The existence of 47 rather than the typical 46 chromosomes is characteristic of
A) Turner's syndrome.
B) PKU.
C) Tay-Sachs disease.
D) Down syndrome.

Question

Quizplus · Accepted Answer

Down syndrome is caused by the presence of an extra copy of chromosome 21, resulting in a total of 47 chromosomes instead of the typical 46. Turner's syndrome (A) is characterized by a missing or incomplete X chromosome, resulting in 45 chromosomes. PKU (B) and Tay-Sachs disease (C) are both caused by genetic mutations but do not involve changes in the number of chromosomes.

The Existence of 47 Rather Than the Typical 46 Chromosomes