Jerry was born with a round face,flattened skull,short limbs,and retardation of motor and mental abilities.The doctors told Jerry's parents that this is because he has an extra copy of chromosome 21.Which of the following chromosomal abnormalities does Jerry have?
A)Phenylketonuria
B)Turner syndrome
C)Sickle-cell anemia
D)Down syndrome

Question

Quizplus · Accepted Answer

Jerry's symptoms are consistent with Down syndrome, which is caused by an extra copy of chromosome 21. Phenylketonuria is caused by a single gene mutation, Turner syndrome is characterized by a missing or partially missing X chromosome, and sickle-cell anemia is caused by a mutation in the beta-globin gene. None of these conditions are related to Jerry's symptoms.

Jerry Was Born with a Round Face,flattened Skull,short Limbs,and Retardation