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The American College of Obstetricians and Gynecologists recommends that carrier screening for Tay–Sachs disease, Canavan disease, familial dysautonomia, and cystic fibrosis be offered to those of Ashkenazi Jewish ancestry, while the ACMG recommends screening for a panel of nine genetic conditions (see Table 10.1). Expanded screening panels that cover these conditions as well as a broader range of conditions more commonly carried by the Ashkenazi Jewish population are also available. Tay–Sachs screening is also recommended for individuals of French Canadian, Cajun, and Amish backgrounds or those with a family history.

For a couple where one partner is Ashkenazi Jewish, the person of Ashkenazi Jewish background should be tested first. Counseling regarding residual risk should be performed, particularly whenever screening an individual without Ashkenazi Jewish ancestry, due to the potential to be a carrier of a rare mutation.

In the case of screening for Tay–Sachs disease, DNA‐based mutation analysis is highly effective for those in high‐risk populations. However, the serum or leukocyte hexosaminidase enzymatic activity (the enzyme that is deficient in those affected by Tay–Sachs disease) can be used to distinguish carriers from noncarriers in a manner that is not specific to ethnic background. Because it is not mutation specific, biochemical analysis is more sensitive and therefore preferred for screening for Tay–Sachs disease among individuals of nonhigh‐risk ancestry.

Table 10.1 Recommended carrier screening for individuals of Ashkenazi Jewish backgrounds

American College of Obstetricians and Gynecologists	American College of Medical Genetics and Genomics
Cystic fibrosis	Cystic fibrosis
Tay–Sachs disease	Tay–Sachs disease
Familial dysautonomia	Familial dysautonomia
Canavan disease	Canavan disease
	Fanconi anemia (group C)
	Niemann–Pick disease (type A)
	Bloom syndrome
	Mucolipidosis IV
	Gaucher disease