Tests and Indications
Cystic Fibrosis
Cystic fibrosis is the most common genetic disorder among Caucasians
(1:29) and is less common among other ethnic groups (see table
below). The American College of Medical Genetics (ACMG) recommends
that CF screening be offered to couples considering starting a
family and recommends the mutation panel listed below for all ethnicities.
The detection rate differs with ethnic origin and is shown along
with after testing residual risk estimates in the table below.
Mutations Analyzed:
| deltaF508 | deltaI507 | G542X | G551D | W1282X |
| N1303K | R553X | 621+1G->T | R117H | 1717-1G->A |
| A455E | R560T | R1162X | G85E | R334W |
| R347P | 711+1G->T | 1898+1G->A | 2184delA | 1078delT |
| 3849+10kbC->T | 2789+5G->A | 3659delC | I148T | 3120+1G->A |
This test distinguishes the F508C, I507V, and I506V polymorphisms and the poly T allele is reported where clinically significant.
Sensitivity and Estimated Carrier Risk:
| Estimated Carrier Risk | |||
| Ethnic Group | Detection Rate | Before Test | After Test |
| Ashkenazi Jewish | 97% | 1/29 | ~1 in 930 |
| European Caucasian | 80% | 1/29 | ~1 in 140 |
| African American | 69% | 1/65 | ~1 in 207 |
| Hispanic American | 57% | 1/46 | ~1 in 105 |
| Asian American | ND | 1/90 | ND |
Ashkenazi Jewish Genetic Disease Screening
A video entitled: "The Importance of Genetic Screening for Ashkenazi
Jewish People" is available on our website and may be shared with
your patients.
See the video: Genetic
Screening Video (real
player needed)
The Molecular Genetics Laboratory currently provides direct mutation
detection for ten inherited diseases common in the Ashkenazi Jewish
population. The diseases and the mutations screened are listed
in the table below. These tests may be used for both carrier screening
and diagnosis of symptomatic individuals. For couples of
mixed ethnicity it is recommended that the Jewish partner be tested
first. Contact the laboratory to determine appropriate testing
procedures for individuals of mixed heritage.
Disease |
Mutations Detected |
Sensitivity in Ashkenazi
Jews |
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| Bloom Syndrome | blm-ASH (6 bp deletion and 7 bp insertion at nucleotide 2281 of the BLM gene) | 99% |
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| Canavan Disease | Y231X | E285A | 98% |
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| Gaucher Disease | R496H | N370S | 84GG | IVS2+1 | L444P | 99% |
Glycogen Storage Disease,1A |
R83C | 98% |
||||
Fanconi Anemia, Type C* |
IVS4+ 4A>T | 98% |
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| Familial dysautonomia | 2507+ 6T>C | 99% |
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| Familial Hyperinsulinism | IVS32- 9>A | delta F1388 | 88% |
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| Maple Syrup Urine Disease | R183P | 90% |
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| Mucolipidosis, Type 4 | IVS3- 2A>3 | 511de l6434 | 94% |
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| Tay-Sachs Disease | 1277ins TATC | 1421+ 1G>C |
G269S | 98% |
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* Fanconi Anemia is a complex disease caused by at least 11 different
genes. Among Ashkenazi Jews, a single founder mutation in the
FANCC gene is responsible for 98% of cases of Fanconi Anemia
in this population. For non-Jewish individuals, chromosomal breakage
studies should be considered. This type of testing is available
in the laboratory of Dr
Arleen Auerbach at Rockefeller University.
