cobamamide and Vitamin-B-Deficiency

Topics: 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; Animals; Bacterial Proteins; Biological Evolution; Biological Transport; Cells, Cultured; Child; Cobamides; Female; Fibroblasts; Genes; Genetic Complementation Test; Homocystinuria; Humans; Incidence; Infant, Newborn; Intestinal Absorption; Intrinsic Factor; Male; Metabolism, Inborn Errors; Methylmalonic Acid; Methylmalonyl-CoA Mutase; Mice; Transcobalamins; Vitamin B 12; Vitamin B Deficiency

Hyperpigmentation of the hands and feet developed in a 65-year-old Korean woman who had undergone a total gastrectomy and esophagojejunostomy due to early gastric cancer 7 years previously. A diagnosis of megaloblastic anemia due to vitamin B12 deficiency was made. In the areas of pigmentation, there were abnormally large nuclei in the keratinocytes. All of these findings were reversible upon the administration of vitamin B12. Ultrastructurally, there were many intracytoplasmic desmosomes, numerous aggregated bundles of tonofilaments, and highly condensed keratohyalin granules. The pathophysiologic mechanism of vitamin B12 deficiency associated with pigmentary disturbances and change of nuclear size is discussed.

Topics: Anemia, Macrocytic; Anemia, Megaloblastic; Biopsy; Cobamides; Female; Gastrectomy; Hand Dermatoses; Humans; Middle Aged; Pigmentation Disorders; Skin; Vitamin B Deficiency