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Tetralogy of Fallot conotruncal development — MRCPCH TAS MCQ

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HardEmbryologyTetralogy of Fallot conotruncal developmentMRCPCH TAS

A newborn has cyanosis, a harsh systolic murmur and echocardiography showing ventricular septal defect, overriding aorta and pulmonary stenosis. What embryological process is most likely abnormal?

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Correct answer: E — Neural crest contribution to conotruncal septation

Tetralogy of Fallot is a conotruncal abnormality linked to abnormal neural crest contribution to outflow tract septation. Failure of midgut return causes omphalocele rather than cyanotic heart disease. The pearl is that conotruncal defects should prompt consideration of 22q11.2 deletion.

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