Q. What is the difference between a chromosomal abnormality and a genetic abnormality?
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| Dr. Gerald Prescott |
Answer provided by Gerald H. Prescott, D.M.D., P.A., F.A.C.M.G., Clinical Director of Northwest Perinatal Center at Providence St. Vincent Medical Center: A genetic abnormality is essentially defined as a mutation in DNA, the natural substance that forms genes and chromosomes. In the case of a genetic DNA abnormality, the chromosome is normal, but the DNA inside of it is not. Genetic abnormalities (such as hemophilia, cystic fibrosis, muscular dystrophy, color blindness and Huntington’s chorea) result when DNA mutations are passed on from a parent.
A chromosomal abnormality (such as Down Syndrome), on the other hand, is the result of extra chromosomes or missing chromosomes in the cell nucleus. Chromosome problems are present from the moment of conception on, and therefore are the result of an aberration in either the egg or the sperm.
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February 2002
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