High population frequencies of APOL1 risk variants are associated with increased prevalence of non-diabetic chronic kidney disease in the Igbo people from south-eastern Nigeria.

BACKGROUND: Continental Africa is facing an epidemic of chronic kidney disease (CKD). APOL1 risk variants have been shown to be strongly associated with an increased risk for non-diabetic kidney disease including HIV nephropathy, primary non-monogenic focal and segmental glomerulosclerosis, and hypertension-attributed nephropathy among African ancestry populations in the USA. The world's highest frequencies of APOL1 risk alleles have been reported in West African nations, overlapping regions with a high incidence of CKD and hypertension. One such region is south-eastern Nigeria, and therefore we sought to quantify the association of APOL1 risk alleles with CKD in this region. METHODS: APOL1 risk variants were genotyped in a case-control sample set consisting of non-diabetic, CKD patients (n = 44) and control individuals (n = 43) from Enugu and Abakaliki, Nigeria. RESULTS: We found a high frequency of two APOL1 risk alleles in the general population of Igbo people of south-eastern Nigeria (23.3%). The two APOL1 risk allele frequency in the CKD patient group was 66%. Logistic regression analysis under a recessive inheritance model showed a strong and significant association of APOL1 two-risk alleles with CKD, yielding an odds ratio of 6.4 (unadjusted p = 1.2E-4); following correction for age, gender, HIV and BMI, the odds ratio was 4.8 (adjusted p = 5.1E-03). CONCLUSION: APOL1 risk variants are common in the Igbo population of south-eastern Nigeria, and are also highly associated with non-diabetic CKD in this area. APOL1 may explain the increased prevalence of CKD in this region.

High degree of duodenal inflammation in Nigerians with functional dyspepsia.

BACKGROUND: Functional dyspepsia (FD) is a heterogeneous disorder associated with diverse pathophysiological mechanisms, including immune activation and low-grade mucosal inflammation. Genetic factors, physiological functions, and environmental factors may determine the relative importance of various pathophysiological mechanisms. This study was designed to determine the histological alterations in the duodenal mucosa of Nigerian patients with FD. METHODS: Consecutive patients with dyspepsia seen over a 27-month period in two gastrointestinal endoscopy facilities in Enugu, South-East Nigeria were further evaluated with upper gastrointestinal endoscopy and duodenal mucosal biopsies if no lesion was found in the upper gastrointestinal tract. Patients with heartburn and/or regurgitation who did not have any dyspeptic symptoms and did not have any lesion in the upper gastrointestinal tract on endoscopy were presumed to have non-erosive reflux disease (NERD) and they served as controls. The control subjects also had duodenal biopsies. The histopathological findings in the cases and controls were compared. RESULTS: There were 68 patients with FD and 52 patients with NERD. The total inflammatory score was 242 in FD and 66 in NERD (Mann-Whitney U =1168, P=0.0011). Similarly, the scores for chronic inflammation, gastric metaplasia, neutrophilic activity, eosinophilic infiltration, and Helicobacter pylori were significantly higher in FD than NERD. CONCLUSION: Functional dyspepsia is associated with a high degree of inflammation in the duodenal mucosa. This may reflect the high prevalence of gastrointestinal infections in a tropical environment such as Nigeria. These findings may have therapeutic potential that further studies might elucidate.