SICKLE CELL DISEASE Sickle Cell Disease in African-American People

Abstract

Sickle-cell disease (SCD) is associated with neurological complications including brain perfusion deficits and tissue infarction, which can lead to cognitive deficits early in life. Timely assessment and detection of these deficits is critical for effective intervention. Biological measures of disease severity may serve as clinical markers of neurological complications; however the relationship between such markers and cognitive deficits in this population remains unclear. Mixed evidence for the relationship may have resulted due to the use of too few measures to assess a broad and complicated construct. Moreover, most studies have considered each measure in isolation rather than in combination with other clinical markers. Lastly, recent evidence suggests that SCD may consist of two clinical sub-phenotypes, whereas previous studies have treated SCD severity as a unitary construct. This research aims to examine the relationship between biological measures of disease severity and cognitive deficits in African-Americans with SCD.

Table of Contents

Abstract2

Introduction4

Key words5

Description and Analysis6

Research Question8

Hypothesis for the Research8

Aim and Objective8

Background and Significance8

Sickle-Cell Epidemiology and Pathophysiology9

Neurocognitive Impairments in SCD9

Biological Markers of Disease Severity10

Methods13

Subjects or Participants13

Materials13

Procedures14

Data Analysis14

Budget Allocation14

Data Interpretation and Conclusions15

Bibliography16

Sickle Cell Disease in African-American People

Introduction

Sickle Cell Disease (SCD) is the most common genetic disorder in the African-American community with an estimated 12,000 affected individuals. The disease distribution showed wide variation but it is noteworthy that 80% of all admissions involved patients in the two most deprived quintiles of the population. SCD is particularly common in people of African-Caribbean and African origin and, to a lesser extent, in those whose ancestors come from the Mediterranean region, the Middle East or Asia. This geographical susceptibility reflects the fact that the sickle cell trait - the normal gene 'A' carried along with the sickle gene 'S' - confers a survival advantage against falciparum malaria (the most common form of malaria) during a critical period.

SCD is an autosomal recessive genetic disorder caused by a single point mutation, resulting in the production of an abnormal form of hemoglobin (hemoglobin S or Hb S). The term sickle cell disease is used to refer to disease caused by the homozygous state (Hb SS), also known as sickle cell anemia, and that caused by the heterozygous condition in which the Hb S gene is co-inherited with another form of abnormal hemoglobin (for example, Hb C, Hb D Punjab, Hb O Arab, Hb Lepore or the gene that causes beta-(ß) thalassaemia). In individuals with ß-thalassaemia, mutation of the ß-globin gene results in reduction or total inability to produce the normal ß-globin chain of haemoglobin. If this gene is inherited with the sickle cell gene (Hb S), a sickle cell disorder results. This group of heterozygous genetic conditions causes clinically significant SCD. Hb SS (the homozygous state) is the most common and severe form, accounting for 70% of patients with SCD in the region, while the compound heterozygous form Hb SC accounts for the majority of the remaining 30% of patients with SCD.

Key words

Cognitive deficit: Cognitive deficit is an inclusive term to describe any characteristic that acts ...