A 12-year-old girl is evaluated for short stature. She is 130 cm tall (below 3rd centile) and has not shown any signs of pubertal development. On examination, she has a webbed neck, widely spaced nipples, and a low posterior hairline. Her karyotype is likely to reveal which abnormality?
- A 45,X ✓
- B 47,XXY
- C Trisomy 21
- D 47,XXX
Correct answer: A. 45,X
Explanation
Turner syndrome is caused by complete or partial monosomy X (45,X). The classic features include short stature, webbed neck, widely spaced nipples (shield chest), low posterior hairline, and primary ovarian failure with absent puberty. Short stature is the most consistent feature and is due to haploinsufficiency of the SHOX gene. Growth hormone therapy is used to improve final adult height. Karyotype confirmation is essential as mosaic forms exist.
Reference: Nelson Textbook of Pediatrics, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.