May be very discrete. Defective neuronal migration with four, rather than six, layers in the cortex. Failure to thrive. Infantile spasms and seizures. Reduced chances for surviving.
Death occurs usually within the first six years.
Affected children will not grow up to reproductive age. Usually the ultrasound diagnosis is made during the third trimester, and termination is not an option. The first observations of Miller-Dieker syndrome, a type I liss encephaly, were made by Miller in 1963 and Dieker in 1969. This chromosomal defect can be so discrete that DNA analysis is necessary to detect it 5,6 . Only two cases have previously been diagnosed prenatally using ultrasound, both of them by Saltzman 7 .