ALS deficiency caused by an exon 2 deletion and a novel missense variant in the gene encoding ALS.

•Description of ACLSD novel genetic cause in the first reported Chilean patient.•The first larger deletion involving exon 2 of IGFALS, demonstrated by MLPA.•On the other allele we find a missense variant not described in a clinical context.•In available relatives, some had one of the variants and reduced ALS concentration.