________, a common cause of intellectual disability, is caused when a tip of the X chromosome breaks off.
A)Trisomy 13
B)Down syndrome
C)Fragile X syndrome
D)Trisomy 18

Question

Quizplus · Accepted Answer

Fragile X syndrome is caused by a mutation in the FMR1 gene on the X chromosome, which causes a part of the chromosome to become fragile and break off. This leads to a decrease in the amount of a protein called FMRP, which is important for brain development, and can result in intellectual disability, as well as other symptoms such as social and communication difficulties and sensory sensitivities. Trisomy 13, Down syndrome, and Trisomy 18 are all genetic conditions caused by the presence of an extra chromosome, rather than a mutation on a specific chromosome.

________, a Common Cause of Intellectual Disability, Is Caused When