Which condition is most consistent with this karyotype finding, and what is the underlying mechanism?
- A
Klinefelter syndrome, caused by an extra X chromosome in males.
- Bcheck_circle
Down syndrome (trisomy 21), most often caused by nondisjunction during meiosis I in the mother.
- C
Cri-du-chat, caused by chromosome 5 deletion.
- D
Turner syndrome, caused by a missing X chromosome.
Explanation
A third copy of chromosome 21 (trisomy 21) causes Down syndrome and most commonly results from maternal meiosis I nondisjunction.