has material basis in germline mutation in BICD2 autosomal dominant childhood-onset proximal spinal muscular atrophy with contractures https://github.com/monarch-initiative/mondo/issues/4521 https://www.malacards.org/card/spinal_muscular_atrophy_lower_extremity_predominant_2a_childhood_onset_autosomal_dominant https://www.malacards.org/card/spinal_muscular_atrophy_with_lower_extremity_predominant_2a Orphanet:363454 Lower extremity-predominant autosomal dominant proximal spinal muscular atrophy with contractures MONDO:0014121 GARD:0013222 spinal muscular atrophy, lower extremity-predominant 2, autosomal dominant OMIM:615290 autosomal dominant spinal muscular atrophy, lower extremity-predominant 2 spinal muscular atrophy, lower extremity-predominant, 2A, autosomal dominant DOID:0070349 SMALED2 UMLS:C4747715 MEDGEN:1669929 spinal muscular atrophy, LOWER extremity-predominant, 2, autosomal dominant autosomal dominant childhood-onset proximal spinal muscular atrophy