Does maternal MDR1 C1236T polymorphism have an effect on placental arsenic levels?

• This was the first study evaluating the effect of MDR1 C1236T polymorphism on placental arsenic levels.
• Placental arsenic levels of MDR1 C1236T variant mothers were found higher than those of wild type.
• Fetuses of mothers with TT genotype may be more susceptible to arsenic toxicity.

To detect whether maternal MDR1 C1236T polymorphism has an effect on placental arsenic levels, 112 mother–placenta pairs were examined. Venous blood samples from mothers were collected to investigate the C1236T polymorphism which was detected by standard PCR–RFLP technique. Placentas were collected to measure arsenic levels by GF-AAS. The MDR1 C1236T genotype frequencies of mothers were found as 30.3% homozygote typical (CC), 51.8% heterozygote (CT) and 17.9% homozygote atypical (TT). The mean placental arsenic level was 62.36 ± 30.43 μg/kg. It was observed that the placental arsenic concentrations were higher in mothers with TT genotype than those with CC and CT genotypes, but this was not statistically significant (p = 0.702). This finding was indicated that fetuses of mothers with TT genotype may be more susceptible to arsenic toxicity as compared to those of with CC and CT genotypes. We believe that this difference warrant further studies with larger study subjects.