Carrier Screening in AJ population

Question 1

What is the overall carrier rate of “Jewish Genetic Disorders” in the AJ population?

Answer 1

1 in 4 to 1 in 5 Ashkenazi Jews are carriers for one of these disorders

Question 2

Importance of the history of Tay-Sachs and the carrier screening program

Answer 2

Over 30 years ago, the development of an accurate and reliable biochemical test led to a successful carrier screening program for Tay-Sachs. The subsequent widespread adoption of Tay-Sachs carrier screening RESULTED IN A SIGNIFICANT DROP IN THIS DISEASE among the AJ population

Question 3

What diseases should be included when offering carriers screening to couples of AJ descent when pregnant or considering pregnancy?

Answer 3

• CF
• Canavan disease
• Familial dysautonomia
• Tay-Sachs
• Fanconi Anemia group C
• Niemann-Pick type A
• Bloom Syndrome
• Mucolipidosis IV
• Gaucher disease Type 1
  (carrier screening for these disorders should include testing for specific mutations which will result in a carrier detection rate of 95% or more)

Question 4

How is it determined what diseases to add to the recommended list for carrier screening?

Answer 4

• Natural history of disorder should be well understood and carry a potential for significant morbidity and/or mortality in the homozygous or compound heterozygous state
• Based on available literature there should be either >90% detection rate or an allele frequency of 1% or higher in the AJ population

Question 5

What should occur in the counseling of this carrier screening?

Answer 5

• General description of the disorders
• Variability of symptoms experienced
• Understanding that in the case of a negative test, a residual risk remains
• Carriers = not at risk of developing the disease, but can pass the gene to offspring
• The success of the Tay-Sachs screening program has resulted in the possible misperception that the Tay-Sachs gene is no longer present in the AJ community, but bc a carrier is asymptomatic, screening should occur in every generation
• Formal genetic counseling and medical genetics consultation should be readily available to anyone wanting it

Question 6

If only one partner in a couple is of AJ descent should testing be offered?

Answer 6

Yes, ideally the Jewish member of the couple should be tested first, and if positive, the other partner should be tested for that gene regardless of background