has characteristic has characteristic has material basis in germline mutation in UBA1 Infantile onset spinal muscular atrophy congenital nervous system disorder infantile-onset X-linked spinal muscular atrophy https://github.com/monarch-initiative/mondo/issues/4521 https://www.malacards.org/card/spinal_muscular_atrophy_x_linked_2 GARD:0008521 spinal muscular atrophy, X-linked 2, infantile, X-linked recessive spinal muscular atrophy, X-linked type 2 DOID:0111827 UMLS:C1844934 MESH:C535380 spinal muscular atrophy, X-linked 2 X-linked spinal muscular atrophy type 2 MONDO:0010532 spinal muscular atrophy with arthrogryposis MEDGEN:337123 A rare form of spinal muscular atrophy characterized by the neonatal onset of severe hypotonia, areflexia, profound weakness, multiple congenital contractures, facial dysmorphic features (myopathic face with open, tent-shaped mouth), cryptorchidism, and mild skeletal abnormalities (i.e. kyphosis, scoliosis), that is often preceded by polyhydramnios and reduced fetal movements in utero and followed by bone fractures shortly after birth. SMAX2 patients often have a limited life span, often succumbing to the disease within 2 years, as muscle weakness is progressive and chest muscle involvement eventually leads to ventilatory insufficiency and respiratory failure. SCTID:719836007 X-linked distal arthrogryposis multiplex congenita OMIM:301830 SMAX2 Orphanet:1145 arthrogryposis multiplex congenita