While Amyotrophic Lateral Sclerosis (ALS) represents the most common form, other MNDs, including Primary Lateral Sclerosis (PLS), Hereditary Spastic Paraplegia (HSP), Spinal Muscular Atrophy with Respiratory Distress Type 1 (SMARD1), Multisystem Proteinopathy (MSP), Spinal and Bulbar Muscular Atrophy (SBMA), and ALS associated to Frontotemporal Dementia (ALS-FTD), contribute significantly to the clinical and biological complexity of these diseases spectrum [1,2]. The gene discussed is IGHMBP2; the disease is proximal spinal muscular atrophy.