**Question:** Closure of the anterior fontanelle is delayed in all except –

A. neonates with Down syndrome
B. premature infants
C. infants with craniosynostosis
D. infants with severe malnutrition

**Core Concept:**

The anterior fontanelle, also known as the soft spot on a baby's head, is a temporary opening between the bones of the skull in infants. In a growing child, the fontanelles close as the skull bones fuse together. Delayed closure of the anterior fontanelle can indicate certain conditions, such as malnutrition or craniosynostosis, which is premature fusion of skull sutures.

**Why the Correct Answer is Right:**

Answer D, "infants with severe malnutrition," is incorrect because malnutrition generally leads to growth retardation, not delayed closure of fontanelles. In contrast, delayed closure is more commonly associated with conditions that affect skull development, such as those involving the skull bones or hormonal influences.

**Why Each Wrong Option is Incorrect:**

A. Neonates with Down syndrome (trisomy 21): While Down syndrome can affect overall growth, it also involves specific craniofacial abnormalities, including flattened fontanelles, which are often larger and persist longer than in typically developing infants.

B. Premature infants: Delayed closure of fontanelles in premature infants is a normal finding due to immature skull development and smaller head size, as they catch up with their peers over time.

C. Infants with craniosynostosis: Craniosynostosis is a condition where premature fusion of skull sutures occurs, which leads to delayed closure of fontanelles.

**Clinical Pearl:**

A neonate with normal development and no congenital anomalies should have a fontanelle that closes within the first few months of life. However, in certain conditions like Down syndrome and craniosynostosis, fontanelles may remain larger and persist longer. This is an important aspect to consider in clinical practice when evaluating a child's head growth and development.