Icahn School of Medicine at Mount Sinai
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Genetic Testing Lab

Test Catalog Molecular Genetics Laboratory Bloom Syndrome

Bloom Syndrome

Test Description:
Bloom syndrome (BS) is an autosomal recessive disorder characterized clinically by proportionate pre- and postnatal growth deficiency, sun-sensitive, telangiectatic, hypo- and hyperpigmented skin, predisposition to malignancy, and chromosomal instability. BS is more prevalent in the Ashkenazi Jewish population with a carrier frequency of approximately 1 in 134. The most common mutation in this population, termed Blm Ash, is a 6 bp deletion and 7 bp insertion in the BLM gene (c.2207_2212delATCTGAinsTAGATTC (2281del6/ins7)). Testing for this mutation identifies approximately 99% of Ashkenazi Jewish carriers of BS. The American College of Medical Genetics recommends that carrier screening for BS be offered to individuals with at least one grandparent of Eastern European (Ashkenazi) Jewish ancestry before/during pregnancy.

Full gene sequencing is available for reproductive partners of known mutation carriers. Prenatal diagnosis is also available. Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss. 

1. Ellis, N.A. et. al. The Bloom’s syndrome gene product is homologous to RecQ helicases. Cell 83:655-666, 1995.
2. Scott, S.A., Edelmann, L., Liu, L., Luo, M., Desnick, R.J. and Kornreich, R. Experience with carrier screening and prenatal diagnosis for sixteen Ashkenazi Jewish Genetic Diseases. Hum. Mutat. 31:1-11, 2010.

Specimen Requirements:


Two 5-10 ml tubes of anticoagulated blood. The preferred anticoagulant is EDTA (lavendar top tubes) or two 5-10 mL tubes of anticoagulated blood in ACD (yellow top).


  • Chorionic Villi: 5-10 mg in conical tube with sterile saline OR transport media
  • Amniotic Fluid: 10ml in conical tube
  • Cultured Cells: two confluent T-25 flasks

Additionally, please send:

  • 5-10ml maternal blood in EDTA (lavender top) required to perform MCC studies on all prenatal samples and in case maternal confirmation studies are necessary 
  • 5-10ml paternal blood in EDTA (lavender top)  in case paternal confirmation studies are necessary

Shipping: Send at room temperature.

Turnaround Time: 10-14 days

CPT Codes: 83891, 83892x2, 83898, 83912, 83914

Consent and Requisition Forms: Carrier Screening Requisition and Consent [PDF]

Additional Information: Expanded Ashkenazi Jewish Carrier Screening Brochure [PDF]

Related Tests: Ashkenazi Jewish Carrier Test Panel

Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.