Ethnicity-Based Genetic Screening

Overview

Some genetic conditions are more common in people whose ancestors came from certain parts of the world. You can choose to have ethnicity-based genetic screening if you and/or your partner are in an ethnic group that has an increased chance of passing on certain genetic conditions. Although the risk of being a carrier for some of these disorders is very low in other populations, it can still occur. Talk to your healthcare provider about the options available to you. If your ethnicity-based genetic screening test result is positive for being a “carrier” you do not have the disorder, but if both parents of a pregnancy are carriers for the same disorder, they do have a risk for children with the disorder as well as a chance of having healthy children. Screening will determine if you are a carrier of genetic traits that can increase your chance of having children with the following disorders:

• Inherited forms of anemia, including diseases known as “Thalassemia”
  • Africa (Black), Southeast Asia, Central American, Mediterranean region
• Sickle cell disease (a hemoglobin disorder)
  • Africa (Black), Southeast Asia, Central American, Mediterranean region
• Cystic Fibrosis
  • European (Caucasian/White), Ashkenazi Jewish (Eastern European Jewish)
• Spinal Muscular Atrophy
  • Varies greatly based on ethnic background
• Tay Sachs
  • Ashkenazi Jewish (Eastern European Jewish)

If you are of Ashkenazi Jewish (Eastern European Jewish) ancestry you may also be offered additional screening tests for:

• Tay Sachs disease
• Other conditions that are more common within the Ashkenazi Jewish population when both parents are of Ashkenazi Jewish ethnicity

Patients of French Canadian ancestry may also be offered additional screening tests for:

• Tay Sachs disease

Being a carrier

A carrier is a person with one working copy and one non-working copy of the same gene for a particular disease. Being a carrier does not generally affect your own health or mean you have or will have the disease.

The only time a baby may inherit the disease:

• When both parents are carriers for the same genetic disease there is a 1 in 4 (or 25%) chance that the baby will have the disease.

The baby will not inherit the disease:

• If neither you nor your partner are carriers
• If only one parent is a carrier, your baby will not have the disease, but may be a healthy carrier just like the parent.

Testing

During a preconception or early prenatal visit, you will answer questions about your and your partner’s ethnicity to determine if you are eligible for ethnicity-based genetic testing. If you want testing, your doctor will order a blood test to identify whether or not you are a carrier. These tests are very accurate, but they will not identify all carriers.

Results

The time it takes to get results varies depending on the test. Your provider will contact you with your results.

A negative result means that you are most likely not a carrier for that particular disease. No further testing is generally needed.

A positive result means that you are a carrier for that particular disease. Follow-up testing will then be offered to baby’s father. If the father also tests positive, you will meet with a genetic counselor to discuss prenatal testing to determine whether or not your developing baby has the condition.

Care Instructions

• Genetic Carrier Screening (Detección de Portadores Genética)
• Ethnicity-Based Genetic Screening
• Cystic Fibrosis: Carrier Screening
• Spinal Muscular Atrophy: What You Need to Know About Carrier Testing
• Spinal Muscular Atrophy: Everything You Need to Know About Being a Carrier
• Thalassemia Genetic Screening
• Tay-Sachs Disease Genetic Testing

Instrucciones De Cuidado

• Pruebas genéticas basadas en la etnia
• Prueba de detección de ser portador de fibrosis quística
• Atrofia Muscular Espinal: Lo que necesita saber sobre las pruebas de portadores
• Atrofia Muscular Espinal: Todo lo que necesita saber si es portador
• Detección genética de talasemia
• Pruebas genéticas para detectar la enfermedad de Tay-Sachs

Making a decision about ethnicity-based screening

Is ethnicity-based genetic screening right for you?

There are generally no prenatal treatments to help lessen the symptoms of ethnicity-based conditions, and the disorders are not curable. For most parents, the test provides reassurance that the baby does not have the genetic disease.

Some people who learn that their baby has one of these diseases may use the information to decide whether or not to continue their pregnancy. Others may use this information to help them prepare for taking care of a child with special medical needs. Your genetic counselor will discuss your options in detail and provide ongoing support.

Is not having these tests right for you?

If you choose to not have testing before or during your pregnancy, your baby can still be tested shortly after he/she is born. The California Newborn Screening Program tests for cystic fibrosis, sickle cell disease, and the thalassemia diseases, along with certain other metabolic and endocrine disorders. Newborn screening is mandatory for all babies born in California.