Truncating mutations in the Wilson disease gene ATP7B are associated with very low serum ceruloplasmin oxidase activity and an early onset of Wilson disease
نویسندگان
چکیده
BACKGROUND Mutations in the gene ATP7B cause Wilson disease, a copper storage disorder with a high phenotypic and genetic heterogeneity. We aimed to evaluate whether 'severe' protein-truncating ATP7B mutations (SMs) are associated with low serum ceruloplasmin oxidase activities and an early age of onset when compared to missense mutations (MMs). METHODS The clinical phenotype of 59 genetically confirmed WD patients was analyzed retrospectively. Serum ceruloplasmin was measured by its oxidase activity with o-dianisidine dihydrochloride as substrate and immunologically. RESULTS Thirty-nine patients had two MMs, 15 had the genotype SM/MM, and 5 patients had two SMs on their ATP7B alleles. Enzymatic and immunologic serum ceruloplasmin levels differed significantly between the three groups (P < 0.001 and P < 0.01, respectively). The lowest levels were measured in patients with two SMs (0.0 U/L; IQR, 0.0-0.0 U/L and 0.02 g/L; IQR, 0.01-0.02 g/L, respectively) and the highest in patients with two MMs (17.8 U/L; IQR, 5.8-35.1 U/L and 0.11 g/L; IQR,0.10-0.17 g/L, respectively). The age of onset was also significantly different between the three patient groups (P < 0.05), with SM/SM patients showing the earliest onset (13 years; IQR, 9-13 years) and patients with two MMs showing the latest onset (22 years; IQR, 14-27 years). By ROC curve analysis a ceruloplasmin oxidase level <or= 5 U/L can predict the presence of at least one SM with a sensitivity of 80% and a specificity of 79.5%. CONCLUSIONS In our German study cohort truncating ATP7B mutations were associated with lower ceruloplasmin serum oxidase levels and an earlier age of onset when compared to MMs. Measurement of serum ceruloplasmin oxidase might help to predict presence of truncating ATP7B mutations and might facilitate the mutation analysis.
منابع مشابه
Molecular Genetics Diagnosis of Wilson Disease: the First Reported Case of ATP7BGene Mutation at Codon 778 in Southwest Iran
Wilson disease is a metabolic disorder with an autosomal recessive genetic pattern and occurs in 1-4 of every 100000 individuals. Inactivation of the ATP7B gene leads to accumulation of the toxic copper to liver and brain causing hepatic and neurological complication. Therefore, most patients suffer from chronic hepatic inflammation and central nervous system disorder. Nowadays, up to ...
متن کاملNovel mutations in ATP7B gene of Wilson\'s disease in Iranian patients
Bacground: Wilson's disease is a rare autosomal recessive disorder characterized by toxic accumulation of copper in liver and brain. The disorder is caused by mutations in the ATP7B gene, encoding a copper transporting P-type ATPase. Characterization of the spectrum of mutations in this gene is important both for diagnosis and genetic counseling of the families. Materials and Methods: We enrol...
متن کاملSpectrum of ATP7B Gene Mutations in Pakistani Wilson Disease Patients: A Novel Mutation Is Associated with Severe Hepatic and Neurological Complication
Wilson disease (WND) is an autosomal recessive disorder caused by mutation in ATP7B gene that impairs copper metabolism. ATP7B is involved in the transport of copper into the plasma protein ceruloplasmin and copper excretion out of the liver. Defects in ATP7B lead to excess of copper in various organs primarily in liver. The diagnosis of WND is more complex due to variations in its biochemical ...
متن کاملThe copper-transporting ATPases, menkes and wilson disease proteins, have distinct roles in adult and developing cerebellum.
Copper is essential for brain metabolism, serving as a cofactor to superoxide dismutase, dopamine-beta-hydroxylase, amyloid precursor protein, ceruloplasmin, and other proteins required for normal brain function. The copper-transporting ATPases ATP7A and ATP7B play a central role in distribution of copper in the central nervous system; genetic mutations in ATP7A and ATP7B lead to severe neurode...
متن کاملHypoparathyroidism as a rare manifestation of Wilson,s disease: a case report
A 13 years old girl was admitted to the pediatric ward of hospital No 1 of Kerman university of medical sciences because of crampy pains, pins and needles sensation of the extremities and history of an episode of seizure. Her problem started one week prior to admission with pain in the leg muscles, flexion of the fingers followed by seizure. On physical examination, the prominent finding inclu...
متن کامل