title: X-linked spinal muscular atrophy (SMAX2) caused by de novo c.1731C>T substitution in the UBA1 gene.
abstract: Infantile X-linked spinal muscular atrophy (SMAX2) is a rare form of spinal muscular atrophy manifesting as severe hypotonia, areflexia, arthrogryposis, facial weakness and cryptorchidism, and frequently accompanied by bone fractures. We present a male patient with SMAX2 who presented with typical symptoms at birth, preceded by reduced fetal movements in the second and third trimesters of pregnancy. Clinical examination revealed a myopathic face with a characteristic tent-shaped open mouth, tongue fibrillations, profound muscle weakness, areflexia, multiple contractures, mild skeletal abnormalities and cryptorchidism. In the first days of the patient's life, fractures of the right femur and right humerus were found; however, calcium-phosphate metabolism and densitometric examination were normal. Molecular analysis revealed a de novo c.1731C>T substitution in the UBA1 gene, which was localized in exon 15, the specific hot spot for mutation.
authors.affiliation: Neuromuscular Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland. Electronic address: mjedrzejowska@imdik.pan.pl.
authors.forename: Maria
authors.initials: M
authors.lastname: Jędrzejowska
authors.affiliation: Department of Pediatric Propedeutics and Bone Metabolism Diseases, Medical University of Lodz, Poland.
authors.forename: Elżbieta
authors.initials: E
authors.lastname: Jakubowska-Pietkiewicz
authors.affiliation: Department of Neurology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kostera-Pruszczyk
mesh_terms: D001176:Arthrogryposis / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D050723:Fractures, Bone / Q000151:congenital; D040181:Genetic Diseases, X-Linked / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D009154:Mutation; D044764:Ubiquitin-Activating Enzymes / Q000235:genetics*
chemical_list: C471538:UBA1 protein, human; D044764:Ubiquitin-Activating Enzymes
keywords: Arflexia; Arthrogryposis; Congenital fractures; Hypotonia; SMAX2; UBA1 gene