Question
A two-and-a-half-year-old girl has had a smaller head circumference than her peers since birth. She is seeking information about microcephaly.
Answer
Microcephaly can be divided into true microcephaly and relative microcephaly. True microcephaly is usually caused by chromosomal abnormalities or exposure to radiation or intrauterine infection during early pregnancy, often accompanied by delayed brain development and intellectual disabilities. Relative microcephaly, on the other hand, is caused by brain injury and atrophy, with a lesser reduction in head circumference.