Non-5q Spinal Muscular Atrophy in a Patient With a Novel BICD2 Missense Variant

Variants in BICD cargo adapter 2 (BICD2) cause autosomal dominant spinal muscular atrophy with lower extremity dominance (SMALED2) which is characterized muscle weakness and atrophy. We describe a novel, heterozygous BICD2 variant (c.1661T>C, [p.Leu554Pro]) 21-month-old female patient more severe phenotypic presentation than the typical SMALED2 expression including arthrogryposis multiplex congenita, absent deep tendon reflexes, respiratory insufficiency, cerebral depression. The p.Leu554Pro located just outside of domain that interacts motor protein KIF5A. detailed neuro-phenotyping clinical course presented here expand understanding related disease.