Sickle Cell Disease.
One of the most relevant hematological emergencies.
What is Sickle Cell Disease (SCD)
Sickle Cell Disease (SCD) is a group of inherited red blood cells disorders. People suffering from SCD have an abnormal protein in their red blood cells.
SCD is among the world’s most common serious inherited diseases with more than 300,000 annual births, 85% are born in sub-Saharan Africa. SCD accounts for 8-16% of all-cause mortality in childhood in Sub-Saharan Africa even though it represents 2% or less of all births in the region. Increasing migration from high prevalence areas of Africa to European countries has grown their SCD population. The outcome of SCD in low-middle income countries is grim: less than 50% of affected births will survive beyond the 10th birthday. Outcomes in high income countries have been greatly improved by multiple factors including early diagnosis by newborn screening (NBS), prophylactic penicillin and comprehensive follow up. The optimal care for patients with SCD in Africa should incorporate this approach plus laboratory capacity and blood banking services.
DISEASE INCIDENCE
Sickle cell disease (SCD) is among the world’s most common serious inherited diseases with more than 300,000 annual births, 85% are born in sub-Saharan Africa.
GEOGRAPHICAL DISTRIBUTION
The prevalence of the disease is high throughout large areas in sub-Saharan Africa, the Mediterranean basin, the Middle East, and India. Most of the babies born with SCD live in three countries: Nigeria, the Democratic Republic of the Congo, and India.
SURVIVAL
Its developing depends on the level of care and health organization. The outcome of SCD in low-middle income countries is grim: less than 50% of affected births will survive beyond the 10th birthday.
INHERITANCE PATTERN
When two people who are carriers of an autosomal recessive condition have a child, there is a 25% (1 in 4) chance that the child will have the condition, a 50% (1 in 2) chance that the child will be a carrier like each of the parents, and a 25% (1 in 4) chance that the child will not have the condition and not be a carrier.
ORGAN COMPLICATIONS
The most common organ-related complications that characterize sickle cell disease as a severe clinical entity include vaso-occlusive or pain crisis, acute chest syndrome, stroke, and priapism.
LIFE EXPECTANCY
Among children and adults with sickle cell anemia (homozygous for sickle hemoglobin), the median age at death was 42 years for males and 48 years for females. Among those with sickle cell-hemoglobin C disease, the median age at death was 60 years for males and 68 years for females.
DIAGNOSIS
This include medical history, symptoms, physical exam, and laboratory test results etc.
Blood test, screening for hemoglobin S, is part of routine newborn screening in several countries.
NEWBORN SCREENING
The first countries to introduce sickle cell screening on a national scale were France and England. More than 8 million babies have been screened in England; 3686 screen positive babies were identified between 2005 and 31 March 2017. In France between the beginning of the national program in 1995 and 2016, 5.4 million newborns have been screened and 7,644 of tested newborns were diagnosed with SCD.
Many African countries (except Egypt) have no national newborn screening program. Pilot screening programs have been carried out in Ghana, Benin, Burkina Faso, DR Congo, Gabon, Uganda, Mali, and Tanzania for several years and need to be up scaled nationally.
TREATMENT
Bone marrow transplantation is curative but requires donor hematopoietic stem cells from a histocompatible donor.
Hydroxyurea is one of the pharmacologic therapies for SCD, used in both adults and children. L-glutamine (Endari), was approved by the FDA for treatment of SCD in 2017.
GENE THERAPY
Recent progress on the molecular genetics of haemoglobin expression and gene therapy offers new hope to SCD patients. Twelve clinical trials studying gene therapy to treat sickle cell anemia are now ongoing.