Which population is at higher risk for spina bifida due to genetic variation affecting ability to absorb folic acid?

• A. High-income individuals
• B. Genetic variation affecting folic acid absorption
• C. Adults without children
• D. Paternal age over 50

Answer: (B)

Folate is essential for neural tube closing early in fetal development. When a genetic variation affects how folic acid is absorbed or metabolized, some individuals cannot make enough available folate even if their intake is normal. This reduced folate availability during the critical early weeks increases the risk of neural tube defects like spina bifida in the developing fetus. Therefore, populations carrying such genetic variation are at higher risk because the body's ability to supply folate for rapid cell division and DNA synthesis is compromised.

The other options don’t directly tie to folate metabolism or neural tube closure. High income, being an adult without children, or paternal age over 50 aren’t inherently related to a genetic difference in folic acid absorption, so they don’t explain the increased risk in this context.