Question

3 tries left
dr. park has found that her patient, ye - jun, has a defect in a gene on the x chromosome of his 23rd pair, resulting in a deficiency of a protein needed for brain development. ye - jun most likely suffers from __________.
down syndrome
fragile x syndrome
cretinism
fetal alcohol syndrome

Explanation:

Fragile X syndrome is caused by a defect in a gene on the X - chromosome which can lead to a deficiency of a protein important for brain development. Down syndrome is due to an extra copy of chromosome 21. Cretinism is related to thyroid - hormone deficiency. Fetal alcohol syndrome is caused by maternal alcohol consumption during pregnancy.

Answer:

B. fragile X syndrome