Publications by authors named "Stephen Akafo"
Primary open-angle glaucoma (POAG), the leading cause of irreversible blindness worldwide, disproportionately affects individuals of African ancestry. We conducted a genome-wide association study (GWAS) for POAG in 11,275 individuals of African ancestry (6,003 cases; 5,272 controls). We detected 46 risk loci associated with POAG at genome-wide significance.
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- The study aimed to assess the thickness of the macular retina and central choroid in a group of Ghanaians and compare these measurements to those of individuals with European and other African ancestries.
- It involved 42 Ghanaians, 37 Europeans, and an additional 1,427 subjects of African ancestry, using OCT scans to gather data on retinal thickness.
- Results showed that Ghanaians' macular retina and central choroid were significantly thinner than those of Europeans, with age and sex also influencing thickness, highlighting that established norms for retinal thickness may not apply to all populations.
Article Synopsis
- - A study was conducted to examine vitreomacular interface abnormalities (VMIA) using SD-OCT in Ghanaian adults aged 50 and older, focusing on their correlation with age-related macular degeneration (AMD) grade.
- - Out of 718 participants, 624 (mainly females) had their eye health assessed, revealing that a majority displayed no posterior vitreous detachment (PVD), while only a small percentage exhibited VMIA.
- - Results indicated that VMIA are prevalent among Africans, but PVD appears less common compared to Caucasians, and there was no significant link found between VMIA and AMD grade.
Article Synopsis
- West African crystalline maculopathy (WACM) features crystal-like deposits in the macula, with a study analyzing its characteristics and possible biological factors among a group of participants with this condition.* -
- The study involved 53 participants, predominantly aged around 68, and utilized various methods including medical histories, exams, and imaging to evaluate the presence and distribution of crystals.* -
- Findings showed WACM in 106 eyes with a notable link to the complement factor H (CFH) 402H genetic variant, while factors such as age and sex showed no significant associations.*
Article Synopsis
- Primary open-angle glaucoma (POAG) is a heritable eye condition leading to blindness and the study involved a large genetic analysis of over 34,000 patients and nearly 350,000 controls from different ethnic backgrounds.
- Researchers identified 44 new genetic risk factors for POAG and confirmed 83 previously known ones, finding consistent impacts across various ancestries.
- The study also suggests that certain genes could play significant roles in the disease's development, indicating potential new drug treatments targeting these genetic risk factors.
Article Synopsis
- The study aimed to analyze the foveal pit structure in a Ghanaian population and compare it with a Caucasian group, assessing age-related changes in both.
- Optical coherence tomography scans of 84 Ghanaians and 37 Caucasians were used to measure the foveal pit's depth, width, slope, and volume, factoring in variables like age, sex, and ethnicity.
- Results revealed significant differences in the foveal morphology between the two groups, with Ghanaians exhibiting greater width and volume, especially in women, highlighting the importance of these anatomical variations in understanding retinal diseases among different ethnicities.
Article Synopsis
- Primary open-angle glaucoma is more common and severe in people of African descent compared to those of European or Asian ancestry, yet they are often overlooked in genetic research on this condition.
- The study conducts a genome-wide association study (GWAS) involving nearly 10,000 participants from various countries to identify genetic links to the disease.
- Results suggest significant genetic variants associated with primary open-angle glaucoma, highlighting the need for more focused research on affected populations for better understanding and treatment options.
Aim: To evaluate the safety of 1.25mg and 2mg intravitreal ziv-aflibercept (IVZ) in Ghanaian eyes with choroido-retinal vascular diseases.
Design: Prospective, randomised, double blind, interventional study.
Purpose: To compare the anatomic and visual outcome of scleral buckle (SB) surgery in Korle Bu Teaching Hospital between 2002 and 2005 and 2011 and 2014.
Materials And Methods: In this retrospective comparative study, the medical records of patients who have undergone SB for rhegmatogenous retinal detachment from January 2002 to December 2005 (group A) and from January 2011 to December 2014 (group B) in Korle Bu Teaching Hospital were examined. The clinical history, surgical techniques, and outcomes of treatment were analyzed.
Article Synopsis
- Primary open angle glaucoma (POAG) has a significant genetic component and shows varying prevalence among ethnic groups, being notably more common in black African populations.
- A genome-wide association study involving Tanzanian, South African, and African American samples identified a confirmed association with the TXNRD2 gene and revealed a genetic risk score linked to 15 previously known POAG loci.
- Additionally, a novel genetic locus associated with POAG was identified (EXOC4), but efforts to validate this finding in West African populations faced challenges due to genetic diversity, indicating the need for larger studies to better understand POAG in these groups.
Investigation of known genetic risk factors for primary open angle glaucoma in two populations of African ancestry.
Invest Ophthalmol Vis Sci
September 2013
Purpose: Multiple genes have been associated with primary open angle glaucoma (POAG) in Caucasian populations. We now examine the association of these loci in populations of African ancestry, populations at particularly high risk for POAG.
Methods: We genotyped DNA samples from two populations: African American (1150 cases and 999 controls) and those from Ghana, West Africa (483 cases and 593 controls).
Purpose: Prevalence rates for primary open-angle glaucoma (POAG) are significantly higher in Africans than in European or Asians. It has been reported recently that mitochondrial DNA (mtDNA) lineages of African origin, excluding L2, conferred susceptibility to POAG in Saudi Arabia. This prompted us to test the role of mtDNA haplogroups in the incidence of POAG in the Ghanaian population who has a high frequency of L2 lineages.
View Article and Find Full Text PDFDNA copy number variants (CNVs) have been reported in many human diseases including autism and schizophrenia. Primary Open Angle Glaucoma (POAG) is a complex adult-onset disorder characterized by progressive optic neuropathy and vision loss. Previous studies have identified rare CNVs in POAG; however, their low frequencies prevented formal association testing.
View Article and Find Full Text PDFPrimary open-angle glaucoma (POAG) is the most common form of glaucoma and one of the leading causes of vision loss worldwide. The genetic etiology of POAG is complex and poorly understood. The purpose of this work is to identify genomic regions of interest linked to POAG.
View Article and Find Full Text PDFPurpose: To determine the magnitude and pattern of ocular manifestations in sickle cell disease at Korle-bu Hospital, Accra, Ghana.
Methods: Hospital-based cross-sectional study including all patients with sickle cell disease reporting for routine follow-up at the Sickle Cell Clinic at Korle-bu Hospital, Accra, Ghana.
Results: A total of 201 patients with sickle cell disease (67 male and 134 female) were enrolled, comprising 114 subjects with genotype HbSS, aged 6-58 years, mean 19.
Purpose: Coding variants in the optineurin gene (OPTN, GLC1E) have been reported to play a role in primary open-angle glaucoma (POAG) in various populations. This study investigated the role of OPTN sequence variants in patients with POAG in Ghana (West Africa).
Methods: This is a case-control study of unrelated Ghanaian POAG cases and non-glaucomatous controls.
Purpose: Significant association has recently been reported between pseudoexfoliation glaucoma (XFG) and two single-nucleotide polymorphisms (SNPs), rs3825942, and rs1048661, in the lysyl oxidase-like 1 gene (LOXL1). The purpose of this study was to investigate whether XFG-associated variants of LOXL1 play a significant role in primary open-angle glaucoma in the Caucasian, African-American, and Ghanaian (West-African) populations.
Methods: POAG was defined as the presence of glaucomatous optic nerve damage, associated visual field loss, and elevated intraocular pressure (>22 mm Hg in both eyes).
Purpose: In addition to chronic hyperglycemia, there is increasing evidence that genetic factors may be important in the development of diabetes retinopathy (DR). Specifically, polymorphisms of the endothelial nitric oxide synthase gene (eNOS) have been reported to be associated with multiple health conditions including DR, hypertension, nephropathy, and cardiovascular diseases in several ethnic groups. However, there is a paucity of similar data in African Americans and other African populations.
View Article and Find Full Text PDFPurpose: High intraocular pressure (IOP) is a major risk factor for glaucoma, one of the leading causes of blindness worldwide. Because it has been demonstrated that African populations are at increased risk for glaucoma, the authors investigated the genetic basis of IOP in a sample of West Africans with type 2 diabetes (T2D) from Ghana and Nigeria.
Methods: Genomewide linkage analysis was conducted for loci linked to IOP (measured by applanation tonometry) in 244 affected sibling pairs with T2D using 372 autosomal short-tandem repeat markers at an average spacing of 9 cM.
Two membrane-based ELISA systems were used in detecting Toxoplasma antigens and anti-Toxoplasma antibodies in urine samples collected from 54 ophthalmology (22 suggestive active and 32 suggestive past infection) patients and 26 pregnant women attending obstetrics/gynaecology clinic (OGP), suspected of toxoplasmosis by eye examination, past medical records and questionnaire, respectively, in Ghana from mid-February to April 2002. The antigen detecting ELISA was able to demonstrate antigen in 100% (22/22) ophthalmology (active infection) and 62.5% (20/32) ophthalmology (past infection) patients, and 42% (11/26) of OGP which included 3 that were sero-negative prior to and during this study, giving an overall prevalence of 66.
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