Beta Hemoglobin DNA Sequencing

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General Information

Lab Name
Beta Hemoglobin DNA Sequence
Lab Code
HBSEQ
Epic Ordering
Beta Hemoglobin DNA Sequence
Description

There are currently over 800 hemoglobin variants catalogued, of which approximately 500 are due to mutations in the beta-globin gene. In addition, approximately 95% of beta-thalassemia is caused by point mutations. This test, which sequences the coding regions and introns of the beta-globin gene (HBB) in both directions, identifies hemoglobin variants that are not easily diagnosed by electrophoresis/HPLC and can determine the cause of beta-thalassemia.

Indications for testing include:

  • Identification of hemoglobin variants detected by electrophoresis or HPLC
  • Differential diagnosis of microcytic anemia
  • Molecular characterization of beta-thalassemia mutations
  • Testing of a relative of an individual with a known beta-globin mutation
  • Prenatal diagnosis of potentially severe beta-thalassemia
  • Characterization of the sickle-cell mutation

Notes: To order testing for a relative of an individual with a known beta-globin mutation, see the Laboratory Medicine Online Test Guide for Beta Hemoglobin Sequencing, Relative [HBREL]

References
  • Origa R. Beta-Thalassemia. GeneReviews: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A, editors. 2000 Sep 28 [updated 2018 Jan 25]. 20301599
  • Old JM. Screening and genetic diagnosis of haemoglobin disorders. Blood Rev 2003, 17:43-53. 12490210
  • Globin Gene Server: http://globin.cse.psu.edu/
Forms & Requisitions

Genetics Requisition

Synonyms
Globin, HBB, Hemoglobin C, Hemoglobin S, Hemoglobinopathy, Sickle Cell, Thalassemia intermedia, Thalassemia major
Components

Interpretation

Method

DNA sequencing of the coding regions, introns, and flanking sequences of the hemoglobin beta (HBB) gene in both directions to detect point mutations causing beta globin variants and beta thalassemia.

This test sequences bidirectionally a 2 kb contiguous region of the HBB (beta globin) gene from approximately bases 61941 to 63927 of Genbank U01317, corresponding to bases minus 195 to plus 1792 relative to the start of transcription. Patient sequences are compared against Genbank U01317 as genomic reference sequence to detect mutations. Mutations are reported at the genomic level, with base 1 corresponding to the start of transcription. Mutations that change an amino acid are reported at the protein level according to the sequence of the mature protein without its initiator methionine, and may also be described by the traditional name of the hemoglobin variant.

Correspondence between this mutation nomenclature system and the HGVS nomenclature system may be found at the web site http://globin.cse.psu.edu.

This test was developed and its performance characteristics determined by the Department of Laboratory Medicine at the University of Washington.

Reference Range
See individual components
Ref. Range Notes

No mutation detected.

References
  • Origa R. Beta-Thalassemia. GeneReviews: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A, editors. 2000 Sep 28 [updated 2018 Jan 25]. 20301599
  • Old JM. Screening and genetic diagnosis of haemoglobin disorders. Blood Rev 2003, 17:43-53. 12490210
  • Globin Gene Server: http://globin.cse.psu.edu/
Guidelines

Ordering & Collection

Specimen Type
Blood, amniocytes, chorionic villus tissue or cultured cells.
Collection

BLOOD:

  • Adult: 5 mL LAVENDER TOP tube
  • Child: 2 mL LAVENDER TOP tube
  • Also acceptable: YELLOW TOP (ACD) tube
  • Unacceptable: Heparin green top tubes

AMNIOCYTES or CULTURED CHORIONIC VILLUS CELLS:

  • Two (2) T23 or One (1) T75 flask (minimum 1-T25 flask)

CHORIONIC VILLIS and/or TISSUE:

  • In sterile tube or culture media, at least 5 mg tissue.

Prenatal testing requires concomitant testing for maternal cell contamination (see Online Test Guide, Lab Mnemonic Maternal Cell Contamination [MCC] for ordering and specimen requirements)

Forms & Requisitions

Genetics Requisition

Handling Instructions

Blood: Refrigerate whole blood up to 1 week.

Amniocytes & cultured CVS cells: hold flasks at room temperature.

Chorionic villi &/or tissue: hold at room temperature.

Outside Laboratories: Ship whole blood at ambient temperature for receipt within 1 week of specimen collection.- For cultured amniocytes or chorionic villus cells and for CVS or other tissue, transport and store at room temperature within 24 hours of obtaining CV or removing cultured cells from incubator.

Quantity
requested: Entire specimen
minimum: Blood: 1 mL. Amniocytes, cultured chorionic villus cells, chorionic villi or tissue: as above.

Processing

Processing

Please notify genetics about amniocytes, cultured chorionic villus cells, chorionic villi or tissue.

Performance

LIS Dept Code
Genetics (GEN)
Performing Location(s)
UW-MT Genetics

Attention: Genetics Lab
Clinical lab, Room NW220
University of Washington Medical Center
1959 NE Pacific Street
Seattle, WA 98195

Tel: 206-598–6429 M–F (7:30 AM–4:00 PM)
Fax: 206-598–0304
Lab email: genelab@uw.edu

Tel (EXOME only): 206-543-0459

Manager

Rebecca Gaulin, rgaulin@uw.edu

Genetic Counselors

Angela Jacobson, MS, LGC agibson@uw.edu
Sarah Paolucci, MA, MS, LGC, spaolucc@uw.edu
Jenna Huey, MS, LGC, jlhuey@uw.edu
Sandra Coe, MS,LGC, scoe20@uw.edu
Dru Leistritz, MS, LGC, dru2@uw.edu (EXOME testing only)

Variant Review Scientist

Ankita Jhuraney, PhD

Faculty

Colin C. Pritchard, MD, PhD
Brian H. Shirts, MD, PhD
Christina Lockwood, PhD, DABCC
Stephen Salipante, MD, PhD
Eric Konnick, MD, MS
Niklas Krumm, MD,PhD
Vera Paulson, MD, PhD
Jillian Buchan, PhD, FACMG

Frequency
Performed weekly. Results within 3 weeks.
Available STAT?
No

Billing & Coding

CPT codes
81364
Billing Comments

For pricing information, contact Client Support Services 206-520-4600 or 800-713-5198.

LOINC
21689-5