Which of the following is a clinical manifestation of vitamin D deficiency in infants?

Vitamin D deficiency in infants typically leads to rickets, a condition characterized by impaired mineralization of the growing bones. One of the notable clinical manifestations of rickets includes delayed closure of fontanelles, particularly the anterior fontanel. This occurs because vitamin D is essential for calcium and phosphorus metabolism, which play a critical role in bone development and health. When vitamin D levels are insufficient, it negatively affects the growth and mineralization of the infant's bones, leading to delayed closure of the fontanelles.

While craniosynostosis, absence of the Moro reflex, and severe jaundice can be seen in various pediatric conditions, they are not directly associated with vitamin D deficiency. Craniosynostosis is a premature fusion of cranial sutures not related to vitamin D levels. The Moro reflex is a neurological response present in infants rather than a direct result of nutritional deficiencies. Severe jaundice is predominantly related to liver function and hemolysis in newborns, rather than being a manifestation of vitamin D deficiency. Therefore, delayed fontanel closure distinctly signifies issues with bone metabolism associated with inadequate vitamin D levels, making it the correct choice in this context.