Genetics of CNS Malformations

Chromosomal abnormalities in oocytes and sperms reach 18-19% and 3-4% respectively. Not surprisingly then, about 1 in 13 conceptions results in chromosomally defective conceptus, while about 50% of first trimester spontaneous abortions are associated with chromosomal abnormalities.Clinically significant chromosomal aberrations occur in 0.65% of all live births, an additional 0.2% ofbabies are born with balanced structural chromosome rearrangements that have implications for reproduction later in life. Between 5.6 and 11 .5% of stillbirths and neonatal deaths havechromosomal defects (1).