Fragile X syndrome
A) is an example of polygenic inheritance.
B) occurs when there is a sudden but permanent change in a segment of DNA.
C) is the most common inherited cause of intellectual disability.
D) occurs more often in females than males because the disorder is X-linked.

Question

Quizplus · Accepted Answer

Fragile X syndrome is caused by a mutation on the X chromosome and is the most common inherited cause of intellectual disability. It is not an example of polygenic inheritance, where multiple genes contribute to a trait, nor is it caused by a sudden but permanent change in a segment of DNA. Although the gene mutation that causes fragile X syndrome is on the X chromosome, it actually occurs more frequently in males than females.

Fragile X Syndrome