How can genetic syndromes be identified?
There are two ways we go about identifying genetic syndromes prenatally. We take a careful family history of both prospective parents. Also, we offer carrier testing, which involves a blood test that determines whether either partner carries a specific faulty gene, based on ethnic group.

Family History
When taking a family history, we try to identify all individuals in the family of both prospective parents who have a medical condition that could be hereditary, and, thus, affect the pregnancy. There are three major patterns of inheritance:

1. Autosomal recessive disorders occur when both parents, who are apparently healthy, are carriers for the same disorder. Examples are cystic fibrosis and sickle cell disease. Couples who have an affected son or daughter are at greatest risk. There is a 25% likelihood that their subsequent children will have the same disorder.
2. X linked disorders affect boys more than girls. Examples include muscular dystrophy, hemophilia, and fragile X mental retardation. If the genetic defect is passed from the mother, half of her sons will be affected and half of her daughters will be carriers. Carrier daughters may have milder manifestations of the disease.
3. Autosomal dominant disorders are passed from parent to child. If either parent has one of these conditions, each of their offspring (both male and female) has a 50% chance of inheriting the same disorder. However, the severity of the disorder in affected individuals is frequently unpredictable.

Carrier Testing
In most ethnic groups some genetic disorders occur frequently enough that we can offer screening to couples that wish to pursue this, even in the absence of a family history of the condition. We offer different tests based on ethnic background. For example: