Prenatal Diagnosis

Other Genetic Diseases

Signs and Symptoms
Diagnosis
Treatment

Signs and Symptoms

Depending on your family history, ethnicity and heritage, your developing baby may be at risk for one of the following genetic conditions:

1. Canavan Disease — This condition is most common in people of Ashkenazi Jewish ancestry, with a carrier incidence of 1 in 40. Canavan disease is a central nervous system disease that is usually fatal in childhood, with a few people surviving to adulthood. This disease is the result of a substance that destroys the central nervous system over time. There is presently no effective treatment for Canavan disease.

2. Fragile X Syndrome — The Fragile X syndrome is not specific to a certain ethnic background. It is an inherited condition that can cause a range of intellectual and behavioral problems, from learning disabilities to mental retardation to autism. While Fragile X syndrome tends to be more severe in boys, it occurs in both males or females. It can be passed on to family members by individuals who have no signs of the syndrome. Review of your family history with a genetic counselor may help determine if Fragile X carrier testing is indicated.

3. Sickle Cell Disease — This condition is most common in persons of African-American, African, Mediterranean, Hispanic and South American ancestry, with the carrier risk ranging from 1/10 to 1/40, depending on your ethnic background. Sickle cell disease is caused by a variant hemoglobin that changes the shape of the red blood cells. This causes anemia, severe pain, a tendency toward infection, and other serious health problems. Frequent blood transfusions and infection preventing antibiotics are available treatment. UCSF doctors were the first to develop a prenatal test for sickle cell anemia.

4. Tay Sachs Disease — People of both Ashkenazi Jewish and French Canadian ancestry have the greatest chance of being carriers of Tay Sachs disease, about 1/30 versus 1/250 in the general population. The disease results from a build up of certain substances in the brain, and is fatal in early childhood. There is presently no effective treatment for Tay Sachs disease.

5. Thalassemia — Individuals of Mediterranean, Southeast Asian and African ancestry have the greatest chance — 1 in 3 and 1 in 30, respectively — of being carriers for thalassemia. In general, this group of blood disorders affects a person's ability to produce hemoglobins, the protein in our blood that carries oxygen and nutrients to all parts of the body. In severe cases, children with thalassemia may not survive. Others have anemia, bone growth problems and liver and spleen involvement. Blood transfusions may be needed for treatment. UCSF doctors were the first to develop a prenatal test for thalassemia.

Some genetic disorders are more common in certain ethnic groups. People who carry genes for these disorders may not have symptoms. However, if both parents are carriers of the same abnormal gene, the chance of having an affected child is 1 in 4, or 25 percent, for each pregnancy. A special blood test, called a carrier test, may be able to tell if you carry such a trait.

Reviewed by health care specialists at UCSF Children's Hospital.
Last updated August 31, 2007