African Population Research Articles

Studying eruption patterns of mandibular third molars for forensic age assessment: Introducing current reference data from a population of black South Africans.

Evaluation of the eruption of mandibular third molars in orthopantomograms (OPGs) is a method of forensic age assessment. The objective of our study was to provide valid reference data for this trait within a population of black South Africans. The study was guided by the criteria for reference studies in age assessment. A study population from Pretoria, South Africa comprising 670 OPGs obtained from 338 black females and 332 black males aged between 15.00 and 25.97 years was analysed. All OPGs were performed for medical indication during the period from 2011 to 2022 and were retrospectively evaluated. From the 670 OPGs, a total of 1021 mandibular third molars were evaluated. The assessment of mandibular third molars was conducted using the staging scale presented by Olze et al. in 2012. Two experienced dentists evaluated the OPGs independently of each other. If the two examiners diverged in their assessments, a consensus stage was assigned. As expected, the mean, median and minimal age increased with higher stages for both teeth and both sexes. The minimum age recorded for stage D, indicating complete tooth eruption, was 15.79 years in females and 16.62 years in males. As it is the case for previous reference studies in other countries, placing exclusive reliance on the evaluation of mandibular third molar eruption is inadequate for ascertaining the age of majority among Black South Africans. Future studies need to examine if our results are transferable to other countries in Sub-Saharan Africa.

The Quadrangular Cartilage in Rhinoplasty: A Surgically Focused CT Dimensional Analysis of Black African and Caucasian Populations.

The apparent lack of quadrangular cartilage in Black African noses is commonly observed both from a radiological and clinical point of view. To the best of our knowledge, only a few research papers have been conducted on the facial proportions and structural anatomy of black people of Southern and Eastern Africa. The aim of this retrospective comparative study is a radiological assessment of the total amount of septal quadrangular cartilage by measuring its area in sagittal CT views, in two selected Black South African and Caucasian (CA) samples and the comparison with the literature in our hands. Statistical analysis was conducted, categorical variables are shown as frequencies and percentages, while continuous variables as means and standard deviations. Normal distribution of variables was verified using the Shapiro-Wilk test or by means of skewness and kurtosis values. Differences among unpaired groups were evaluated using the independent Student's t-test for normally distributed data (complemented by the Cohen's d to show the effect size with the following cutoff: d = 0.2, "small" effect size; d = 0.5, "medium" effect size; d = 0.8, "large" effect size) and Mann-Whitney U test in case of non-normal distribution. Statistical significance was defined as p < 0.05 setting the α-error probability at 5%. This study shows that, on average, there is 30% more cartilage available in CA compared with Black African noses and confirms the apparent lack of quadrangular cartilage and in Black African noses which is commonly observed in surgery. The need for an adequate amount of autologous septal cartilage makes cartilage availability a major concern before surgery and being able to preoperative accurately measure the amount of septal cartilage that is available to be harvested for other grafts in the surgery is essential.

Whole-genome resequencing deciphers patterns of genetic diversity, phylogeny, and evolutionary dynamics in Kashmir cattle.

Kashmir cattle, which were kept by local pastoralists for centuries, are exceptionally resilient and adaptive to harsh environments. Despite its significance, the genomic characteristics of this cattle breed remain elusive. This study utilized whole genome sequences of Kashmir cattle (n = 20; newly sequenced) alongside published whole genomes of 32 distinct breeds and seven core cattle populations (n = 135). The analysis identified ~25.87 million biallelic single nucleotide polymorphisms in Kashmir cattle, predominantly in intergenic and intron regions. Population structure analyses revealed distinct clustering patterns of Kashmir cattle with proximity to the South Asian, African and Chinese indicine cattle populations. Genetic diversity analysis of Kashmir cattle demonstrated lower inbreeding and greater nucleotide diversity than analyzed global breeds. Homozygosity runs indicated less consanguineous mating in Kashmir cattle compared with European taurine breeds. Furthermore, six selection sweep detection methods were used within Kashmir cattle and other cattle populations to identify genes associated with vital traits, including immunity (BOLA-DQA5, BOLA-DQB, TNFAIP8L, FCRL4, AOAH, HIF1AN, FBXL3, MPEG1, CDC40, etc.), reproduction (GOLGA4, BRWD1, OSBP2, LEO1 ADCY5, etc.), growth (ADPRHL1, NRG2, TCF12, TMOD4, GBP4, IGF2, RSPO3, SCD, etc.), milk composition (MRPS30 and CSF1) and high-altitude adaptation (EDNRA, ITPR2, AGBL4 and SCG3). These findings provide essential genetic insights into the characteristics and establish the foundation for the scientific conservation and utilization of Kashmir cattle breed.

The prevalence of human papillomavirus in ocular surface squamous neoplasia in HIV positive and negative patients in a South African population.

To assess the prevalence and subtypes of Human Papillomavirus (HPV) in Ocular Surface Squamous Neoplasia (OSSN) in Human Immunodeficiency Virus (HIV) positive and negative patients in South Africa. This study was a single center retrospective cross-sectional study, conducted at Tygerberg Hospital, Western Cape, South Africa. We assessed 63 histopathologically confirmed OSSN formalin-fixed paraffin-embedded (FFPE) tissue blocks from 2015-2023. The presence of HPV was determined using the Hybrispot Direct Flow Chip Kit. Corresponding clinical data was retrieved from the National Health Laboratory Service (NHLS) central data warehouse. Of the confirmed OSSN samples, 66.7% tested positive for HPV (95% confidence interval [CI] 54-77.3%). Of the 42 HPV positive samples, 38 (90.5%) had one or more known genotypes detected and 4 had unknown genotypes. The most prevalent subtypes were HPV 11, 16 and 18 (found in 61.9%, 52.4% and 33.3% of HPV positive samples respectively). 88.9% of the lesions biopsied were from HIV positive patients, of whom 56.4% had a CD4 + count of < 200 cells/µL. A lower median CD4 + count was detected among HIV positive patients with invasive squamous cell carcinoma compared to those with moderate dysplasia (p < 0.0198). There is a high prevalence of HPV in OSSN in South Africa. Certain subtypes namely, 11, 16, 18, 31, 33 and 35 may be more carcinogenic. HIV with HPV co-infection may be linked as a causative factor in the development of OSSN.

The Value of Adding Exosome-Based Prostate Intelliscore to Multiparametric Magnetic Resonance Imaging in Prostate Biopsy: A Retrospective Analysis

Introduction: Currently, there is limited evidence for the relationship of Exosome-based Prostate Intelliscore (EPI) and multiparametric magnetic resonance imaging (mpMRI) in stratifying risk for clinically significant prostate cancer. Using a retrospective cohort study design, we sought to characterize the relationship between these two noninvasive metrics and prostate biopsy outcome. Methods: Data were collected via electronic medical record for all patients who underwent EPI testing from 1 January 2019 to 3 February 2022 and had available medical records at a single mid-western university medical center. Positive test result was defined as &gt;15.6 for EPI, ≥3 PI-RADS score and ≥3 + 4 Gleason Score for biopsy findings. Utility of EPI, mpMRI and combined use was characterized through calculation of sensitivity, specificity, positive predictive value, negative predictive value, and ROC analysis. Results: A total of 226 patients were identified as receiving EPI testing for risk stratification of clinically significant prostate cancer. Sensitivity for EPI was 91%, mpMRI was 90%, and the highest was combined use at 96%. With ROC analysis, AUC for EPI alone was 0.57 (95% CI, 0.47–0.67) and 0.78 (95% CI, 0.70–0.87) for mpMRI alone. With prior positive EPI result, AUC for combined use with mpMRI was 0.80 (95% CI, 0.71–0.89). Further subgroup analysis resulted in increased AUC values of EPI 0.67 (95% CI, 0.48–0.87), mpMRI 0.90 (95% CI, 0.76–1.0), and combined 0.90 (95% CI, 0.75–1.0) in the African American population. Discussion: We observed that the combined use of EPI and mpMRI led to an avoided biopsy in 43% of patients. Using both parameters increased the overall sensitivity and diagnostic accuracy in detecting clinically significant prostate cancer. The best test performance was observed in the African American cohort. Identifying optimal noninvasive tools to assess risk for prostate cancer is crucial to providing accurate and cost-effective care. Future study should utilize a prospective study design to further support the combined use of these metrics.

High SARS-CoV-2 incidence and asymptomatic fraction during Delta and Omicron BA.1 waves in The Gambia

Little is known about SARS-CoV-2 infection risk in African countries with high levels of infection-driven immunity and low vaccine coverage. We conducted a prospective cohort study of 349 participants from 52 households in The Gambia between March 2021 and June 2022, with routine weekly SARS-CoV-2 RT-PCR and 6-monthly SARS-CoV-2 serology. Attack rates of 45% and 57% were seen during Delta and Omicron BA.1 waves respectively. Eighty-four percent of RT-PCR-positive infections were asymptomatic. Children under 5-years had a lower incidence of infection than 18-49-year-olds. One prior SARS-CoV-2 infection reduced infection risk during the Delta wave only, with immunity from ≥2 prior infections required to reduce the risk of infection with early Omicron lineage viruses. In an African population with high levels of infection-driven immunity and low vaccine coverage, we find high attack rates during SARS-CoV-2 waves, with a high proportion of asymptomatic infections and young children remaining relatively protected from infection.

Skin colour: A window into human phenotypic evolution and environmental adaptation.

As modern humans ventured out of Africa and dispersed around the world, they faced novel environmental challenges that led to geographic adaptations including skin colour. Over the long history of human evolution, skin colour has changed dramatically, showing tremendous diversity across different geographical regions, for example, the majority of individuals from the expansive lands of Africa have darker skin, whereas the majority of people from Eurasia exhibit lighter skin. What adaptations did lighter skin confer upon modern humans as they migrated from Africa to Eurasia? What genetic mechanisms underlie the diversity of skin colour observed in different populations? In recent years, scientists have gradually gained a deeper understanding of the interactions between pigmentation gene and skin colour through population-based genomic studies of different groups around the world, particularly in East Asia and Africa. In this review, we summarize our current understanding of 26 skin colour-related pigmentation genes and 48 SNPs that influence skin colour. Important pigmentation genes across three major populations are described in detail: MFSD12, SLC24A5, PDPK1 and DDB1/CYB561A3/TMEM138 influence skin colour in African populations; OCA2, KITLG, SLC24A2, GNPAT and PAH are key to the evolution of skin pigmentation in East Asian populations; and SLC24A5, SLC45A2, TYR, TYRP1, ASIP, MC1R and IRF4 significantly contribute to the lightening of skin colour in European populations. We summarized recent findings in genomic studies of skin colour in populations that implicate diverse geographic environments, local adaptation among populations, gene flow and multi-gene interactions as factors influencing skin colour diversity.

Ancestry of the major long-range regulatory site of the α-globin genes in the Portuguese population with the common 3.7 kb α-thalassemia deletion

BackgroundThe α-Major Regulatory Element (α-MRE), also known as HS-40, is located upstream of the α-globin gene cluster and has a crucial role in the long-range regulation of the α-globin gene expression. This enhancer is polymorphic and several haplotypes were identified in different populations, with haplotype D almost exclusively found in African populations. The purpose of this research was to identify the HS-40 haplotype associated with the 3.7 kb α-thalassemia deletion (-α3.7del) in the Portuguese population, and determine its ancestry and influence on patients’ hematological phenotype.Methods and resultsWe selected 111 Portuguese individuals previously analyzed by Gap-PCR to detect the presence of the -α3.7del: 50 without the -α3.7del, 34 heterozygous and 27 homozygous for the -α3.7del. The HS-40 region was amplified by PCR followed by Sanger sequencing. Four HS-40 haplotypes were found (A to D). The distribution of HS-40 haplotypes and genotypes are significantly different between individuals with and without the -α3.7del, being haplotype D and genotype AD the most prevalent in patients with this deletion in homozygosity. Furthermore, multiple correspondence analysis revealed that individuals without the -α3.7del are grouped with other European populations, while samples with the -α3.7del are separated from these and found more closely related to the African population.ConclusionThis study revealed for the first time an association of the HS-40 haplotype D with the -α3.7del in the Portuguese population, and its likely African ancestry. These results may have clinical importance as in vitro analysis of haplotype D showed a decrease in its enhancer activity on α-globin gene.

The Africa non-communicable diseases (NCD) Open Lab: Impact of a portfolio of clinical studies to deepen the understanding of NCDs in sub-Saharan Africa.

Clinical research in sub-Saharan Africa (SSA) has often focussed on communicable diseases. However, with the increasing burden of non-communicable diseases (NCDs), there is a need for Africa-specific NCD research. GSK established the Africa NCD Open Lab in 2014. Three calls for proposals were advertised through various media channels. An external independent scientific advisory board, predominantly representing African scientists and NCD experts, reviewed and selected projects to receive funding. An additional programme in the Africa NCD Open Lab was designed to build statistical capability by supporting training initiatives. We assessed the impact of the Africa NCD Open Lab in three ways: scientific quality with impact; research training and professional development; and research environments. We captured metrics through regular reports/interactions with researchers; via a final report; and through exit interviews with principal investigators. Twenty projects in 11 African countries were funded; reports from 18 completed projects are available (data capture is ongoing). Overall, 139 articles have been published in peer-reviewed journals and other data have been presented at conferences and other forums. Most completed projects led to positive outcomes, such as further research, informing policy, or positively impacting clinical care, including three projects that saw changes to regional or national practice guidelines: the CREOLE study in Nigeria; the African Severe Asthma Program in Uganda; and the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension in South Africa. Participation in the Africa NCD Open Lab led to the award of 34 grants related to or influenced by increased research capacity or experience. Significant professional development related to the projects also occurred with higher-level degrees being awarded, including 30 MScs, 30 PhDs, and nine postdoctoral fellowships. Through these projects, research capacity was strengthened across the region by equipping core research facilities, training research staff, strengthening research support services, and supporting the expansion of investigator networks. The completed Africa NCD Open Lab projects demonstrate high-quality research outcomes addressing important health challenges with potential benefits to African populations. Based on the success of the Africa NCD Open Lab, additional funding has been secured to extend the Open Lab initiative.

Application of Genomic Medicine in Africa: 14th Conference of the African Society of Human Genetics and the 2nd International Congress of the Moroccan Society of Genomics and Human Genetics, Rabat, Morocco 2022.

The 14th African Society of Human Genetics (AfSHG) Morocco Meeting and 2nd International Congress of the Moroccan Society of Genomics and Human Genetics (SM2GH), held in Rabat, Morocco, from December 12 through 17, 2022, brought together 298 attendees from 23 countries, organized by the AfSHG in collaboration with the SM2GH. The conference's overarching theme was "Applications of Genomics Medicine in Africa," covering a wide range of topics, including population genetics, genetics of infectious diseases, hereditary disorders, cancer genetics, and translational genetics. The conference aimed to address the lag in the field of genetics in Africa and highlight the potential for genetic research and personalized medicine on the continent. The goal was to improve the health of African populations and global communities while nurturing the careers of young African scientists in the field. Distinguished scientists from around the world shared their recent findings in genetics, immunogenetics, genomics, genome editing, immunotherapy, and ethics genomics. Precongress activities included a 2-day bioinformatics workshop, "NGS Analysis for Monogenic Disease in African Populations," and a Young Investigators Forum, providing opportunities for young African researchers to showcase their work. The vast genetic diversity of the African continent poses a significant challenge in investigating and characterizing public health issues at the genetic and functional levels. Training, research, and the development of expertise in genetics, immunology, genomics, and bioinformatics are vital for addressing these challenges and advancing genetics in Africa. The AfSHG is committed to leading efforts to enhance genetic research, coordinate training, and foster research collaborations on the continent.

Correlation of growth differentiation factor-5 + 104T>C polymorphism with the risk of knee, hand, and hip osteoarthritis: a case-control study and meta-analysis based on 47 case-control studies

Osteoarthritis (OA) arises from a intricate interplay of genetic and environmental factors. Numerous studies have explored the link between the growth differentiation factor 5 (GDF-5) +104T>C polymorphism and OA risk, but the findings have been inconclusive. We carried out a case-control study with 704 OA cases and 418 healthy controls. Furthermore, we conducted a meta-analysis by thoroughly searching the literature for relevant studies published until 1 September, 2023. The combined odds ratio and 95% confidence intervals were used to assess the correlation’s strength. A total of 47 independent case-control studies, including 17,602 OA cases and 30,947 controls, were analyzed. Of these, 31 studies (11,176 cases, 16,724 controls) focused on knee OA, 8 studies (3,973 cases, 8,055 controls) examined hip OA, and 6 studies (2244 cases, 5965 controls) investigated hand OA. Overall, our findings suggest that the GDF-5 + 104T>C polymorphism has a protectibe role in development of OA in global scale. Subgroup analyses by ethnicity indicated that this genetic variation provides protection against OA in Caucasian, Asian, and African populations. Further subgroup analysis based on the type of OA showed a decreased risk of knee and hand OA associated with this variation, but not for hip OA. Our combined data indicates that the GDF-5 + 104T>C polymorphism offers protection against the development of OA in general, as well as knee and hand OA. Nevertheless, there was no correlation found between this polymorphism and the development of hip OA.

Abstract PO2-28-04: Pregnancy-associated relapse of triple-negative breast cancer

Abstract Introduction: Pregnancy Triple-negative breast cancer(TNMC) is the absence of ER PR and HER2 receptor expression. It constitutes about 15-20% of all breast cancers and is known to be the aggressive form with a high relapse rate (1). Interestingly, it usually affects women aged &amp;lt; 40 and has a low survival rate in African-American females. This case is a typical presentation of a 38-year-old young woman with PMH of T2NO right triple-negative breast cancer diagnosed in 2017 s/p right mastectomy with sentinel LN biopsy, received immunotherapy and chemotherapy, has been cancer-free for two years, and developed metastatic cancer during her pregnancy. In this case, we understand the diagnostic and therapeutic challenges of TNBC during pregnancy. Case: A 38-year-old African American woman, G0, T2NO triple negative invasive ductal carcinoma, underwent a right breast mastectomy and sentinel LN biopsy. She received treatment with (Anti-PD-L1 Antibody) concomitant with weekly paclitaxel and Doxorubicin/Cyclophosphamide (AC) chemotherapy. However, she had a residual 4cm tumor for which she was treated with adjuvant therapy with capecitabine for six months. A repeat Mammogram in 2019 showed no evidence of malignancy. In 2021, the patient was G2P2L1, admitted to the hospital after having a seizure. CT reported cystic/necrotic left parietal lesion mass effect with 8mm right-sided midline shift with metastasis to lungs and abdominal wall. She underwent L parietal craniectomy with resection of the tumor. At 32 weeks of gestation , chemotherapy with carboplatin and paclitaxel was given after her C-section and Gamma knife radiosurgery for metastatic lesions. She developed super refractory seizures, was induced into a coma with therapeutically anesthetic agents, and passed eventually. Discussion: Little literature exists on pregnancy-associated relapse of triple-negative breast cancer and its deterioration. Our patient was in remission for two years and was diagnosed with metastatic cancer during her second pregnancy. John et al., (2018) discussed an interesting association between breastfeeding, parity, and occurrence of TNBC, that there is a two-fold increased risk of developing TNBC with high parity(3 full-term pregnancies) and short-term breastfeeding (&amp;lt; 12 months) (2). Studies have also shown that cancers during or postpartum pregnancy are aggressive with more tumor burden and metastasize to the lungs, liver, and brain, which is consistent with our patient. (3) Conclusion: Pregnancy-associated breast cancer is diagnostically and therapeutically challenging during or in the postpartum period and with a high propensity of the triple-negative type. It requires a multidisciplinary team approach, awareness in the African American population, clinical suspicion of breast mass during pregnancy warrants imaging, and prolonged breastfeeding postpartum. Diagnosis is usually delayed due to pregnancy, and more research is needed on the diagnostic modalities during pregnancy for early treatment initiation. References Almansour NM. Triple-Negative Breast Cancer: A Brief Review About Epidemiology, Risk Factors, Signaling Pathways, Treatment and Role of Artificial Intelligence. Front Mol Biosci. 2022 Jan 25;9:836417. doi: 10.3389/fmolb.2022.836417. PMID: 35145999; PMCID: PMC8824427. John EM, Hines LM, Phipps AI, et al. Reproductive history, breast-feeding and risk of triple-negative breast cancer: The Breast Cancer Etiology in Minorities (BEM) study. International Journal of Cancer. 2018;142(11):2273. doi:10.1002/ijc.31258 Amant F, Deckers S, Van Calsteren K, Loibl S, Halaska M, Brepoels L, et al. Breast cancer in pregnancy: recommendations of an international consensus meeting. Eur J Cancer (2010) 46(18):3158–68. 10.1016/j.ejca.2010.09.010 Citation Format: Vaidarshi Abbagoni. Pregnancy-associated relapse of triple-negative breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-28-04.

Abstract PS18-09: The DARC side of Breast Cancer - DARC, Duffy-null and African ancestry influence in the Triple Negative Breast Cancer tumor microenvironment

Abstract Background. Despite a recent convergence of breast cancer (BC) incidence rates between African American (AA) and European American (EA) women, AA women continue to have ~40% higher mortality rates. BC is a heterogeneous collection of diseases, where African ancestry women are disproportionately burdened with the most aggressive subtype of BC, triple negative BC (TNBC). We have previously reported that the African ancestry-specific Duffy-null allele (FY-) is a risk factor for TNBC diagnoses. FY- is a promoter variant that removes expression of the Duffy Antigen Receptor for Chemokines (DARC/ACKR1), from red blood cells (RBCs). DARC serves as a portal of entry for Plasmodium vivax malaria parasite, and FY- confers immunity, leading to fixation of FY- among Sub-Saharan African populations. DARC is an atypical chemokine receptor that functions to modulate chemokine levels in circulation and tissues to aid immune cell recruitment. DARC is also expressed on breast tumor epithelial cells, however the significance of DARC in the TNBC tumor microenvironment (TME) has not fully been explored. Leveraging our African ancestry enriched International Study for the Center of Breast Cancer Subtypes cohort and in vivo murine models, we employed multi-omics approaches to explore the function of FY- and DARC expression across cell types in the TNBC TME. Genomics. Using transcriptomic data from the TCGA BC cohort, we have previously reported that DARC expression is highly correlated with deconvoluted immune cell abundance using CIBERSORT. To build upon this finding among TNBC patients, we have analyzed RNAseq data from two cohorts of African ancestry women to explore correlation of DARC expression status and immune cell abundance. Among TNBC cases, we report that higher DARC expression was significantly associated with increased immune cell abundance, with increases in B cell, T cell and monocyte populations. Using whole genome sequencing data across 86 African ancestry cases, we are currently investigating germline FY- status with mutational signatures. Circulating biomarkers. Patient plasma was collected prior to surgery, where Luminex multiplex assays were performed to quantify levels of &amp;gt;40 circulating chemokines and cytokines. FY- status has been determined for ~550 patients using single-plex or multiplex PCR genotyping methods from germline saliva DNA. Our univariate analyses show several circulating chemokines, including CCL2, CXCL2, CXCL6 and CXCL11, have significant differences between FY- and non-FY- BC patients. Curation of clinicopathological variables for multivariate analysis is ongoing. Murine models. We crossed C3(1)Tag BC transgenic mice with a DARC knock-out (KO) line to generate mice lacking DARC expression that spontaneously develop tumors in the mammary fat pads. The C3(1)Tag model is reported to have similar gene expression profiles to basal-like TNBC tumors. Tumors were collected at pre-determined time points of 25 and 30 weeks, where DARC KO mice had increased tumor size and tumor burden at 30 weeks. Initial fluorescent staining revealed an increase in immune cell infiltration in the TME of DARC expressing mice compared to DARC KO mice. To further explore this, we employed multiplex staining across a representative cohort of DARC expressing and KO mice at 25 and 30 weeks to capture the specific immune cell populations infiltrating the TME. Conclusions. TNBC tumors have worse prognosis due to lack of targeted therapeutic options. Increased immunogenicity of TNBC tumors, especially among African ancestry women may be driven in part by DARC expression. Characterization of FY- status, in coordination with DARC among other cell types in the TNBC TME could present new opportunities for biomarker and/or therapeutic development to improve prognosis for these underserved populations. Citation Format: Rachel Martini, Stevens Patino, Emma Guyonnet, Brian Stonaker, Isra Elhussein, Julie Sahler, Avery August, Nancy Manley, Rick Kittles, Clayton Yates, Lisa Newman, Melissa Davis. The DARC side of Breast Cancer - DARC, Duffy-null and African ancestry influence in the Triple Negative Breast Cancer tumor microenvironment [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS18-09.

Lung outcomes and related risk factors in patients after SARS-CoV-2 infection: a hospitalised single-centre cohort from Johannesburg, South Africa

Sequelae post-SARS-CoV-2 infection, including lung and functional impairment, pose a significant challenge post-recovery. We explored the burden and risk factors for post-COVID-19 sequelae in an African population with prevalent comorbidities including tuberculosis (TB) and HIV. We conducted an observational cohort study on hospitalised adults with confirmed SARS-CoV-2 infection from 20 March to 06 October 2021at Chris Hani Baragwanath Academic Hospital, South Africa. We collected data on comorbidities, and COVID-19 severity using the World Health Organization (WHO) clinical progression scale. Prospectively, we followed up all participants within 40-days post-discharge to assess body mass index (BMI), COVID-19 symptoms and quality of life using St George's Respiratory Questionnaire (SGRQ), 6-min walking-test (6MWT), and spirometry. A subsequent in-depth visit assessed plethysmography, diffusing capacity for the lung for carbon monoxide (DLCO), and high-resolution chest-CT. We followed up 111 participants, where 65.8% were female, median age 50.5 years, and predominantly black-African (92.8%). Relevant comorbidities included TB disease (18.9%) and HIV infection (36%). SGRQ total scores were elevated in 78.9%, median 6MWT distance was reduced at 300m (IQR 210-400), and nearly half (49.5%) exhibited spirometry findings below the lower limit of normal (LLN). In-depth pulmonary assessment for 61 participants revealed abnormalities in total lung capacity (31.6%<80% predicted), DLCO (53.4%<80% predicted), and chest-CT (86.7% abnormal). Significant risk factors for individual abnormal outcomes, adjusted for age and sex, were TB disease, HIV with CD4 <200cells/mm3, BMI <18.5kg/m2 and >35kg/m2, and initial COVID-19 severity. This study demonstrates substantial lung and functional morbidity within the first weeks post-COVID-19, particularly in individuals with pre-existing comorbidities including TB, HIV, and low or high BMI. Chest-CT and DLCO show best early potential at reflecting COVID-19-related pathologies. The Bavarian State Ministry of Science and Arts.

32. Comparative Genetic Architectures of Schizophrenia in Admixed African American and European Populations

32. Comparative Genetic Architectures of Schizophrenia in Admixed African American and European Populations

Multi-omic Analysis of Uterine Leiomyomas in Self-Described Black and White Women: Molecular Insights into Health Disparities

Black women are at an increased risk to develop uterine leiomyomas (ULMs) and to experience worse disease prognosis compared to White women. Epidemiological and molecular factors have been identified as underlying these disparities, but there remains a paucity of deep, multi-omic analysis investigating molecular differences in ULMs from Black and White patients. To identify molecular alterations within ULM tissues correlating with patient race by multi-omic analyses of ULMs collected from cohorts of Black and White women. We performed multi-omic analysis of ULMs from Black (42) and White (47) women undergoing hysterectomy for symptomatic uterine leiomyomata. Our analysis also included application of orthogonal methods to evaluate fibroid biomechanical properties, such as second harmonic generation microscopy, uniaxial compression testing, as well as sheer wave ultrasonography analyses. We found a greater proportion of mediator complex subunit 12 (MED12) mutant ULMs from Black women (>35% increase, Mann Whitney U p = 7E-4). MED12 mutant tumors exhibited elevated abundance of extracellular matrix proteins, including several collagen isoforms, involved in regulation of the core matrisome. Histological analysis of tissue fibrosis using trichrome staining and secondary harmonic generation microscopy confirmed that MED12 mutant tumors are more fibrotic than MED12 wildtype tumors. Using Sheer Wave ultrasonography in a prospectively collected cohort, Black patients had fibroids that were firmer when compared to White patients, even when similar in size. These analyses also uncovered expression quantitative trait loci (eQTL) associated with altered allele frequencies in African and European populations that correlated with differential abundance of several proteins in ULM that are independent of MED12 mutational status, including multiple eQTL mapping to tetratricopeptide repeat protein 38. Our study shows that Black women have a higher prevalence of ULMs harboring mutations in MED12 and that this mutational status correlates with increased tissue fibrosis in comparison with wildtype ULMs. Our study provides insights into molecular alterations underlying racial disparities in ULMs and improves our understanding of the molecular etiology underlying ULM development within these populations.

Prevalence of dry eye syndrome in a South African diabetic paediatric population

BackgroundDiabetes mellitus (DM) can be defined as a metabolic disorder that results from either the inability of insulin to perform its normal functions or decreased insulin secretion. Dry eye disease is a complex ailment of the tear film resulting in discomfort characterised by pain, a feeling of heavy eyes, grittiness, burning, dryness, itchiness, foreign body sensation, and visual disturbances. Patients with chronic conditions, i.e. DM, are more susceptible to developing dry eye due to various complications that may arise, such as, peripheral neuropathy, inflammatory alterations and reduced lacrimal gland function. AimTo identify the prevalence of dry eye syndrome in paediatric patients diagnosed with Diabetes Mellitus (Type 1/2). Method37 children with diabetes and 40 healthy, age group matched controls were enrolled in this study. Participants underwent a complete dry eye assessment in the following order: Ocular Surface Disease Index (OSDI) and McMonnies questionnaire, meibomian gland evaluation using white light, Tear Break-up Test (TBUT), Phenol Red Thread (PRT) test and Tear film Osmolarity test. Duration of diabetes was used as the parameter. ResultsThe incidence of dry eye syndrome was found to be higher among diabetics, with 15 (40.5 %) from the diabetic population compared to 4 (10.0 %) from the control group. TBUT and PRT test values were significantly reduced in children with diabetes (p < 0.001). TFO values were higher in the diabetics. No statistically significant differences were found the questionnaire scores, of the two groups, however the diabetic group appeared to be less symptomatic. ConclusionDry eye is more common in the diabetic paediatric population. TBUT and PRT results were found to be lower in diabetics. Results showed a strong correlation between duration of diabetes and TBUT values. Healthcare practitioners, working with children diagnosed with diabetes, should raise awareness as well as encourage early dry eye screening and intervention. Clinical significanceDue to the steady increase in the number of children and adolescents with diabetes, the characteristics and prevalence of dry eye syndrome in this population has become more valuable.

CRY2 (rs11605924) and G6PC2 (rs560887) single nucleotide polymorphisms increase the risk of type 2 diabetes mellitus in a mixed ancestry South African population

CRY2 (rs11605924) and G6PC2 (rs560887) single nucleotide polymorphisms increase the risk of type 2 diabetes mellitus in a mixed ancestry South African population

Causes of Past African Temperature Change in PMIP Simulations of the Mid‐Holocene

AbstractCurrent‐generation climate models project that Africa will warm by up to 5°C in the coming century, severely stressing African populations. Past and ongoing work indicates, however, that the models used to create these projections do not match proxy records of past temperature in Africa during the mid‐Holocene (MH), raising concerns that their future projections may house large uncertainties. Rather than reproducing proxy‐based reconstructions of MH warming relative to the Pre‐Industrial (PI), models instead simulate MH temperatures very similar to or slightly colder than the PI. This data‐model mismatch could be due to a variety of factors, including biases in model surface energy budgets or inaccurate representation of the feedbacks between temperature and hydrologic change during the “Green Sahara.” We focus on the differences among model simulations in the Paleoclimate Modeling Intercomparison Project Phases 3 and 4 (PMIP3 and PMIP4), examining surface temperature and energy budgets to investigate controls on temperature and the potential model sources of this paleoclimate data‐model mismatch. Our results suggest that colder conditions simulated by PMIP3 and PMIP4 models during the MH are in large part due to the joint impacts of feedback uncertainties in response to increased precipitation, a strengthened West African Monsoon (WAM) in the Sahel, and the Green Sahara. We extend these insights into suggestions for model physics and boundary condition changes, and discuss implications for the accuracy of future climate model projections over Africa.

Association between RS7903146, RS17817499, RS17782313, RS229616, RS1297034, RS699 and RS4646994 and cardiometabolic diseases in a black South African population

Association between RS7903146, RS17817499, RS17782313, RS229616, RS1297034, RS699 and RS4646994 and cardiometabolic diseases in a black South African population