Identification of a 4-base deletion in the gene in inherited intrinsic factor deficiency.
A 4-base deletion has been identified in the coding region of the gene for gastric intrinsic factor (IF) in an 11-year-old girl with severe anemia and cobalamin (Cbl) deficiency. The bone marrow showed frank megaloblastic morphology, and the Schilling test indicated a failure to absorb Cbl that was corrected by coadministration of IF. Pentagastrin administration induced acid secretion, but the gastric juice lacked IF as determined by CbI binding, by fractionation of protein-bound CbI, and by immunoprecipitation with anti-IF antiserum. Individual exons were amplified by the polymerase chain reaction by using primers to the flanking intronic regions, and the nucleotide sequence analysis identified a 4-base deletion (c183_186delGAAT) spanning positions 104 to 107 in exon 2, resulting in premature termination of translation. This mutation also eliminates a site for Bst XI endonuclease and introduces a site for BsaBI for identifying this deletion in hereditary IF deficiency.
Yassin
Fawwaz
F
Department of Medicine and Biochemistry, State University of New York Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 11203, USA.
Rothenberg
Sheldon P
SP
Rao
Sreedhar
S
Gordon
Marilyn M
MM
Alpers
David H
DH
Quadros
Edward V
EV
D000749:Anemia, Megaloblastic / Q000175:diagnosis / Q000235:genetics*; D002648:Child; D005260:Female; D005750:Gastric Juice; D017353:Gene Deletion; D006801:Humans; D007437:Intrinsic Factor / Q000172:deficiency / Q000235:genetics*; D010418:Pentagastrin; D014805:Vitamin B 12 / Q000493:pharmacokinetics; D014806:Vitamin B 12 Deficiency / Q000175:diagnosis / Q000235:genetics*
D007437:Intrinsic Factor; D010418:Pentagastrin; D014805:Vitamin B 12