MUTATIONS IN VAPB ARE NOT ASSOCIATED WITH SPORADIC ALS

ALS is the third most common adult-onset neurodegenerative disorder. The majority of cases are sporadic (SALS), whereas 5 to 10% are familial (FALS). There are 13 known loci, with causative genes identified at seven, including superoxide dismutase 1 (SOD1) and angiogenin (ANG).1,2 Recently, mutations in vesicle-associated membrane protein (VAMP) associated protein B (VAPB) have been associated with autosomal dominant, adult-onset ALS8.3

VAPB is ubiquitously expressed, and evidence suggests that it plays a role in vesicle trafficking.4 As VAPB was the only gene, other than SOD1, known to cause adult-onset, autosomal dominant ALS, we undertook a mutation screening strategy to establish the contribution of VAPB mutations in a large cohort of ALS patients. Although it is appreciated that mutations would be most likely to be found in familial cases, mutations in SOD1 and more recently ANG have been reported in SALS. Therefore, both FALS and SALS cases were screened for mutations in VAPB.