Co-inheritance of compound heterozygous Hb Constant Spring and a single –α3.7 gene deletion with heterozygous δβ thalassaemia: A diagnostic challenge
- Author:
Raja Zahratul Azma
;
Ainoon Othman
;
Norazlina Azman
;
Hafiza Alauddin
;
Azlin Ithnin
;
Nurasyikin Yusof
;
Noor Farisah Razak
;
Nor Hidayati Sardi
;
Noor Hamidah Hussin
- Publication Type:Case Reports
- Keywords:
Hb Constant Spring, α+ thalassaemia, δβ thalassaemia, capillary electrophoresis, molecular analysis
- From:The Malaysian Journal of Pathology
2012;34(1):57-62
- CountryMalaysia
- Language:English
-
Abstract:
Haemoglobin Constant Spring (Hb CS) mutation and single gene deletions are common underlying
genetic abnormalities for alpha thalassaemias. Co-inheritance of deletional and non-deletional alpha
(α) thalassaemias may result in various thalassaemia syndromes. Concomitant co-inheritance with
beta (β) and delta (δ) gene abnormalities would result in improved clinical phenotype. We report here
a 33-year-old male patient who was admitted with dengue haemorrhagic fever, with a background
history of Grave’s disease, incidentally noted to have mild hypochromic microcytic red cell indices.
Physical examination revealed no thalassaemic features or hepatosplenomegaly. His full blood
picture showed hypochromic microcytic red cells with normal haemoglobin (Hb) level. Quantitation
of Hb using high performance liquid chromatography (HPLC) and capillary electrophoresis (CE)
revealed raised Hb F, normal Hb A2 and Hb A levels. There was also small peak of Hb CS noted in
CE. H inclusions was negative. Kleihauer test was positive with heterocellular distribution of Hb
F among the red cells. DNA analysis for α globin gene mutations showed a single -α-3.7 deletion
and Hb CS mutation. These fi ndings were suggestive of compound heterozygosity of Hb CS and
a single -α-3.7 deletion with a concomitant heterozygous δβ thalassaemia. Co-inheritance of Hb
CS and a single -α-3.7 deletion is expected to result at the very least in a clinical phenotype similar
to that of two alpha genes deletion. However we demonstrate here a phenotypic modifi cation of α
thalassemia presumptively as a result of co-inheritance with δβ chain abnormality as suggested by
the high Hb F level.
- Full text:W020151218427936530032.pdf
