Which of the following genetic disorders is caused by the presence of an extra copy of chromosome 21?
A)Down syndrome
B)Turner syndrome
C)sickle-cell anemia
D)phenylketonuria

Question

Quizplus · Accepted Answer

Down syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21. This extra genetic material can lead to intellectual disability, developmental delays, characteristic physical features, and other medical problems. Turner syndrome is caused by a missing or partially missing X chromosome, sickle-cell anemia is caused by mutations in the HBB gene that codes for hemoglobin, and phenylketonuria is caused by mutations in the PAH gene that codes for an enzyme involved in breaking down the amino acid phenylalanine. None of these conditions are caused by an extra copy of chromosome 21.

Which of the Following Genetic Disorders Is Caused by the Presence