How can genetic polymorphisms influence toxic responses to chemicals?

How can genetic polymorphisms influence toxic responses to chemicals?

• A. Genetic variations in metabolism enzymes (CYPs, NAT, GST), transporters, and DNA repair can alter internal dose and susceptibility.
• B. They only influence cancer risk, not acute toxicity.
• C. They always protect against toxicity.
• D. They have no effect on pharmacokinetics.

Answer: (B)

Genetic polymorphisms affect toxic responses by changing how a chemical is absorbed, distributed, metabolized, and eliminated, as well as how well DNA damage is repaired. Variants in metabolism enzymes such as cytochrome P450s, N-acetyltransferases, and glutathione S-transferases can speed up or slow down activation or detoxification of chemicals, altering the internal dose that reaches target tissues and the formation of reactive metabolites. Transporter gene variants can modify tissue uptake and excretion, further shifting internal exposure. Differences in DNA repair capacity influence how effectively cellular damage from chemicals is fixed, affecting susceptibility to adverse effects like cancer. Together, these polymorphisms create individual variability in both acute and chronic toxic outcomes, not just long-term cancer risk. So, while some polymorphisms may influence cancer risk, they also impact immediate toxicity by altering pharmacokinetics (how much of the chemical and its metabolites reach the target) and pharmacodynamics (the tissue effects), and they can even increase susceptibility to acute toxic reactions.

Genetic polymorphisms affect toxic responses by changing how a chemical is absorbed, distributed, metabolized, and eliminated, as well as how well DNA damage is repaired. Variants in metabolism enzymes such as cytochrome P450s, N-acetyltransferases, and glutathione S-transferases can speed up or slow down activation or detoxification of chemicals, altering the internal dose that reaches target tissues and the formation of reactive metabolites. Transporter gene variants can modify tissue uptake and excretion, further shifting internal exposure. Differences in DNA repair capacity influence how effectively cellular damage from chemicals is fixed, affecting susceptibility to adverse effects like cancer. Together, these polymorphisms create individual variability in both acute and chronic toxic outcomes, not just long-term cancer risk.

So, while some polymorphisms may influence cancer risk, they also impact immediate toxicity by altering pharmacokinetics (how much of the chemical and its metabolites reach the target) and pharmacodynamics (the tissue effects), and they can even increase susceptibility to acute toxic reactions.