nrc

The genetic origin (s) and distribution of the sickle cell gene and the clinical description of the sickle cell disease in Sri Lanka.

NRC Grant:  16-001

Prof. Anuja P. Premawardhena
Department of Medicine
Faculty of Medicine
University of Kelaniya
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Area of Research:Clinical Medicine
Status:Ongoing

 

objectives

1) To identify the haplotype/different haplotypes of Sickle cell gene that cause Sickle cell disease in Sri Lanka and to conjecture the genetic background of the disease in Sri Lanka.

2) To describe the variation of clinical description between the haplotype/different haplotypes of Sickle cell gene that cause Sickle cell disease in Sri Lanka.

3) To screen the prevalence of sickle haemoglobin among the school children in randomly selected 5% of GramaNiladhari areas in Hambantota, Batticaloa, Puttalam, Kurunegala and Mannar Districts of Sri Lanka.

overview

Clinical presentations of Sickle cell disease in Sri Lanka, range from a crippling haemolyticanaemia, with severe exacerbations to a mild disorder often found merely by chance. This wide range of clinical presentation could be because of the different types of origins of Sickle Cell Disease. To determine the geographical origin of the disease genetic ancestral studies namely haplotype analysis could be carried out. These haplotype blocks are DNA segments that have been inherited intact over thousands of years. Therefore two unrelated individuals who share a common set of haplotype block share a common ancestor in the line of history.

To determine the geographical origin of the disease genetic ancestral studies namely haplotype analysis could be carried out. These haplotype blocks are DNA segments that have been inherited intact over thousands of years. Therefore two unrelated individuals who share a common set of haplotype block share a common ancestor in the line of history.

According to one theory the Sickle Cell gene may have arrived in Sri Lanka via Arab migrants to the island since 8th Century A.D. Arab migrations have been dated back to King Pandukabhaya reign and by about 8th Century A.D, the Arabs had formed colonies at the important ports of Sri Lanka, including Trincomalee, Jaffna, Colombo, Barbareen and Point de Galle. The origin of sickle cell gene in Sri Lanka might be related to these migrations. However, there are no scientific data to prove this conception. Rendering to the unpublished data most of the Sickle cell cases have been reported in districts where there were ancient ports. These districts include Hambantota, Batticaloa, Mannar and Puttalam. This is another inkling for the concept that the sickle cell disease entered the country via Arab migrators as history shows Arabs initially settled around those ancient ports. The different ethnic groups in Sri Lanka have a variable incidence of the Sickle haemoglobin (HbS). According to the previous studies the distribution Sickle cell disease and HbS was mainly confined to the southern part of the country with few cases being reported in the eastern province. The highest incidence of the HbS gene was reported in the Hambantota district which is located in the coastal area of eastern part of the southern province of Sri Lanka. This study will be done to determine the genetic origin (s) of Sickle cell gene, clinical description and its distribution in Sri Lanka. In order to determine the genetic origin (s) and clinical description of Sickle cell disease samples will be collected from known Sickle cell patients for haematological, biochemical and genetic studies. The distribution of the Sickle cell gene will be assessed via micro-mapping the prevalence of the disease among school children in Hambantota, Batticaloa, Puttalam, Mannar and Kurunegala districts. There is a correlation between the haplotype of the Sickle cell disease and its clinical description. Therefore the findings of this study will be helpful for better understanding of the disease, advancement of treatment, management and proper counselling of Sickle cell patients in Sri Lanka. Also, micro-mapping will help to decide the magnitude of Sickle cell disease prevalence in Hambantota, Batticaloa, Puttalam, Mannar and Kurunegala districts hence it provides adequate knowledge to initiate necessary health programmes on Sickle cell disease in respective areas