Abstract
In the last five decades, genetic structure of populations are being studied in via ABO blood groups system, mtDNA and Y chromosome makers to understand history of human migration and relatedness of ethnic groups settled in close proximity. In the present study, the distribution of ABO and Rh blood groups and associated traits among various ethnic groups in Kogi State was analysed to determine the genetic composition of various ethnic groups. The study was carried out using students of Kogi State College of Nursing and Midwifery, Obangede. Participants for the study included 1,863 students of the college (1,427 females and 436 males) aged 16-40 years. The study is both retrospective and prospective. Records of admitted students into the college spanning 11 years (2002–2013) consecutively were retrospectively and prospectively collected from the various record units of the College. ABO, Rh blood group and Hb-electrophoresis tests were carried out on a white porcelain tile using
CHAPTER ONE
GENERAL INTRODUCTION 1.1 Background of Study Blood is defined as ―the red viscous fluid that circulates round the body supplying O2 and nutritive substances absorbed from the gastrointestinal tract to the tissues, returns CO2 to the lungs and other products of metabolism to the kidneys, functions in the regulation of body temperature, and distributes hormones and other agents that regulate cell function‖ (Saladin, 2003; Barrett et al., 2010). Blood has always had a special mystique. From time immemorial, people have seen blood flow in the body and with it, the life of individual depends. People thus presumed that blood carried a mysterious ―vital force,‖ and Roman gladiators drank it to fortify themselves for battle. From ancient Egypt to nineteenth-century America, physicians drained ―bad blood‖ from their patients to treat everything from gout to headaches, from menstrual cramps to mental illness (Saladin, 2003). ―Blood group‖ can be defined as inherited allogeneic variation detected on the surface of blood cells (Daniels, 2002). The term applies to a defined system of red blood cell antigens (blood group substances) controlled by a genetic locus having a variable number of alleles e.g. A, B, and O in the ABO system (Murray et al., 2003; Daniels, 2002). The blood group is determined by the genetic make-up of the alleles of a system (Bakare et al., 2006; Bhuvnesh et al., 2011).
There are at least other 29 known blood groups with a total of more than 240 antigens, including the MN, Duffy, Kell, Kidd, and Lewis groups (Storry and Olsson, 2004). These rarely cause transfusion reactions. The Kell, Kidd, and Duffy groups occasionally cause Haemolytic Disease of the Newborn (Iyiola et al., 2011).The most famous blood groups are those of ABO and Rhesus (Rh) series (Khan et al., 2009). The ABO blood group are the first red cell antigens while the Rhesus blood group are the most immunogenic red cell antigens discovered (Chima et al., 2012). Both are routinely typed for in any blood bank or blood transfusion service (Bakare et al., 2006; Enosolease and Bazuaye, 2008). Blood-group antigens may be carbohydrate structures on red cell surface glycoproteins or glycolipids (Storry and Olsson, 2004; Akinnuga, 2011), or they may be determined primarily by the amino acid sequence of polypeptides or glycoproteins (Suzuki, 2005). At least 23 red cell surface proteins express blood-group polymorphism (Daniels, 2002; Yamamoto et al., 2012).
The ABO blood group system of carbohydrate antigen expression on the surface of human red blood cells (RBCs) was first described by Karl Landsteiner in 1900 and represented an important step towards development of safer blood transfusions (Owen, 2000; Loscertales et. al., 2007; Iyiola et al., 2011; Chandra and Gupta, 2012). Alfred von Decastello and Adriano Sturli discovered the 4th type, AB, in 1902 (Eweidah et al., 2011) while Landsteiner and Weiner in 1940 discovered the Rhesus (Rh) blood group (Iyiola et al., 2011).
Based on RBC agglutination patterns, individuals could be divided into 4 major groups A, B, AB, and O (Saladin, 2003; Suzuki, 2005; Yamamoto et al., 2012). ABO and Rhesus (Rh) blood group antigens are hereditary characters and are useful in population genetic studies, researching population migration patterns, as well as resolving certain medico-legal issues, particularly of disputed paternity and more importantly in compatibility test in blood transfusion practice (Enosolease and Bazuaye, 2008; Reddy and Sudha, 2009; Yamamoto et al., 2012). ABO and Rh genes and phenotypes vary widely across ethnic groups, races and geographical boundaries despite the fact that the antigens involved are stable throughout life (Bhuvnesh et al; 2011; Iyiola et al., 2011; Chandra and Gupta, 2012). ABO gene is located on the long arm of the ninth human chromosome (9q34.1) while the Rh D and RHce genes encoding the Rh proteins (d and cc/ee, respectively) are located on chromosome 1p34-p36 (Rai et al., 2009; Iyiola et al., 2011). The ABO blood group gene is known to code for a glycosyltransferase, which acts at the last step of sequential extension of oligosaccharide chains attached to glycoproteins or glycolipids (Suzuki, 2005). The Rh blood group is named for the rhesus monkey, in which the Rh antigens were discovered in 1940. It is the most complex of the human blood-group systems with 52 well-defined antigens, the most immunogenic of which is D (RHD) (Daniels, 2002; Saladin, 2003). The Rh blood groups rank with ABO groups in clinical importance because of their relation to haemolytic disease of the newborn (HDN) and their importance in blood transfusion (Adeyemo and Soboyejo, 2006; Bakare et al., 2006). The Rh is genetically complex but it is simply described in terms of a single pair of alleles, D and d This group is determined by three genes called C, D, and E, each of which has two alleles: C, c, D, d, E, e. The Rh blood type is tested by using an anti-D reagent (Daniels, 2002; Saladin, 2003).
Rh frequencies vary among ethnic groups just as ABO frequencies. Between 82% and 88% of Caucasians, about 95% of black Africans, and almost 100% of people from the Far East are D-positive (Iyawe et al., 1999; Daniels, 2002). The first discovery that the frequencies of the blood groups differed from one population to another was made in the early 20th century. Subsequent results from practically all countries of the world have corroborated this, and have also shown that frequency figures are valid only for the specific population from which they are derived (Mourant et al., 1976). In contrast to the ABO group, anti-D antibodies are not normally present in the blood. They form only in Rh- individuals who are exposed to Rh+ blood (Saladin, 2003).The antigens of the Rh system are encoded by two genes, RHD and RHCE. They are highly homologous and have very similar genomic organization, each containing 10 coding exons arranged in opposite orientation on chromosome 1 (Daniels, 2002). 1.2 Statement of Problem In the last five decades, numerous studies have been carried out on the genetic composition of various population groups around the world including some parts of Nigeria. However, genetic studies among the ethnic groups of Kogi State are non-existent. Hence, the need for the present study to determine the frequencies of ABO and Rhesus blood groups among the ethnic groups of Kogi State. The present study attempts to provide initial data of genetic composition of ethnic groups in Kogi State, using ABO blood group system. 1.3 Justification/Significance of Study
The main purpose of the study is to establish the distribution of ABO and Rh blood groups among the various ethnic groups in Kogi State with a view to providing useful data for the government and health care providers in tackling health-related problems. The present study will help to correlate the ethno-historical, mythological and other related records in association with genetic data that can be useful in demonstrating the origin of a population and the genetic relationship between populations. The knowledge of the frequencies of ABO and Rh blood groups at local and regional levels are helpful in the effective management of blood banks and in blood transfusion services. Data from this study will be of immense use to the geneticists, biologists, blood transfusion services, policy makers and clinicians. To create awareness for the Primary Health Care (PHC) Centres on the frequency distribution pattern of ABO and Rhesus (RHD) blood groups and associated traits in people of Kogi State. The findings will add to the existing literature on gene frequencies of ABO and Rh blood groups in the Nigerian populations. 1.4 Aims and Objectives of the Study 1.4.1 The aim of the study This study aims to investigate the genetic structure and variation of population in Kogi State, Nigeria, with respect to ABO blood group and Rhesus factor. 1.4.2 Objectives of the study The objectives of the study are to:
i. describe the genetic structure of Kogi State indigenes with respect to ABO and Rh blood groups.
ii. describe the pattern of distribution of ABO and Rh blood groups among the ethnic groups of Kogi State.
iii. investigate any association between blood groups and some disease and physiological traits.
iv. provide baseline data on ABO and Rh blood groups for scientists, health professionals, health-care providers and policy makers in Kogi State
1.5 Research Hypothesis
i. There is variation in the distribution of ABO and RH (D) blood groups among different ethnic groups in Kogi State.
ii. There is association between blood group and some physical and physiological traits.