Williams syndrome microdeletion — MRCPCH TAS MCQ

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HardGeneticsWilliams syndrome microdeletionMRCPCH TAS

A 6-year-old has developmental delay, an outgoing social manner, hypercalcaemia and supravalvular aortic stenosis. What is the most likely genetic abnormality?

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Correct answer: B — 7q11.23 microdeletion involving elastin

Williams syndrome is caused by a 7q11.23 microdeletion including ELN, explaining the arteriopathy. A 22q11.2 deletion causes conotruncal defects, hypocalcaemia and T-cell abnormalities rather than hypercalcaemia with supravalvular aortic stenosis. The pearl is that microdeletion syndromes often combine developmental, vascular and endocrine clues.

Reference: Nelson Textbook of Pediatrics; RCPCH Theory examination syllabi; The Science of Paediatrics MRCPCH Mastercourse