ApoE genetic variation is associated with differential susceptibility to dyslipidaemia and type 2 diabetes in black Africans

Abstract

BackgroundDyslipidaemia in type 2 diabetes mellitus (T2DM) is characterized by a biochemical lipid triad of low HDL‐cholesterol, raised triglycerides, and small, dense low‐density lipoprotein (LDL) particles. Studies on ApoE genetic variation influence in the development of dyslipidaemia in African diabetic patients are few.Aims and ObjectivesThis study aimed to evaluate the role of genetic variation in ApoE coding gene on dyslipidaemia in South African diabetic patients.MethodsTwo hundred and forty‐four (n=244) participants were retrospectively recruited from the Baragwanath diabetic clinic. These comprised of two groups: (i) dyslipidaemic, and (ii) non‐dyslipidaemic (controls). The dyslipidaemic group was further divided into three groups according to; i) high cholesterol only; ii) high triglycerides only; and, iii) both high cholesterol and high triglycerides (referred to as the mixed group). Ethical clearance was obtained from the University of Cape Town and Baragwanath/Wits University. Genetic characterisation of ApoE was accomplished using polymerase chain reaction/restriction fragment length polymorphism (RFLP), confirmed by Sanger sequencing.ResultsOf the 244 participants, 165 were dyslipidaemic while 79 were not. A significant (p <0.0001) finding in this study is that ApoE2/3 dyslipidaemic participants had a distribution of only 5.3%, compared to 20.6% among the non‐dyslipidaemic participants. There was a low frequency distribution, 1.8% of among ApoE2/4 among the diabetic participants. There a significant association between HbA1c and age (p=<0.008). TC (p=0.00092), LDL (p=0.0184) and triglycerides (p=0.0175) were strongly associated with poor glycaemic control. Both LDL (p=0.0174 and HDL (p=0.0072) were associated with age.ConclusionsThe study showed the effects of ApoE genetic variation on the dyslipidaemia seen in black South African diabetic participants. The study showed that diabetic dyslipidaemia is genetically influenced by Apo E. ApoE2/3 DM patients had a reduced risk of developing dyslipidaemia while ApoE2/4 was associated with reduced risk for T2DM. Therefore, exploration of possible underlying genetic predisposition in dyslipidaemic T2DM patients who respond poorly to standard therapy is recommended.Support or Funding InformationDepartmental support