Molecular analyses
A heterozygous mutation, c.714 716delGAA, p.Lys238del, was identified in the exon 5 of SQSTM1 gene in the three affected siblings (007, 008, 009). The mutation was validated by the Sanger method in the three patients (Fig. 1). The Lys238 residue is conserved across species. The mutation was previously identified as a disease-causing mutation in ALS patients [4] and was predicted to be deleterious by SIFT/PROVEAN in silico software (score: −11.7). Furthermore, this mutation was absent from 350 French controls, from 6,503 individuals of the ‘exome variant server’ (http://evs.gs.washington.edu/EVS/), dbSNP (http://www.ncbi.nlm.nih.gov/projects/SNP/) and 1000Genomes (http://www.1000genomes.org/) databases, thus strongly supporting its deleterious effect.