Thalassemia intermedia in HbH-CS disease with compound heterozygosity for beta-thalassemia: challenges in hemoglobin analysis and clinical diagnosis

Tan, J. and Kok, J.L. and Tan, K.L. and Wee, Y.C. and George, E. (2009) Thalassemia intermedia in HbH-CS disease with compound heterozygosity for beta-thalassemia: challenges in hemoglobin analysis and clinical diagnosis. Genes & Genetic Systems, 84 (1). pp. 67-71. ISSN 1341-7568, DOI https://doi.org/10.1266/ggs.84.67.

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Abstract

Co-inheritance of alpha-thalassemia with homozygosity or compound heterozygosity for beta-thalassemia may ameliorate beta-thalassemia major. A wide range of clinical phenotypes is produced depending on the number of beta-thalassemia alleles (-alpha(alpha alpha--/alpha alpha, —/-alpha). The co-inheritance of beta-thalassemia with a-thalassemia with a single gene deletion (-alpha/alpha) is usually associated with thalassemia major. In contrast, the co-inheritance of beta-thalassemia with two alpha-genes deleted in cis or trans (--/alpha alpha or -alpha/-alpha) generally produces beta-thalassemia intermedia. In Southeast Asia, the most common defect responsible for alpha-thalassemia is the Southeast Asian (SEA) deletion of 20.5 kilobases. The presence of the SEA deletion with Hb Constant Spring (HbCS) produces HbH-CS disease. Co-inheritance of HbH-CS with compound heterozygosity for beta-thalassemia is very rare. This study presents a Malay patient with HbH-CS disorder and beta degrees/beta(+)-thalassemia. The SEA deletion was confirmed in the patient using a duplex-PCR. A Combine-Amplification Refractory Mutation System (C-ARMS) technique to simultaneously detect HbCS and Hb Quong Sze confirmed HbCS in the patient. Compound heterozygosity for CD41/42 and Poly A was confirmed using the ARMS. This is a unique case as the SEA a-gene deletion in cis (--(SEA)/alpha) is generally not present in the Malays, who more commonly posses the two a-gene deletion in trans In addition, the beta-globin gene mutation at CD41/42 is a common mutation in the Chinese and not in the Malays. The presence of both the SEA deletion and CD41/42 in the mother of the patient suggests the possible introduction of these two defects into the family by marriage with a Chinese.

Item Type: Article
Funders: UNSPECIFIED
Additional Information: Department of Molecular Medicine, Faculty of Medicine Building, University of Malaya, 50603 Kuala Lumpur, MALAYSIA
Uncontrolled Keywords: Thalassemia intermedia, Hb Constant Spring, CD41/42, Poly A, Amplification Refractory Mutation System, Duplex-PCR
Subjects: R Medicine
Divisions: Faculty of Medicine
Depositing User: Ms Haslinda Lahuddin
Date Deposited: 01 Oct 2012 03:43
Last Modified: 01 Oct 2012 03:43
URI: http://eprints.um.edu.my/id/eprint/3713

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