Antiepileptic medication during pregnancy: does fetal genotype affect outcome?

Area of Science:

• Pharmacology
• Developmental Biology
• Genetics

Background:

• Congenital abnormalities and childhood developmental impairments are linked to fetal exposure to antiepileptic drugs (AEDs).
• Pregnancy registries indicate valproate exposure is associated with a higher frequency of major congenital malformations (MCMs) and cognitive impairments compared to other AEDs.
• Placental drug transporters, including P-glycoprotein (P-gp), multidrug resistance protein (MRP) 1, and breast cancer resistance protein (BCRP), are crucial in protecting the fetus from maternal medications.

Purpose of the Study:

• To investigate the role of genetic variations in placental drug transporters in mediating fetal exposure to AEDs.
• To understand how these variations influence the risk of teratogenicity and developmental issues in children exposed to AEDs during pregnancy.
• To identify genetic factors that could aid in assessing fetal risks and inform genetic counseling.

Main Methods:

• Review of existing pregnancy registry data on AED exposure and congenital malformations.
• Analysis of the function and location of key placental drug transporters (P-gp, MRP1, BCRP).
• Exploration of the impact of genetic variations (haplotypes) in these transporters on AED efflux and fetal exposure.

Main Results:

• Valproate exposure is linked to increased congenital malformations and cognitive deficits.
• Placental drug transporters (P-gp, MRP1, BCRP) located in the syncytiotrophoblast can efflux xenobiotics, protecting the fetus.
• Genetic variations in these transporters may alter their activity and influence fetal AED exposure levels.

Conclusions:

• Genetic variations in placental drug transporters play a role in fetal exposure to AEDs.
• Identifying susceptible or protective haplotypes could improve risk assessment for congenital abnormalities.
• This knowledge can enhance genetic counseling for pregnant individuals taking AEDs.