Amyotrophic lateral sclerosis (ALS) can present with heterogeneous symptoms resulting from the involvement of multiple brain systems including extramotor cortical areas. Involvement of other brain areas can cause diverse clinical symptoms including cognitive impairment and extrapyramidal symptoms. We report the case of a 50-year-old woman with bulbar onset ALS and frontotemporal lobar degeneration (FTLD), confirmed as cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). The patient and her first-degree relatives harbored a mutation (R75P) in the NOTCH3 gene, indicative of vascular deficits. The details of this case add plausibility to the idea that ALS, FTLD, and CADASIL are different aspects of a spectrum of disorders with overlapping pathologic mechanisms.