Synaptic Deficits at Neuromuscular Junctions in Two Mouse Models of Charcot–Marie–Tooth Type 2d

Patients with Charcot–Marie–Tooth Type 2D (CMT2D), caused by dominant mutations in Glycl tRNA synthetase (GARS), present with progressive weakness, consistently in the hands, but often in the feet also. Electromyography shows denervation, and patients often reportthat early symptoms include cramps brought on by cold or exertion. Based on reported clinical observations, and studies of mouse models of CMT2D, we soughtto determine whether weakened synaptictransmission atthe neuromuscular junction (NMJ) is an aspect of CMT2D. Quantal analysis of NMJs in two different mouse models of CMT2D (GarsP278KY, GarsC201R), found synaptic deficits that correlated with disease severity and progressed with age.