ERBB4 and amyotrophic lateral sclerosis: In three of the 25 genes, structural variation was associated with ALS: C9orf72 gene hexanucleotide repeat expansion (odds ratio 28.1, 95% CI (10.45, 75.61), p = 2 × 10−16), inversion in the VCP gene (odds ratio 2.33, 95% CI (2.09, 2.61), p = 2 × 10−5) and insertion in the ERBB4 gene (odds ratio 2.55, 95% CI (2.26, 2.88), p = 3 × 10−5; (Table 2, Supplementary appendix Table 2–6).