Mutations in the cytoplasmic dynein 1 heavy chain 1 gene (DYNC1H1) were first described in 2010 in autosomal dominant lower extremity-predominant spinal muscular atrophy 1 (SMALED1; MIM#158600) [1, 2]. This evidence concerns the gene DYNC1H1 and autosomal dominant childhood-onset proximal spinal muscular atrophy.