Is Down syndrome hereditary?
Jul 08, 2025
Source: Cainiu Health
Dr. Zhou Xiaofeng
Introduction
In general, Down syndrome can be hereditary, although heredity is not absolute. Couples with a family history of Down syndrome or who have previously given birth to a child with the condition should undergo genetic counseling and prenatal diagnosis, such as chromosomal karyotype analysis, when planning a pregnancy, in order to assess the reproductive risk. Meanwhile, pregnant women should receive regular prenatal checkups, avoid exposure to harmful substances, and reduce the likelihood of fetal illness.
Generally, Down syndrome can be hereditary, but inheritance is not absolute. Detailed analysis is as follows:
Down syndrome has a certain hereditary tendency, but such inheritance is not absolute. Most cases of Down syndrome are sporadic, caused by nondisjunction of chromosome 21 during gamete meiosis, and are not directly related to parental genetic material. However, in a few cases, Down syndrome is associated with genetic factors. For example, if one parent carries an abnormal chromosome such as a balanced translocation involving chromosome 21, they may pass the abnormal genetic material to their offspring, increasing the risk of the child being affected. Even with such a genetic predisposition, however, offspring will not necessarily develop the condition, as its occurrence is also influenced by multiple other factors.
Couples with a family history of Down syndrome or who have previously had an affected child should seek genetic counseling and undergo prenatal diagnosis, such as karyotype analysis, before planning a pregnancy to assess reproductive risks. Meanwhile, pregnant women should attend regular prenatal checkups, avoid exposure to harmful substances, and reduce the likelihood of fetal abnormalities.
