Congenital myasthenic syndromes (CMSs) are a group of rare genetic disorders of the neuromuscular junction resulting in structural or functional causes of fatigable weakness that usually begins early in life. Mutations in pre-synaptic, synaptic and post-synaptic proteins have been demonstrated in human cases, with more than half involving aberrations in nicotinic acetylcholine receptor (AChR) subunits. CMS was first recognized in dogs in 1974 as an autosomal recessive trait in Jack Russell Terriers (JRTs). A deficiency of junctional AChRs was demonstrated. Here we characterize a CMS in 2 contemporary cases of JRT littermates with classic clinical and electromyographic findings, and immunochemical confirmation of an approximately 90% reduction in AChR protein content. Loci encoding the 5 AChR subunits were evaluated using microsatellite markers, and CHRNB1 and CHRNE were identified as candidate genes. Sequences of the splice sites and exons of both genes revealed a single base insertion in exon 7 of CHRNE that predicts a frameshift mutation and a premature stop codon. We further demonstrated this pathogenic mutation in CHRNE in archival tissues from unrelated JRTs studied 34 years ago.
        
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Rinz CJ, Lennon VA, James F, Thoreson JB, Tsai KL, Starr-Moss AN, Humphries HD, Guo LT, Palmer AC, Clark LA, Shelton GD (2015) A CHRNE frameshift mutation causes congenital myasthenic syndrome in young Jack Russell Terriers Neuromuscular Disorders25: 921-7
Rinz CJ, Lennon VA, James F, Thoreson JB, Tsai KL, Starr-Moss AN, Humphries HD, Guo LT, Palmer AC, Clark LA, Shelton GD (2015) Neuromuscular Disorders25: 921-7