A neuromuscular disease characterized by congenital weakness, arthrogryposis, cleft palate, ptosis, myopathic facies, short stature, kykphoscoliosis, talipes deformities and susceptibility to malignant hyperthermia provoked by anesthesia and that has_material_basis_in homozygous mutation in the STAC3 gene on chromosome 12q13. [ http://purl.obolibrary.org/obo/ECO_0007645 ]