They would be ALS2-related disorders of the UMN spectrum, most probably of IAHSP type although considering the marked affectation differences of F1 siblings, and it is tempting to speculate that same genotype (Q982SfsX19/R704X) might be associated to different disorders, being that of index case a typical example of IAHSP whereas that of his old sister would also be compatible with diagnosis of an early-onset JPLS. This evidence concerns the gene ALS2 and juvenile primary lateral sclerosis.