The full human gene was isolated from PAC dJ100A14 and mutaginized (A>G) to introduce a p.H46R (substitution of histidine 46 with arginine) mutation in the encoded peptide. The transgene construct was micro-injected into (C57BL/6 x DBA/2)F1 embryos. The mutation represents a novel mutation found in some human familial amyotrophic lateral sclerosis (FALS) patients. Mouse line 70 expressed the human protein at 20-fold the level of the endogenous protein. The activity level of the mutated human protein was 20% of control level. (J:274745)