Spinal Muscular Atrophy, Lower Extremity-Predominant, 2b, Prenatal Onset, Autosomal Dominant, also known as spinal muscular atrophy, lower extremity-predominant, 2b, autosomal dominant, is related to spinal muscular atrophy with lower extremity predominant 2b. An important gene associated with Spinal Muscular Atrophy, Lower Extremity-Predominant, 2b, Prenatal Onset, Autosomal Dominant is BICD2 (BICD Cargo Adaptor 2). Affiliated tissues include brain and skeletal muscle, and related phenotypes are talipes equinovarus and multiple joint contractures