Mutational screening ruled out mutations in the SPG4 and SPG7 genes in Pt2, due to the presence of spastic tetraparaparesis; in the HTT gene in Pt1, due to the subtle onset of symptoms consistent with an affective disorder, together with cognitive dysfunction; and in the UBQLN2 and C9orf72 genes, recently associated to ALS/FTD, in both. The gene discussed is HTT; the disease is amyotrophic lateral sclerosis.