A13-month-old child is noted to be at the 25th percentile for weight, the 10th percentile for height, and less than the 5th percentile for head circumference. she was born at term. she was noted to have a small head at birth, to be developmentally delayed throughout her life, and to have required cataract surgery shortly after birth. she currently takes phenobarbital for seizures. which of the following would most likely explain the child’s small size?
a) congenital cytomegalovirus (cmv) infection
b) downsyndrome 
c) glycogen storage disease type ii 
d) congenital hypothyroidism
e) craniopharyngioma

A) Congenital cytomegalovirus (CMV) infection

Explanation:

Cytomegalovirus (CMV) is a common virus that can infect most people. ... However, infection with this virus is of concern in pregnant women and people with a depressed immune system. Cytomegalovirus is from the herpes simplex virus family.

The most common clinical signs are petechiae, jaundice and hepatomegaly. Neurological signs are not specific, observing microcephaly, and newborns may have hypotonia with drowsiness), difficulty in sucking, spasticity, hemiparesis or convulsions. Other signs can also be observed as: Chorioretinitis, lung problems, splenomegaly and low birth weight.

Microcephaly can occur by neural migration when infection occurs during the first trimester of pregnancy.