single sickle-cell allele (trait) confers a selective advantage in other words, being a heterozygote is advantageous. Specifically, humans with one of the two alleles of sickle-cell disease show less severe symptoms when infected with malaria. (Wellems et al., 2009) 5 1.2.1.3.2. Western Sudan: The presence of HbS is already well documented among Kordofan and Darfur region inhabitants, especially Albaggara, an Afro-Arab constellation of tribes with a predominantly African descent (Adams, 2009). Some findings of a study conducted in Elobied hospital in North Kordofan State, showed that sickle cell trait in relatives of patients suffering from sickle cell disease (SCD) who were referred to this Hospital, was 54% of target samples, which concentrated mainly in two tribes, Bederia and Fulani. Sickle cell disease in Messeryia of Darfur and Messeryia Hummer of Kordofan showed a prevalence of 30.4% and 18% respectively. It is estimated that one in every 123 children born in Messeryia tribe is at risk of having SCD (Balgir, 2012). Many indigenous tribes that inhabit Darfur region and belong to the Negroid ethnic group and are a part of Nilo-Saharan language family such as the Berge, Fur and Masaleet had the highest frequencies of the S gene among them (Paul et al., 2011). 1.2.2. The symptoms of sickle cell anaemia: The following is symptoms and complications associated with sickle cell anaemia. Each child may experience symptoms differently. Symptoms and complications may include, but are not limited to, the following: The most common symptom of anemia is fatigue (feeling tired or weak). Other signs and symptoms of anemia may include: Shortness of breath, Dizziness, Headaches, Coldness in the hands and feet, Paler than normal skin or mucous membranes (the tissue that lines the nose, mouth, and other organs and body cavities) and Jaundice (Platt et al., 1994). . 6 1.2.2.1. Acute anemia Defined as a decline in hemoglobin concentration by 2.0 g/dL or more below the patient’s baseline value, may have diverse etiologies. Therefore, splenic sequestration in a child or an aplastic episode at any age may require urgent evaluation and therapy. The reticulocyte count is an important index to assess diminished red blood cell production (low reticulocyte count, as can occur in parvovirus infected individuals, results in aplastic crisis, accelerated hemolysis, or sequestration in the lungs, spleen, or liver. An aplastic crisis is a common feature of SCD, especially in childhood. (Smith et al., 2004). 1.2.2.2. Pain in sickle cell disease Recurrent episodes of acute, severe pain are the hallmark of SCD. The pain is highly variable both within and among patients, and is the result of complex and poorly understood interactions between biological and psychosocial factors. Vasoocclusion within the bone marrow vasculature leads to bone infarction, which in turn results in the release of inflammatory mediators that activate afferent nerve fibers and cause pain. Although the basic mechanism is simple, the precise details of the vaso-occlusion are poorly understood, involving complex interactions between red cells, endothelium, white cells and platelets. The unpredictability of the pain is a major factor in undermining the patient's ability to cope (Ballas, 2005). Acute pain frequently occurs spontaneously, but may be precipitated by infections, skin cooling, dehydration or stress. Acute pain in SCD is described as throbbing, sharp or gnawing, and patients can usually recognize whether it is typical of their SCD. If the patient thinks the pain is atypical, then other causes of pain should be sought. Acute painful episodes may occur on top of chronic pain, or be precipitated by other painful events, such as cholecystitis. Hospital admissions for acute pain in SCD typically last 4–10 days, but this varies widely. If persist more than 3 months it’s considered 7 as chronic, chronic pain may be an extension of recurrent acute painful episodes or in a specific tissue or organ, such as avascular necrosis of the hips, or leg ulcers. Chronic pain is often associated with other conditions that enhance its chronicity. These include psychosocial factors such as depression, anxiety, feelings of despair, insomnia, loneliness, helplessness and dependence on pain medications, chronic pain can be hard and may lead in mental draining. (Serjeant, 2001). 1.2.3. Complications of Sickle Cell Disease 1.2.3.1. Sickle cell crisis The term "sickle cell crisis" is used to describe several independent acute conditions occurring in patients with sickle cell disease, the most common complication of SCD is an acute episode ofsevere pain referred to as an acute vaso-occlusive crisis (VOC). AVOC is defined as pain resulting from tissue ischemia caused by vaso-occlusion most commonly in the bone(s) and bone marrow (Platt et al., 1994). 1.2.3.2. Vaso-occlusive crisis (VOC) A VOC is the hallmark acute complication for SCD and manifests as acute severe pain. The sickled erythrocytes block the flow of blood through the small blood vessels (capillaries) resulting in ischemia. Sudden episodes of pain throughout the body are a common symptom of SCD. This sudden pain can range from mild to very severe form and usually lasts from hours to a few days. VOCs and their accompanying pain most commonly occur in the extremities, chest, and back. When they occur in other sites, they can be confused with, or can be the prodromal stage