What birth defects are associated with maternal phenylketonuria (PKU)?

Maternal phenylketonuria (PKU) is a metabolic disorder characterized by the body's inability to metabolize phenylalanine, an amino acid found in many protein-containing foods. When a woman with PKU is pregnant and consumes a diet high in phenylalanine, it can lead to elevated levels of this amino acid, which is teratogenic and can negatively affect fetal development.

The correct choice highlights specific birth defects that are commonly associated with maternal PKU exposure. These include microcephaly, which is a condition where the baby's head is smaller than expected, indicating possible underlying brain development issues. Additionally, intellectual disability (ID) is frequently observed due to the neurotoxicity of elevated phenylalanine levels during critical periods of brain development. Heart defects are also noted as potential complications due to the teratogenic effects of phenylalanine, which might interfere with normal cardiac development in the fetus.

Other options, while they may describe birth defects, do not specifically correlate with the known teratogenic effects of maternal PKU. For example, renal anomalies and intrauterine growth restriction might occur due to various other factors but are not characteristically linked to maternal PKU. Similarly, clefts and limb defects or neural