Homologous G776G Variant of Transcobalamin-II Gene is Linked to Vitamin B12 Deficiency

• Published in: International journal for vitamin and nutrition research Vol. 90; no. 1-2; p. 151
• Main Authors: Al-Batayneh, Khalid M, Salim Al Zoubi, Mazhar, Al-Trad, Bahaa, Hussein, Emad, Al Khateeb, Wesam, Aljabali, Alaa A A, Bodoor, Khaldon, Shehab, Murad, Al Hamad, Mohammad A, Eaton, Greg J, Cornelison, Christopher T
• Format: Journal Article
• Language: English
• Published: Switzerland 01.01.2020
• Subjects: Aged; Case-Control Studies; Humans; Prevalence; Transcobalamins - genetics; Vitamin B 12 - blood; Vitamin B 12 - chemistry; Vitamin B 12 - metabolism; Vitamin B 12 Deficiency - blood; Vitamin B 12 Deficiency - complications; Vitamin B 12 Deficiency - genetics; Transcobalamin; Gastric Intrinsic Factor; Polymorphisms; Vitamin B12 Deficiency
• ISSN: 0300-9831
• DOI: 10.1024/0300-9831/a000536

Vitamin B12 (Cobalamin) deficiency, due to improper internalization of cobalamin, is a metabolic disorder prevalent in impoverished and elderly populations and is associated with megaloblastic anemia and dementia. It has been suggested that mutations in transcobalamin II ( ) or gastric intrinsic factor (GIF) proteins can alter their binding efficiency to cobalamin or reduce the ability of their receptors to internalize them. In this case-control study, the correlation between vitamin B12 deficiency and alternative alleles of and was investigated in a Jordanian population. One hundred individuals with vitamin B12 deficiency (B12 < 200 mg/mL) were enrolled in our study to evaluate the and polymorphisms. The control group (B12 > 200 mg/mL) included 100 individuals. Our results indicated a significant association between the homologous variant of the gene (G776G) and vitamin B12 deficiency, and an intermediate phenotype in heterozygous individuals ( < 0.001, OR = 5.6, 95% CI = 2.95 to 10.63). The gene, however, showed no correlation between the A68G variant and vitamin B12 deficiency ( = 0.2). This study expounds the association of polymorphism with cobalamin levels in a Jordanian population and highlights the necessity of further studies to elucidate the molecular basis and impact of and genes polymorphisms on vitamin B12 deficiency and associated disorders.