THE EFFECT OF STRUCTURAL VARIATION IN THE DELTA-5-DESATURASE GENE ON SEVERITY OF SICKLE CELL ANAEMIA

THE EFFECT OF STRUCTURAL VARIATION IN THE DELTA-5-DESATURASE GENE ON SEVERITY OF SICKLE CELL ANAEMIA

Abstract

Background: Sickle Cell Disease (SCD) is a hereditary chronic haemolytic anaemia with worldwide
impact on health and longevity. Sickle cell anaemia (homozygous S gene) is caused by a single
missense mutation in the β-globin gene on chromosome 11. At the protein level, sickle haemoglobin
arises from a single amino acid substitution (GTG for GAG) at codon 6 of the beta globin gene that
results in substitution of valine for glutamic acid.
Methods: this research is aimed at determining the relationship between structural variation in the gene
for FADS 1 and the severity of sickle cell disease. A total of 50 patients were studied: 25 were severe
cases categorized by the criteria listed in the methods section, and 25 non-severe cases who did not
exhibit features of severe disease complications. Venous blood (total of 10mls) anticoagulated in
ethylene diamine tetraacetic acid (EDTA )and lithium heparin was collected from paediatric and adult
sickle cell anaemia patients. The following tests were carried out: full blood count, liver function test,
renal function test, DNA extraction and sequencing.
Results: There were 25 subjects in the severe group (test group), 18 males and 7 females aged between
5 and 49 years. The non-severe group (control group) was made up of 18 females and 7 males within the
same age range as the test group.
The P-values for physical parameters are: height (cm) 0.338, weight (kg) 0.353 and BMI (kg/m2)0.423.
The P-values for haematological parameters are platelet count 0.234, white cell count 0.202 and
haemoglobin concentration 0.034.
The P-values for the biochemical parameters are LDH 0.32, urea <0.001 and Creatinine <0.001.
There was no difference in the sequenced Single Nucleotide Polymorphism (SNP) genotype between
those in non-severe group and those in the severe group.
Logistic regression models that were used to check for the association between disease severity and
SNPs on FADS1 gene were not statistically significant. P-value = 0.069 for rs17458 and P value = 0.96
for rs 174566
Conclusion: It is shown in this study that structural variation in the delta-5-desaturase gene was
observed not to account for the severity of sickle cell anaemia.

THE EFFECT OF STRUCTURAL VARIATION IN THE DELTA-5-DESATURASE GENE ON SEVERITY OF SICKLE CELL ANAEMIA

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