Down Syndrome and Congential Heart Defects

Dear Ask The Doctor: Hi my name is Keisha and I am expecting my first child..I'm 19.3 weeks pregnant and I went and got my first ultrasound the other day. The doctor told me my baby has a congential heart defect and that it may be associated with Down Syndrome. Nobody in my family nor the father's family has Down Syndrome or any severe medical problems and I was wondering how likely could my child have Down Syndrome...what are the statistics?

Dear Keisha:

Down syndrome is a genetic disorder that causes lifelong mental retardation, developmental delays and other problems. Down syndrome varies in severity, so developmental problems range from moderate to serious. This is considered the most common genetic cause of severe learning disabilities in children, occurring in one in every 700 to 800 infants.

The cause of Down syndrome is one of three types of abnormal cell division involving chromosome 21. All three abnormalities result in extra genetic material from chromosome 21, which is responsible for the characteristic features and developmental problems of Down syndrome. Most cases of Down syndrome aren't inherited. They're caused by a mistake in cell division during the development of the egg, sperm or embryo.

In my opinion at this time of your gestational age, Results of the ultrasound should be paired with blood tests that measure levels of pregnancy-associated plasma protein-A (PAPP-A) and a hormone known as human chorionic gonadotropin (HCG). Abnormal levels of PAPP-A and HCG may indicate a problem with the baby and might confirm and rule out definitely the diagnosis of Trisomy 21 or Down Syndrome. I wish you the best.