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Bloom Syndrome: BLM Recurrent Mutations

Alternate test name


Gene name / Alternate gene name
  • BLM
  • RECQL3, BS
Bloom syndrome, RecQ helicase-like
Lab area
Genome Diagnostics - Molecular Genetics
Method and equipment
Targeted analysis of recurrent mutations
Expected turn-around time
Prenatal: 2 weeks Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks
Specimen type

Blood; gDNA

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Specimen requirements
  • Blood: 5-10 mL in EDTA, 0.5 mL in EDTA (neonate);
  • DNA-minimum 10 ug in 100 uL low TE (pH8.0)
Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice.

Shipping information
The Hospital for Sick Children
Division of Genome Diagnostics
555 University Avenue, Black Wing, Room 3416
Toronto, ON
M5G 1X8
Phone: 416-813-7200 ext. 2
Hours: Monday to Friday, 8 a.m. to 4:30 p.m.
Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642
Email Molecular Lab:
Email Cytogenetics:
Background and clinical significance

Bloom syndrome (BLM) is characterized by short stature, sun-sensitive facial erythema, and immunodeficiency. Individuals with BLM are at increased risk for the development of cancer and diabetes. BLM is an autosomal recessive (AR) condition caused by the lack of RecQ DNA helicase, an enzyme involved in DNA repair. The BLM gene which codes for RecQ DNA helicase located at 15q26.1. One mutation in the BLM gene accounts for 98% of the mutations seen in Ashkenazi Jewish (AJ) individuals affected with BLM.

See related information sheet: Ashkenazi Jewish Screening Panel

Disease condition

Bloom Syndrome (part of the Ashkenazi Jewish screening panel)

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