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Neural tube closure defect — MRCPCH TAS MCQ

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EasyEmbryologyNeural tube closure defectMRCPCH TAS

A newborn has a lumbosacral lesion containing meninges and neural tissue. The mother did not take folic acid before conception. What is the most likely embryological mechanism?

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Correct answer: A — Failed posterior neuropore closure

Myelomeningocele results from failed neural tube closure, particularly at the posterior neuropore. Failed ureteric bud branching would cause renal tract anomalies rather than an open spinal lesion. The pearl is that periconceptional folic acid reduces the risk of neural tube defects.

Reference: Gray's Anatomy; Nelson Textbook of Pediatrics; RCPCH Theory examination syllabi