The rationale for this article is a description of a unique, familial case of a patient with amyotrophic lateral sclerosis (ALS), a progressive neurodegenerative disorder of unknown etiology coexisting with Klippel-Feil syndrome (KFS), a congenital malformation of cervical vertebrae, characterized by a fusion of minimum 2 cervical vertebrae. We report a 68-year-old man with moderate dysarthria, fasciculations, short neck, hearing deficit, and low posterior hairline. Definite ALS was diagnosed based on neurological abnormalities and electromyography results. Magnetic resonance imaging and computed tomography showed bony abnormalities of the craniocervical junction, fusion of 2 cervical vertebrae, and syringomyelia at the level of C6-C7. KFS phenotype was noted in 2 more family members, and patient's stepsister with KFS phenotype died due to ALS. The pedigree of our family suggests an autosomal-dominant inheritance of both syndromes. Cosegregation of ALS and KFS with an autosomal-dominant trait suggests an impairment of transforming growth factor β signaling pathway, and its potential role is discussed. Further evaluation of patients with autosomal-dominant and sporadic KFS by genetic testing, biochemical measurements, such as plasma transforming growth factor β1, and systematic follow-up electromyography seems warranted.