Which of the following anomalies can be classified as a malformation?

• A. Neural tube defect
• B. Achondroplasia
• C. Congenital hip dislocation
• D. Hemangioma

Answer: (A)

Malformations are intrinsic errors in how a structure forms during early embryonic development. Neural tube defects illustrate this well, arising when the neural tube fails to close properly in early gestation (around the first month), which leads to conditions like spina bifida or anencephaly. These are problems with formation itself, not due to later forces or external factors.

In contrast, congenital hip dislocation is usually a deformation from mechanical forces in utero, not a primary developmental malformation of the structure. Achondroplasia is a skeletal dysplasia from a genetic mutation that affects cartilage growth, a different abnormal development process. Hemangioma is a vascular proliferation, not a malformation of the embryonic structure.

So the neural tube defect best fits the classification as a malformation.