Question

Select the incorrect} match from the following:

• A. 45 + XX — Broad palm with characteristic palm crease
• B. 44 + XXY — Overall feminine development
• C. 44 + XO — Sterile females as ovaries are rudimentary
• D. 44 + XY — Normal male

Hint:

Down syndrome involves an extra chromosome 21 (47 chromosomes), not 45. A total of 45 chromosomes with XX doesn't indicate Down syndrome traits. Always match chromosome count with phenotype clues.

Answer 1

The Correct Option is A

Let’s analyze the human karyotype and character combinations one by one:
(A) 45 + XX indicates a missing chromosome but shows a normal female sex chromosome pattern (XX).
However, the total chromosome number 45 (instead of the normal 46) does not typically describe any known syndrome with the given symptom — broad palm with characteristic palm crease}.
This symptom is typically associated with Down syndrome, which has the karyotype 47 + XY or 47 + XX (trisomy 21), not 45 + XX.
Hence, this match is incorrect.
(B) 44 + XXY refers to Klinefelter syndrome, which indeed presents overall feminine development due to the presence of an extra X chromosome in a genetically male individual.
(C) 44 + XO is Turner syndrome, a condition where females are sterile due to rudimentary ovaries. This is a correct match.
(D) 44 + XY is the normal male karyotype (autosomes 44 + XY sex chromosomes), hence correct.