has material basis in autosomal recessive disease dystonia 31 A dystonia characterized by age at onset ranges from childhood to young adulthood with involuntary muscle twisting movements and postural abnormalities affecting the upper and lower limbs, neck, face, and trunk. Some patients may have orofacial dyskinesia resulting in articulation and swallowing difficulties that has_material_basis_in homozygous or compound heterozygous mutation in the AOPEP gene on chromosome 9q22. MIM:619565 DOID:0060938 disease_ontology DYT31 ZECH-BOESCH SYNDROME dystonia autosomal recessive inheritance