Question
What is the probability of a child having Down Syndrome?
Answer
Down Syndrome, also known as Trisomy 21, is caused by an extra chromosome in the 21st pair of a fetus. Prenatal screening can detect the levels of alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG) in the pregnant woman’s serum, combined with the woman’s age, weight, and gestational age to calculate the risk of the fetus having Down Syndrome. The critical value for the screening is 1 in 275, with values above indicating a high risk and below indicating a low risk. For the general population under the age of 37, the incidence rate of Down Syndrome is approximately 1 in 750. If the screening results indicate a high risk, it is recommended to undergo amniocentesis for a more accurate diagnosis. Even if the screening results indicate a high risk, it does not necessarily mean that the fetus has Down Syndrome. However, for safety’s sake, it is usually recommended to conduct further tests. Children with Down Syndrome often suffer from severe intellectual disabilities and deficiencies in life skills, and may also have complex cardiovascular diseases. They require long-term family care, which can impose significant emotional and economic burdens on families.