The maternal age effect describes the exponentially increasing risks for numerical chromosomal abnormalities among a prospective mother's gametes as she ages. This increase reflects the overall increase in the rate of nondisjunction with maternal age.[citation needed]
However, paternal age does also have an effect.. A research study conducted by Fisch et al.[1] showed that paternal age has a negligible effect up to the age of 35. Over the age of 35, a paternal effect is seen in conjunction with a maternal age of over 35 and was most pronounced when maternal age was 40 or over. In this group, the paternal age effect was 50%. This trend is common to all non-inherited familial causes of genetic disease. This is because a woman's ova only divide a total of 24 times throughout life, the first 23 of which happen in utero, whereas men's sperm divide continuously throughout life, leading to gradually increasing copy errors. Trisomy 21 derived from maternal age effect is due to an error when the egg splits.
Sources
- ^ The Influence of Paternal Age on Down Syndrome
See also
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