Among the most well-known chromosomal abnormalities in people, Down’s syndrome is brought on by a trisomy of chromosome 21. The syndrome has an impact on the majority of bodily functions, resulting in a number of distinctive clinical traits, notably learning disabilities, short height, a flattened face, a flattened nasal bridge, and a prominent tongue (MacLennan, 2020). Additionally, there is a higher chance of developing additional illnesses in people with Down’s syndrome (MacLennan, 2020). However, it is noteworthy that the risks of Down’s syndrome recurrence with following pregnancies depend on age and number of pregnancies.
Among doctors, it is common knowledge that once a mother’s age exceeds 30 years, her probability of having a child with Down’s syndrome rises sharply. A 30-year-old mother has a 1 in 1000 chance of giving birth to a child with Down’s syndrome (MacLennan, 2020). When reducing the risk of 1 in 1000 by three, it is possible to calculate an increasing likelihood that a woman will give birth to a child with Down’s syndrome with every five years beyond the age of 30 (MacLennan, 2020). Suppose the woman is younger than 35 years old, and the chromosomal anomaly was present in previous pregnancies. In that case, there is a 1 in 100 chance that the pregnancy will result in another Down’s syndrome diagnosis for the child (MacLennan, 2020). Future parents can choose to have a Down’s syndrome test as part of their prenatal treatment. According to current standards, a combined test should be used to assess for Down’s syndrome during the first trimester.
Hence, trisomy of chromosome 21 results in Down’s syndrome, one of the most well-known chromosomal disorders in humans. Yet, the rising likelihood of having a pregnancy with a child who is at risk of Down’s syndrome depends on the age of the mother and previous pregnancies with the fetus developing Down’s syndrome. In the first case, a woman over 30 years old has a higher chance of having a child with this condition. Furthermore, a woman who previously had a child with this syndrome has a 1% chance of recurring cases.
Reference
MacLennan, S. (2020). Down’s syndrome. InnovAiT, 13(1), 47-52.