Whitehead V Michael
The Hematology Service, Montreal Children's Hospital and the McGill University-Montreal Children's Hospital Research Institute of the McGill University Health Center, Montreal, QC, Canada.
Br J Haematol. 2006 Jul;134(2):125-36. doi: 10.1111/j.1365-2141.2006.06133.x.
Cobalamin deficiency in the newborn usually results from cobalamin deficiency in the mother. Megaloblastic anaemia, pancytopenia and failure to thrive can be present, accompanied by neurological deficits if the diagnosis is delayed. Most cases of spina bifida and other neural tube defects result from maternal folate and/or cobalamin insufficiency in the periconceptual period. Polymorphisms in a number of genes involved in folate and cobalamin metabolism exacerbate the risk. Inborn errors of cobalamin metabolism affect its absorption, (intrinsic factor deficiency, Imerslund-Gräsbeck syndrome) and transport (transcobalamin deficiency) as well as its intracellular metabolism affecting adenosylcobalamin synthesis (cblA and cblB), methionine synthase function (cblE and cblG) or both (cblC, cblD and cblF). Inborn errors of folate metabolism include congenital folate malabsorption, severe methylenetetrahydrofolate reductase deficiency and formiminotransferase deficiency. The identification of disease-causing mutations in specific genes has improved our ability to diagnose many of these conditions, both before and after birth.
新生儿钴胺素缺乏通常源于母亲的钴胺素缺乏。可能会出现巨幼细胞贫血、全血细胞减少和发育不良，如果诊断延迟还会伴有神经功能缺损。大多数脊柱裂和其他神经管缺陷病例是由于母亲在受孕前后叶酸和/或钴胺素不足所致。一些参与叶酸和钴胺素代谢的基因多态性会增加风险。钴胺素代谢的先天性缺陷会影响其吸收（内因子缺乏、Imerslund-Gräsbeck综合征）和转运（转钴胺素缺乏），以及影响腺苷钴胺素合成（cblA和cblB）、甲硫氨酸合酶功能（cblE和cblG）或两者（cblC、cblD和cblF）的细胞内代谢。叶酸代谢的先天性缺陷包括先天性叶酸吸收不良、严重的亚甲基四氢叶酸还原酶缺乏和亚胺甲基转移酶缺乏。特定基因中致病突变的鉴定提高了我们在出生前后诊断许多此类疾病的能力。
