Microcephaly is associated with infants and children, but it can also occur in adults. In adults, microcephaly can be congenital, meaning it is present at birth or acquired, it develops later in life.  Adults with congenital microcephaly may have had the condition from birth and may have experienced developmental delays and intellectual disabilities as a result. Adults with acquired microcephaly may have developed the condition as a result of a brain injury, infection, or other medical condition.