ASCC1 biallelic variants causes the Spinal muscular atrophy with congenital bone fractures 2 (SMABF2) [MIM: 616867], that is a very rare and severe autosomal recessive neuromuscular disorder characterized by congenital contractures, consistent with arthrogryposis multiplex congenita, and increased incidence of prenatal fractures of the long bones. Reduced fetal movements and polyhydramnios are the most recurrent features recorded during pregnancy. The prognosis is poor, because affected infants have difficulty of breathing and feeding and often die in the first months or years of life. When performed, skeletal muscle biopsy disclosed atrophic and immature muscle fibers, myofibrillar disorganization and enlarged Z-bands. The estimated incidence of SMABF2 related to ASCC1 alteration would be in the order of 2x107
ASCC1