mutation previously associated with CMT disease (p.Ser581Leu) does not demonstrate impaired function, was identified in the general population, and failed to segregate with disease in two newly identified families with CMT disease. Thus, we propose that this variant is not a disease‐causing mutation. Together, our data indicate that impaired function is a key component of GARS‐mediated CMT disease and emphasize the need for careful genetic and functional evaluation before implicating a variant in disease onset.
Wiley Online Library