Medical Genetics

Bloom Syndrome Carrier Testing

Bloom syndrome is characterized by severe growth retardation and a predisposition to infections and malignancies which result in reduced life expectancy. The syndrome is an autosomal recessive disorder which is caused by mutations in the BLM gene. The carrier risk for Bloom syndrome in the Ashkenazi Jewish population is 1 in 100.

Bloom syndrome carrier testing by DNA analysis is offered as part of a genetic screening panel for the Ashkenazi Jewish population which also includes mucolipidosis IV, Niemann-Pick disease type A, and glycogen storage disease type 1A. See Ashkenazi Jewish Genetic Screening - Panel 2 for testing information.

Indications for Testing

Carrier screening
Gamete donors

Testing Methodology

Direct mutation analysis: Our laboratory utilizes Amplification Refractory Mutation System (ARMS) technology to screen for a single mutation relevant to the Ashkenazi Jewish population. The mutation is 2281del6/ins7.

Sensitivity

The carrier detection rate for DNA analysis of Bloom syndrome in the Ashkenazi Jewish population is 97%.

This carrier screening test is most appropriate for individuals of Ashkenazi Jewish descent. This test may not be appropriate for individuals from other ethnic backgrounds. The sensitivity of this carrier screen in non-Jewish populations has not been established. This test is not appropriate for fetal diagnosis or diagnosis of individuals with clinical phenotype.

Specimen Requirements

Blood: 5 cc whole blood collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. Do not centrifuge or freeze. Sample may be refrigerated or stored at room temperature.