Mother's Age: 30 years 31 years 32 years 33 years 34 years 35 years 36 years 37 years 38 years 39 years 40 years 41 years 42 years 43 years 44 years 45 years There is no evidence of a man with Down syndrome fathering a child. I am 26 this is my second pregnancy...1st normal. For most women, your Down syndrome risk is based mostly on your age. Down syndrome (DS) originates, in most of the cases (95 %), from a full trisomy of chromosome 21. Fifteen to thirty percent of women with trisomy 21 are fertile and they have about a 50% risk of having a child with Down syndrome. If the chromosomes of both parents are OK, then the recurrence risk is about 1% if the mother is under 40 years of age and about twice that for a mother who is 40 and over. Having a first-degree family member with Parkinson’s raises the risk to 3 percent . It’s rare for these types of hereditary diseases to suddenly appear in someone with no family history of them. True, and Down syndrome is not a genetic disease and has nothing to do with family history. This calculator will let you know your own personalized risk. If either parent is a 'balanced translocation' carrier to chromosome 21 (21/21) then the recurrence risk is 100%. Therefore, prenatal screening and genetic counseling are important. [Selikowitz, M Down Syndrome: The facts, 2nd Ed., 1997, p. 177] From these graphs, it can be seen that AFP, uE3 and PAPP-A values below 0.86 MoM, 0.83 MoM and 0.64 MoM respectively and NT, inhibin-A and free ß-hCG values above 1.46 MoM, 1.54 MoM and 1.67 MoM respectively will tend to increase the risk of Down’s syndrome above the background risk while values in the opposite directions will tend to decrease the risk below the background risk. Having a family history of Parkinson’s disease may increase the risk that you will get it. People with Down syndrome rarely reproduce. Down syndrome is caused when one's genetic code has an extra copy of chromosome 21 (or part of one).Since chromosomes normally come in pairs, this is often referred to as trisomy 21. Full trisomy 21 and mosaicis … Had the level II ultrasound and they saw sign of down syndrome..femur was shorter that should be. I had the AFP test came back 1 in 12 chance of baby having down syndrome( 10% chance of the baby having down syndrome 90% normal). The remaining cases are due to either mosaicism for chromosome 21 or the inheritance of a structural rearrangement leading to partial trisomy of the majority of its content. Had amniocentesis and came back positive for down syndrome.