March 21st, World Down Syndrome Day WDSD, is being illustrated by the mismatched socks pairs, hinting at the meiotic nondisjunction chromosomal errors (NDJ) that result in the Down syndrome condition. An individual diagnosed with Down syndrome has an extra copy of chromosome no. 21, so their cells contain 47 chromosomes instead of the standard 46, leading to ‘trisomy’ causing defects in brain and body functions. According to CDC, Down syndrome is the most common chromosomal disorder, and as an estimated 1 in 700 live births, is characterized by symptoms and disabilities.. A baby with Down syndrome has characteristic facial and physical features such as a flat face, mouth with protruding tongue, and distinct finger gaps. Most importantly such infants are prone to congenital defects, vision and hearing problems, blood cancer, tumours, thyroid issues, and infections overall. There are three main types of Down syndrome conditions: Trisomy 21, Translocation, and Mosaicism, with Trisomy 21 being the most prevalent one (comprising about 95% of Down syndrome cases).
What risk factors other than the mother’s age are crucial?
Generally, the risk factor most commonly associated with Down syndrome is the age of the birthing parent (maternal age) which is scientifically correct in terms of probability as the risk for the mother to bear a Down syndrome child increases to 1/350 by 35 years of age and to 1/100 by 40 years. However, research by CDC has shown that 80% of children with Down syndrome are born to mothers younger than 35, this is because younger women have more babies. Also, a mother’s lifestyle during pregnancy has nothing to do with the increased or decreased chances, as Dr. Rosenbaum says “Nothing you do during your pregnancy will increase your risk or reverse what has already happened,” No matter your risk, Down syndrome occurs before conception. Since maternal age is not the sole determinant of chromosomal aberrations, what other risks remain significant in controlling the nondisjunction errors causing Down syndrome? In terms of risks, parental genetics and history are of crucial impact; and maternal folate metabolization is still under study. In the case of Trisomy 21 and mosaic Down syndrome (mosaicism), the heredity is irrelevant, but the translocation of Down syndrome is found to be passed from parent to child in one-third of the cases. Grand-Maternal consanguinity (mating between blood relatives) is a possible predisposing factor in young mothers to bear babies with Trisomy 21. As per studies older men are known to produce more sperms with aneuploidy (the occurrence of one or more extra or missing chromosomes), so the age of the father is another important factor from a heredity perspective. In terms of genetics and dietary regulation of the mother, folate metabolization is being explored and there isn’t a clear conclusion on the link between the Down syndrome risks and folate metabolization by the mother.
What myths must be busted regarding Down syndrome?
The Global Down Syndrome Foundation has made an effort to educate people on certain fallacies regarding Down syndrome. First of all, a person of any age can have a baby with Down syndrome, even young healthy mothers with healthy lifestyles can have babies with Down syndrome. The diagnostic testing and screening for Down syndrome can be performed before 20 weeks of pregnancy, and any signs of early detection do not pressurize parents to terminate the pregnancy, instead, it effectively assists in determining the caregiving strategies by the professionals, pre and post-natal period. Most effective tests include Cell-free fetal DNA screening, serum screening, nuchal translucency, AFP screening, and fetal anatomy scan.
Individuals with Down syndrome, do not always die at a young age, the average life span for individuals with Down syndrome is approximately 50-60 years. Also, Down syndrome does not run in the families but if the parents already had a child with Down syndrome, the probability of having another is 1 in 100 for Trisomy 21. Not all individuals with Down syndrome are prone to Alzheimer’s, they have normal memory retention, can live independently, can get jobs, can read, write and play sports and are advised to join public schools for training. On the downside, they may face difficulty in bearing children, in certain cases. Interestingly, divorce rates are lower in families of children with Down syndrome and their siblings are documented to show increased tolerance and altruism, with a caregiving aspect in contrast to the typical siblings.