What is the most common chromosomal pattern found in Turner syndrome?

What is the most common chromosomal pattern found in Turner syndrome?

• A. 46,XX
• B. 46,XY
• C. 47,XYY
• D. 45,X

Answer: (D)

Turner syndrome most often results from the loss of one X chromosome in nearly all cells, called monosomy X. This single missing X leads to haploinsufficiency of X-linked genes, including those like SHOX that influence growth and development, producing the characteristic features such as short stature and gonadal dysgenesis. In the largest portion of cases, this is a 45,X karyotype. Some individuals have mosaic patterns, such as a mix of 45,X and other cell lines (like 46,XX or 46,XY), but the straightforward 45,X pattern remains the most common single chromosomal pattern found. The other listed patterns correspond to normal male or female karyotypes or to trisomy scenarios that are not Turner syndrome.

Turner syndrome most often results from the loss of one X chromosome in nearly all cells, called monosomy X. This single missing X leads to haploinsufficiency of X-linked genes, including those like SHOX that influence growth and development, producing the characteristic features such as short stature and gonadal dysgenesis. In the largest portion of cases, this is a 45,X karyotype. Some individuals have mosaic patterns, such as a mix of 45,X and other cell lines (like 46,XX or 46,XY), but the straightforward 45,X pattern remains the most common single chromosomal pattern found. The other listed patterns correspond to normal male or female karyotypes or to trisomy scenarios that are not Turner syndrome.