HEMOGLOBIN, 23(3), 291-293 (1999)

SHORT COMMUNICATION

Hb Khartoum [ p124(H2)Pro+Arg] in a Vietnamese Female

J.G. Hendy, K. Garofalo, and D.K. Bowden

Clinical Genetics Laboratoty, Monash Medical Centre Clayton, 31 68, Australia

Hb Khartoum [p 124(H2)Pro+Arg] was first identified during screening for hemo- globinopathies in Khartoum (1). The abnormal hemoglobin (Hb), which comprised approxi- mately 30% of the total Hb, had an electrophoretic mobility similar to Hb S. Although theoretically the replacement of proline by arginine might be expected to produce significant alteration in the configuration of the P-globin chain, there was no laboratory evidence of Hb instability.

During routine screening of antenatal patients we recently observed, in a 28-year-old pregnant Vietnamese woman, an abnormal Hb which eluted at a position similar to Hb D on cation exchange high performance liquid chromatography (HPLC) (VariantTM Analyzer p- Thalassemia Short Program; Bio-Rad Laboratories, Hercules, CA, USA). This Hb variant, which comprised 36.8% of the total Hb, migrated slightly anodal to Hb S on cellulose acetate electrophoresis at alkaline pH, whilst on capillary electrophoresis (2) it migrated slightly anodal to Hb A (migration time 15.67 minutes cf16.16 minutes). All hematological values were within the normal range: Hbl3lg/L, RBC 4.76 x 10l2/L, MCV 80.5 E, RDW 14.4, Hb A, 1.9%, and Hb F <0.9%. DNA was extracted from 10 mL EDTA anticoagulated whole blood using the Progenome 11 DNA Extraction Kit (Progen Industries Limited, Darra, Queensland, Australia) and the presence of the common a-thalassemia (thal) deletions, -a3 7,

Correspondence should be addressed to: tory Level 3, Monash Medical Centre, 246 Clayton Road, Clayton, 3 168, Australia; TEL: +613-9594-3398; FAX: +613-9594-3502; e-mail: jeanhendy@hotmail.com

Mrs. Jean G. Hendy, Clinical Genetics Labora-

29 1

Copyright 0 1999 by Marcel Dekker. Inc. www.dekker.com

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292 HENDY, GAROFALO, AND BOWDEN

Figure 1. Part ofa sequencing gel showing the C+G mutation in codon 124 of the f3-globin gene, resulting in the substitution of the amino acid (aa) proline (Pro) by arginine (Arg).

a4.2 - , and - -SEA, excluded by Southern Blot analysis using standard procedures (3). Se- quencing of the P-globin gene was performed using the Thermo Sequenase Radio-labelled Terminator Cycle Sequencing Kit (Amersham Life Science, Inc., Cleveland, OH, USA). This revealed a C+G mutation in codon 124 (Fig. 1) resulting in the replacement of proline by arginine and identified the variant as Hb Khartoum. To our knowledge this is the first report of Hb Khartoum in a Vietnamese patient, and is thixefore likely to be an independent mutation.

Acknowledgments. The authors thank Mr. Louis Meyepa, Department of Haematol- ogy, Monash Medical Centre, Clayton, Australia, for performing the HPLC analysis, Ms. Margaret Jenkins and Mr. Ian Smith, Department of Haematology, Austin and Repatriation Medical Centre, Heidelberg, Australia, for performing the capillary electrophoresis, and Ms. Pola Better, Department of Haematology, Mercy Hospital for Women, East Melbourne, Australia, for sending this sample.

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Hb KHARTOUM IN VIETNAMESE FEMALE 293

REFERENCES

1.

2 .

Clegg, J.B., Weatherall, D.J., Wong Hock Boon, and Mustafa, D.: Two new haemoglobin variants involving proline substitutions. Nature, 22:379-380, 1969. Jenkins, M.A., Hendy, J., and Smith, I.L.: Evaluation of Hemoglobin A, quantitation assay and hemoglobin variant screening by capillary electrophoresis. J. Cap. Elec., 4: 137-143, 1997. Old, J.M. and Higgs, D.R.: Gene analysis. In: The Thulussuemius, edited by D.J. Weath- erall, Vol. 6, pages 74-1 02, Methods in Hematology, Churchill Livingstone, Edinburgh, Scotland, 1983.

3 .

Received: January 20,1999. Accepted: March 29,1999.

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