Abnormalities in fat accumulation and fatty acid metabolism have previously been identified in patients with MND affecting both upper (UMNs) and lower motor neurons (LMNs), such as amyotrophic lateral sclerosis (ALS) [2], as well as spinal muscular atrophy (SMA) from deletion in the SMN1 gene, which selectively targets LMNs [3]. Here, SMN1 is linked to proximal spinal muscular atrophy.