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Turner syndrome mosaicism — MRCPCH TAS MCQ

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ModerateGeneticsTurner syndrome mosaicismMRCPCH TAS

A 13-year-old girl has short stature, delayed puberty and a webbed neck. Echocardiography shows coarctation of the aorta. Which chromosomal result is most consistent with the diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — 45,X or mosaic 45,X/46,XX

The phenotype is typical of Turner syndrome, which may be monosomy X or mosaic 45,X/46,XX. Klinefelter syndrome is 47,XXY and would present in a phenotypic male. The clinical pearl is that Turner syndrome is associated with left-sided cardiac lesions and renal anomalies.

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