Sarah, age 14 months, was born with microcephaly, small head (cranium) size and is severely retarded. Chromosome analysis indicates that she lacks a piece of one of her number 13 chromosomes. Her parents come in to have their chromosomes analyzed to see whether one of them may have been a carrier for a translocation that could result in children affected like Sarah or children with other chromosomal, anomalies.

Summarized question: What causes child to be born with microcephaly?