The prenatal test is a diagnostic Down syndrome screening tool used during pregnancy in order to know if the unborn child is developing normally. The diagnosis of Down syndrome can be made either before the birth (prenatal) or after the birth (postnatal) of the child. Understanding Down syndrome and its causes can help in diagnosing the condition faster.
Down syndrome causes are genetic in nature, and an abnormal number of chromosomes are the primary cause behind this condition. It is the most common numerical chromosomal anomaly associated with mental retardation, and occurs in 1 in every 600 live births.
Down syndrome symptoms can be mainly noted in people who suffer from the condition. This disorder is one of the most common numerical chromosomal anomalies caused by an extra chromosome 21. The presence of an extra chromosome 21 produces several typical physical features that affect normal cognitive abilities.