Question
A young girl of 12 years of age comes into her provider’s office for her health maintenance examination. The provider notes that she is overall healthy and has met all of her cognitive and motor milestones, but she has always been below average on her growth chart and is much shorter than other children her age. During today’s visit, her mother notes that she has not yet started menses and has little to no breast development. What is the most likely finding on the karyotype of this girl?
| A. |
45, X
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| B. |
47, XXY
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| C. |
45, X/ 46, XX
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| D. |
46, XX with trisomy 21
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Show Answer
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Correct Answer � C
Explanation
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Ans. C
- Trisomy 21 is not the correct answer; the question does not note any of the characteristic facial features associated with trisomy 21. Also, patients with trisomy 21 have significant cognitive impairment and learning disabilities, and the question notes that the girl has met all of her cognitive milestones. Turner syndrome patients are typical of normal intelligence.
- 47 XXY would be Klinefelter syndrome. If the patient had Kleinfelter syndrome, you would see male external genitalia with small testicles and gynecomastia. The patient is noted to be female and to have little breast development. Turner syndrome patients typically have female external genitalia.
- 45, X is a good answer given the fact that this genetic makeup corresponds with Turner syndrome, which can result in amenorrhea and short stature. However, this is not the best answer in patients who are 45, X non-mosaic turner syndrome will likely have a great deal of other associated health problems such as kidney and cardiac issues such as horseshoe kidney, bicuspid aortic valve, and coarctation of the aorta.
- 45, X/ 46, XX is the correct answer. The patient in the question is overall healthy with no comorbid conditions that would be seen in 45, X. Turner syndrome but do exhibit the short stature and amenorrhea that can be seen in mosaic Turner syndrome.
