Many polymorphisms have been reported for this gene, also known as MDR1.
ABCB1, also called CD243, codes for a cell membrane protein, P-glycoprotein(permeability glycoprotein, abbreviated as P-gp), that transports chemicals out of cells. It is expressed in various tissues, including the blood–brain barrier. Two SNPs are discussed frequently; note that they may be in linkage disequilibrium:
- rs2032582, also known as G2677T, is mentioned by:
- [PMID 17120199] The G2677T/A (T) variant in exon 21 is at a 2.6 fold higher risk of developing lung cancer. Another SNP, C3435T (in exon 26) may modulate the influence. (G2677 is also known as Ala893Thr.) The highest risk for lung cancer (up to 20 fold higher risk) is seen for 2677(T;T) plus heterozygous 3435(C;T) carriers.
- rs1045642, also known as C3435T, is mentioned by:
- [PMID 17185560] A "Silent" Polymorphism in the MDR1 Gene Changes Substrate Specificity.
- [PMID 17190370] (R)-lansoprazole (Prevacid) concentrations are significantly increased in CYP2C19 extensive metabolizers with ABCB1 C3435T C allele.
- [PMID 15536457] In a Korean population, plasma concentrations of fexofenadine (Allegra) were 17% lower in 2677AA/3435CC subjects and 47% higher in the 2677TT/3435TT subjects compared to 2677GG/3435CC subjects.
- [PMID 11994059] In contrast, in this study no association was observed between the C3435T polymorphism and fexofenadine plasma or urine concentrations in a German Caucasian population.
A general article on MDR1 SNPs is:
- [PMID 17187507] Ethnicity-related polymorphisms and haplotypes in the human ABCB1 gene.