Cobalamin C defect: natural history, pathophysiology, and treatment.
Summary of "Cobalamin C defect: natural history, pathophysiology, and treatment."
Cobalamin C (Cbl-C) defect is the most common inborn cobalamin metabolism error; it causes impaired conversion of dietary vitamin B12 into its two metabolically active forms, methylcobalamin and adenosylcobalamin. Cbl-C defect causes the accumulation of methylmalonic acid and homocysteine and decreased methionine synthesis. The gene responsible for the Cbl-C defect has been recently identified, and more than 40 mutations have been reported. MMACHC gene is located on chromosome 1p and catalyzes the reductive decyanation of CNCbl. Cbl-C patients present with a heterogeneous clinical picture and, based on their age at onset, can be categorized into two distinct clinical forms. Early-onset patients, presenting symptoms within the first year, show a multisystem disease with severe neurological, ocular, haematological, renal, gastrointestinal, cardiac, and pulmonary manifestations. Late-onset patients present a milder clinical phenotype with acute or slowly progressive neurological symptoms and behavioral disturbances. To improve clinical course and metabolic abnormalities, treatment of Cbl-C defect usually consists of a combined approach that utilizes vitamin B12 to increase intracellular cobalamin and to maximize deficient enzyme activities, betaine to provide a substrate for the conversion of homocysteine into methionine through betaine-homocysteine methyltransferase, and folic acid to enhance remethylation pathway. No proven efficacy has been demonstrated for carnitine and dietary protein restriction. Despite these measures, the long-term follow-up is unsatisfactory especially in patients with early onset, with frequent progression of neurological and ocular impairment. The unfavorable outcome suggests that better understanding of the pathophysiology of the disease is needed to improve treatment protocols and to develop new therapeutic approaches.
Affiliation
Division of Metabolism, Bambino Gesù Children's Hospital, Piazza S. Onofrio 4, 00165, Rome, Italy.
Journal Details
This article was published in the following journal.
Name: Journal of inherited metabolic disease
ISSN: 1573-2665
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20632110
- DOI: http://dx.doi.org/10.1007/s10545-010-9161-z
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A former branch of knowledge embracing the study, description, and classification of natural objects (as animals, plants, and minerals) and thus including the modern sciences of zoology, botany, and mineralogy insofar as they existed at that time. In the 17th, 18th, and 19th centuries it was much used for the generalized pursuit of certain areas of science. (Webster, 3d ed; from Dr. James H. Cassedy, NLM History of Medicine Division)
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Pentalogy Of Cantrell
Rare congenital deformity syndrome characterized by a combination of five anomalies as a result of neural tube defect. The five anomalies are a midline supraumbilical abdominal wall defect (e.g., OMPHALOCELE), a lower STERNUM defect, a congenital intracardiac defect, an anterior DIAPHRAGM defect, and a diaphragmatic PERICARDIUM defect (e.g., PERICARDIAL EFFUSION). Variants with incomplete and variable combinations of the defects are known. ECTOPIA CORDIS; CLEFT LIP; and CLEFT PALATE are often associated with the syndrome.
Philology
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History, Medieval
The period of history from the year 500 through 1450 of the common era.
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