What is a potential consequence of excessive bilirubin buildup in infants?

Bilirubin buildup in infants, particularly when it reaches excessive levels, can lead to a condition known as neonatal jaundice. One of the severe complications associated with untreated or prolonged high levels of bilirubin is kernicterus, which can result in permanent neurological damage. This damage often manifests in various ways, including potential intellectual disabilities. The accumulation of bilirubin can disrupt brain function, affecting cognitive development and leading to various developmental delays and disorders.

The other options do not reflect the impact of excessive bilirubin levels. For instance, improved reflexes or faster developmental milestones are not associated with higher bilirubin levels, as such conditions are indicative of healthier neurological function. Enhanced metabolic function is also not a consequence of bilirubin excess; rather, bilirubin buildup signals metabolic dysfunction related to liver processing in infants. Hence, the correct choice highlights a significant potential outcome of this medical condition.