C9orf72 and amyotrophic lateral sclerosis: Zebrafish ALS models have been generated via the exposure of zebrafish larvae to cyanotoxins [269], through random mutagenesis via N-ethyl-N-nitrosourea to generate a SOD1 mutant model [38], or through genetic manipulation techniques involving transient gene overexpression via the mRNA microinjection of an incomplete C9orf72 construct [270], overexpression of SOD1 [271], morpholino knockdown of C9orf72 [270] or progranulin [272], and CRISPR-Cas9 [273,274].