An amniocentesis or amniotic fluid test has identified a defect on the short arm of the 21st pair of chromosomes in a developing embryo. It is likely that this child will have
A) Tay-Sachs disease.
B) Fragile X syndrome.
C) Tourette's disorder.
D) Down syndrome.

Question

Quizplus · Accepted Answer

The defect on the short arm of the 21st pair of chromosomes is a characteristic of Down syndrome. Tay-Sachs disease is caused by a defect on chromosome 15, Fragile X syndrome is caused by a defect on the X chromosome, and Tourette's disorder does not have a known genetic cause.

An Amniocentesis or Amniotic Fluid Test Has Identified a Defect