Table: Who Should Consider Genetic Screening?-Merck Manual Consumer Version

Who Should Consider Genetic Screening?

Group	Disorder*	Genetic Carrier Screening Tests
All	Cystic fibrosis	DNA analysis of a sample of blood or of cells from the inside of the cheek
Ashkenazi Jewish†	Canavan disease	DNA analysis of a sample of blood or of cells from the inside of the cheek
	Familial dysautonomia (hereditary dysfunction of the autonomic nervous system)	DNA analysis of a sample of blood or of cells from the inside of the cheek
	Tay-Sachs disease	Blood tests to measure the enzyme that is deficient in this disorder (hexosaminidase A) DNA analysis
African	Sickle cell anemia	Blood tests to check for abnormal hemoglobin
Cajun	Tay-Sachs disease	Blood tests to measure the enzyme that is deficient in this disorder (hexosaminidase A) DNA analysis
Mediterranean, Southeast Asian, Asian Indian, and Middle Eastern	Beta-thalassemia	Blood tests to measure the average size of red blood cells (mean corpuscular volume) If the average size is small, blood tests to check for abnormal hemoglobin DNA analysis
Southeast Asian, Cambodian, Chinese, Filipino, Laotian, and Vietnamese	Alpha-thalassemia	Blood tests to measure the average size of red blood cells If average size is small, blood tests to check for abnormal hemoglobin DNA analysis
* This list is not comprehensive. Screening for other disorders can be requested.
† Most (90%) Jewish people are Ashkenazi. Thus, Jewish people who do not know whether they are Ashkenazi should be screened. Some experts also recommend screening for other disorders, such as Gaucher disease, Niemann-Pick disease type A, and Fanconi anemia (syndrome) group C.

Group

Disorder*

Genetic Carrier Screening Tests

All

Cystic fibrosis

DNA analysis of a sample of blood or of cells from the inside of the cheek

Ashkenazi Jewish†

Canavan disease

DNA analysis of a sample of blood or of cells from the inside of the cheek

Familial dysautonomia (hereditary dysfunction of the autonomic nervous system)

DNA analysis of a sample of blood or of cells from the inside of the cheek

Tay-Sachs disease

Blood tests to measure the enzyme that is deficient in this disorder (hexosaminidase A)

DNA analysis

African

Sickle cell anemia

Blood tests to check for abnormal hemoglobin

Cajun

Tay-Sachs disease

Blood tests to measure the enzyme that is deficient in this disorder (hexosaminidase A)

DNA analysis

Mediterranean, Southeast Asian, Asian Indian, and Middle Eastern

Beta-thalassemia

Blood tests to measure the average size of red blood cells (mean corpuscular volume)

If the average size is small, blood tests to check for abnormal hemoglobin

DNA analysis

Southeast Asian, Cambodian, Chinese, Filipino, Laotian, and Vietnamese

Alpha-thalassemia

Blood tests to measure the average size of red blood cells

If average size is small, blood tests to check for abnormal hemoglobin

DNA analysis

* This list is not comprehensive. Screening for other disorders can be requested.

† Most (90%) Jewish people are Ashkenazi. Thus, Jewish people who do not know whether they are Ashkenazi should be screened. Some experts also recommend screening for other disorders, such as Gaucher disease, Niemann-Pick disease type A, and Fanconi anemia (syndrome) group C.