A homozygous deletion in the SLC19A1 gene as a cause of folate-dependent recurrent megaloblastic anemia
Abstract
Megaloblastic anemia resulting from ineffective hematopoiesis in the bone marrow (BM) is one of the main hematologic signs of folate or vitamin B12 deficiency. Functional deficiencies of these 2 vitamins originate from nutritional, gastrointestinal, or genetic factors, and their clinical symptoms result from the impaired synthesis of nucleotides in hematopoietic cells and S-adenosylmethionine in the nervous system.1 Folates are pteroyl(poly)glutamate derivatives with various 1-carbon moieties at the pterine ring, with the major circulating form being 5-methyltetrahydrofolate.
Folates are delivered to tissues by at least 5 transporters with different kinetic properties and variable expression.2,3 Two inherited disorders in folate transport, hereditary folate malabsorption and cerebral folate deficiency resulting from mutations in the SLC46A14 and FOLR15 genes, have been reported in humans.