Identifying the genetic causes of developmental disorders and intellectual disability in Africa: a systematic literature review.

Objective: Genetic variants cause a significant portion of developmental disorders and intellectual disabilities (DD/ID), but clinical and genetic heterogeneity makes identification challenging. Compounding the issue is a lack of ethnic diversity in studies into the genetic aetiology of DD/ID, with a dearth of data from Africa. This systematic review aimed to comprehensively describe the current knowledge from the African continent on this topic. Method: Applicable literature published up until July 2021 was retrieved from PubMed, Scopus and Web of Science databases, following PRISMA guidelines, focusing on original research reports on DD/ID where African patients were the focus of the study. The quality of the dataset was assessed using appraisal tools from the Joanna Briggs Institute, whereafter metadata was extracted for analysis. Results: A total of 3,803 publications were extracted and screened. After duplicate removal, title, abstract and full paper screening, 287 publications were deemed appropriate for inclusion. Of the papers analysed, a large disparity was seen between work emanating from North Africa compared to sub-Saharan Africa, with North Africa dominating the publications. Representation of African scientists on publications was poorly balanced, with most research being led by international researchers. There are very few systematic cohort studies, particularly using newer technologies, such as chromosomal microarray and next-generation sequencing. Most of the reports on new technology data were generated outside Africa. Conclusion: This review highlights how the molecular epidemiology of DD/ID in Africa is hampered by significant knowledge gaps. Efforts are needed to produce systematically obtained high quality data that can be used to inform appropriate strategies to implement genomic medicine for DD/ID on the African continent, and to successfully bridge healthcare inequalities.

Maternal Education Potentially Moderates the MAOA uVNTR Effects on Externalizing Behavior in Black South African Children.

Interactions between the MAOA uVNTR and rearing environment are suggested to influence the developmental manifestations of childhood internalizing and externalizing behavior. However, few studies in the MAOA literature have included continental African children, or focused on non-clinical samples. We explored the main and interactive effects of the MAOA uVNTR (high and low activity alleles) in Black South African male (n = 478) and female (n = 540) children who were part of the longitudinal Birth to Twenty Plus cohort. Historical data on birth weight, gestational age at delivery, socioeconomic status, and maternal education were combined with genotypic information and analyzed using regression modeling. We found no significant main effects for the MAOA uVNTR on childhood behavior in either sex. A significant interaction (p = .04) was identified between MAOA and maternal education, suggesting that externalizing behavior in boys carrying a low activity MAOA allele varied in direct proportion to the education levels of their mothers. However, the model fit failed to reach significance, possibly due to our inclusion of only non-clinical pre-pubertal males. No significant interactions were detected for female children. Our findings lend tentative credibility to the Environmental Sensitivity metaframework, which suggests that MAOA is an important plasticity factor in childhood development.

Reliability and validity of last menstrual period for gestational age estimation in a low-to-middle-income setting.

AIM: Gestational age estimation by ultrasonography is the gold standard for dating pregnancies. However, the availability of prenatal ultrasonography in low-to-middle-income countries is limited. This study aimed to assess the reliability and validity of last menstrual period (LMP) as a gestational age dating method among women in Johannesburg, South Africa. METHODS: A total of 741 pregnant women were enrolled into a longitudinal study (June 2013 to July 2016). Gestational age was determined by LMP and ultrasonography. Differences in ultrasound-based and LMP-based gestational age estimates were assessed according to the American College of Obstetrics and Gynecologists' guidelines and women were classified as having discrepant results or not. Multiple statistical analyses determined the level of agreement between the two methods and validity of LMP estimates. RESULTS: Compared to ultrasound, dating by LMP assessed gestational age as 0.2 days longer. Women with discrepant results were of significantly lower weight and household socioeconomic status than those without discrepancies. While there was a substantial agreement (k = 0.64; 95% confidence interval, CI: 0.54, 0.71, P < 0.001) between the two methods, LMP only had a 29.0% (95% CI: 14.2, 48.0) sensitivity in identifying late-term neonates and a 33.3% (95% CI: 4.33, 77.7) sensitivity in identifying post-term neonates. CONCLUSION: In the absence of ultrasound, LMP is a reliable alternative for gestational age dating during early pregnancy. However, it is not sensitive in identifying late- and post-term pregnancies and should not be relied upon to make clinical decisions regarding elective cesarean section or induction of labor for supposed prolonged pregnancies.

The Global State of the Genetic Counseling Profession.

The profession of genetic counseling (also called genetic counselling in many countries) began nearly 50 years ago in the United States, and has grown internationally in the past 30 years. While there have been many papers describing the profession of genetic counseling in individual countries or regions, data remains incomplete and has been published in diverse journals with limited access. As a result of the 2016 Transnational Alliance of Genetic Counseling (TAGC) conference in Barcelona, Spain, and the 2017 World Congress of Genetic Counselling in the UK, we endeavor to describe as fully as possible the global state of genetic counseling as a profession. We estimate that in 2018 there are nearly 7000 genetic counselors with the profession established or developing in no less than 28 countries.

The prevalence of gestational diabetes mellitus amongst black South African women is a public health concern.

AIMS: This study aimed to determine the prevalence of gestational diabetes mellitus (GDM) amongst black South African women, describe GDM-associated risk factors and clinical management, and evaluate the efficacy of the fasting plasma glucose reading in diagnosing GDM. METHODS: A cross-sectional screening study was performed. Pregnant women were recruited from the Chris Hani Baragwanath Academic Hospital in Johannesburg. A total of 1906 women underwent a two-hour 75 g oral glucose tolerance test at 24-28 weeks gestation. The World Health Organization's 2013 criteria were used to diagnose GDM. RESULTS: A total of 174/1906 (9.1% (95% confidence interval (CI) 7.9, 10.5)) women were diagnosed with GDM. These women had significantly higher weights and body mass indexes (BMIs), were significantly older, of higher household socioeconomic status, more likely to report a family history of diabetes, and more likely to be diagnosed with anaemia than women without GDM. An age of ≥35 years, BMI ≥ 30 kg/m2, and a family history of diabetes were significant risk factors. The fasting plasma glucose reading had a high sensitivity (83.3% (95% CI 77.0, 88.5)) in diagnosing GDM and 56.9% of the women with GDM were managed by diet therapy alone. CONCLUSION: This is the largest GDM prevalence study in South Africa to date. A diagnosis of GDM increases the risk of both mother and child developing Type 2 diabetes which causes further health complications, decreases longevity, and burdens a country's healthcare system. Therefore, a GDM prevalence of 9.1% is concerning and warrants further discussion around current GDM screening policies.

Genetic counseling globally: Where are we now?

The genetic counseling profession is continuing to develop globally, with countries in various stages of development. In some, the profession has been in existence for decades and is increasingly recognized as an important provider of allied health, while in others it is just beginning. In this article, we describe the current global landscape of the genetic counseling specialty field's professional development. Using examples of the United States, United Kingdom, Canada, Australia, South Africa, and various countries in Asia, we highlight the following: (a) status of genetic counseling training programs, (b) availability of credentialing through government and professional bodies (certification, registration, and licensure), and potential for international reciprocity, (c) scope of clinical practice, and (d) health-care system disparities and cultural differences impacting on practice. The successful global implementation of precision medicine will require both an increased awareness of the importance of the profession of "genetic counselor" and flexibility in how genetic counselors are incorporated into each country's health-care market. In turn, this will require more collaboration within and across nations, along with continuing engagement of existing genetic counseling professional societies.

The first two confirmed sub-Saharan African families with germline TP53 mutations causing Li-Fraumeni syndrome.

Li-Fraumeni syndrome is a rare inherited cancer syndrome characterised by the early onset of specific cancers. Li-Fraumeni syndrome (LFS) is associated with germline mutations in the tumour suppressor gene, TP53. This study reports the first cases of molecularly confirmed LFS germline mutations in sub-Saharan Africa. Three black African patients, all with LFS-associated cancers, were seen through the Clinical and Counselling Section of the Division of Human Genetics at the National Health Laboratory Service and University of the Witwatersrand in Johannesburg, South Africa, during 2011-2012. All three patients (two were related) were recruited into this research study. Sequence analysis of the coding region of the TP53 gene identified a Class IV (likely pathogenic) variant, c.326T > C (p.Phe109Ser), in the two related patients, and a known pathogenic mutation, c.1010G > A (p.Arg337His), also referred to as the Brazilian founder mutation, in the other patient. A confirmed diagnosis in these patients will assist in tailored medical management (it is recommended that individuals carrying a germline TP53 mutation avoid radiotherapy as this might cause secondary radiotherapy-induced malignancies) and in addition, genetic testing of at-risk family members can be offered. Very little is known and documented on LFS in African individuals. Despite the small number of patients in this study, the results support the need for diagnostic genetic testing for LFS in South Africa.

The effect of lifestyle interventions on maternal body composition during pregnancy in developing countries: a systematic review.

Optimal maternal body composition during pregnancy is a public health priority due to its implications on maternal health and infant development. We therefore aimed to conduct a systematic review of randomised, controlled trials, and case-control and cohort studies using lifestyle interventions to improve body composition in developing countries. Of the 1 708 articles that were searched, seven studies, representing three countries (Brazil, Iran and Argentina), were included in the review. Two articles suggested that intervention with physical activity during pregnancy may significantly reduce maternal weight gain, and five studies were scored as being of poor quality. This systematic review highlights the lack of research within developing countries on lifestyle interventions for the management of excessive weight gain during pregnancy. Similar reviews from developed countries demonstrate the efficacy of such interventions, which should be confirmed using well-designed studies with appropriate intervention methods in resource-limited environments.

Physical activity and the risk for gestational diabetes mellitus amongst pregnant women living in Soweto: a study protocol.

BACKGROUND: Over the past decade the prevalence of gestational diabetes mellitus (GDM) has increased rapidly in both developed and developing countries and has become a growing health concern worldwide. A recent systematic review highlighted the paucity of data available on the prevalence and potential burden of GDM in Africa, which was emphasised by the fact that only 11 % of African countries were represented in the review. In South Africa, the prevalence of GDM remains unknown, although one would estimate it to be high due to urbanisation and the growing obesity epidemic. In addition, the association between physical activity (PA), sedentary behaviour (SB) and GDM is not well understood in this population. The aim of the proposed research is to determine whether there is an association between physical activity, sedentary behaviour and risk for GDM in pregnant black women living in urban Soweto in South Africa. METHODS/DESIGN: This prospective cohort study of 80 participants will include pregnant women from Soweto enrolled into the Soweto First 1000 Days Study (S1000) at the MRC/Wits Departmental Pathways for Health Research Unit (DPHRU) based at the Chris Hani Baragwanath Academic Hospital in Soweto, South Africa. Women will be enrolled into the S1000 Study at <14 weeks gestation, and baseline demographic and anthropometric measures will be taken at 14-18 weeks gestation (visit 1). In addition, participants will complete the Global Physical Activity Questionnaire (GPAQ) to measure self-reported physical activity and will be given an ActiGraph accelerometer to wear for seven days to measure habitual physical activity at 14-18 weeks gestation (visit 1), and at 28-33 weeks gestation (visit 3). At visit 2 (24-28 weeks gestation) an oral glucose tolerance test (OGTT) will be conducted. DISCUSSION: Physical activity during pregnancy has been associated with minimum risk to a pregnancy and may play a role in improving glucose metabolism and therefore decreasing risk for GDM. This is particularly pertinent to assess amongst black South African women who are a potentially high risk population due to the high prevalence of obesity and type 2 diabetes (T2D). The findings of the study will assist in developing targeted interventions as well as feasible healthcare strategies.

Breast cancer in high-risk Afrikaner families: Is BRCA founder mutation testing sufficient?

BACKGROUND: Germline pathogenic mutations in cancer susceptibility genes result in inherited cancer syndromes. In the Afrikaner population of South Africa (SA), three founder mutations in the BRCA genes that lead to hereditary breast and ovarian cancer syndrome (HBOCS) have been identified. OBJECTIVES: To investigate the uptake and type of molecular testing performed on patients for HBOCS, to determine the prevalence of the three Afrikaner founder BRCA mutations as well as non-founder BRCA mutations in the study population, and to analyse the utility of two mutation prediction models (Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) and Manchester scoring method) in assisting with the decision for the most cost-effective testing option. METHODS: A retrospective file review was performed on counsellees of self-reported Afrikaner ancestry from Johannesburg, SA (2001 - 2014), with a personal or family history of breast and/or ovarian cancer. Demographic and family history information was recorded and Manchester and BOADICEA scores were calculated for each patient. RESULTS: Of 86 unrelated counsellees whose files were reviewed, 54 (62.8%) underwent BRCA genetic testing; 18 (33.3%) tested positive for a mutation, and 14 of these (77.8%) for an Afrikaner founder mutation. Twelve counsellees had the BRCA2 c.7934delG mutation. Four non-founder mutations were identified. BOADICEA scores were significantly higher in counsellees who tested positive for a mutation than in those who tested negative. CONCLUSIONS: Founder mutation testing should be performed as a first-line option. BOADICEA is very useful in identifying counsellees at high risk for a BRCA mutation and also assists with the decision to pursue further testing following a negative founder mutation result. These findings assist in guiding an informed genetic counselling service for at-risk individuals with an Afrikaner background.

Gestational diabetes mellitus in Africa: a systematic review.

BACKGROUND: Gestational diabetes mellitus (GDM) is any degree of impaired glucose tolerance first recognised during pregnancy. Most women with GDM revert to normal glucose metabolism after delivery of their babies; however, they are at risk of developing type 2 diabetes later in life as are their offspring. Determining a country's GDM prevalence can assist with policy guidelines regarding GDM screening and management, and can highlight areas requiring research. This systematic review assesses GDM prevalence in Africa. METHODS AND FINDINGS: Three electronic databases were searched without language restrictions; PubMed, Scopus and the Cochrane Library. Thirty-one search terms were searched. Eligible articles defined GDM, stated what GDM screening approaches were employed and reported GDM prevalence. The reporting quality and risk of bias within each study was assessed. The PRISMA guidelines for systematic reviews were followed. The literature search identified 466 unique records. Sixty full text articles were reviewed of which 14 were included in the systematic review. One abstract, for which the full text article could not be obtained, was also included. Information regarding GDM classification, screening methods and prevalence was obtained for six African countries; Ethiopia (n = 1), Morocco (n = 1), Mozambique (n = 1), Nigeria (n = 6), South Africa (n= 4) and Tanzania (n = 1). Prevalence figures ranged from 0% (Tanzania) to 13.9% (Nigeria) with some studies focussing on women with GDM risk factors. Most studies utilised the two hour 75 g oral glucose tolerance test and applied the World Health Organization's diagnostic criteria. CONCLUSIONS: Six countries, equating to 11% of the African continent, were represented in this systematic review. This indicates how little is known about GDM in Africa and highlights the need for further research. Considering the increasing public health burden of obesity and type 2 diabetes, it is essential that the extent of GDM is understood in Africa to allow for effective intervention programmes.

Uptake of Genetic Counselling Services by Patients with Cystic Fibrosis and Their Families

Background: Although cystic fibrosis (CF) is a common genetic condition; genetic counselling services appear to be underutilised by affected families. The aim of this study was to determine the uptake of genetic counselling and mutation testing for CF by relatives of affected individuals; and the impact of introducing hospital-based genetic counselling services.Method: The files of 153 families seen for genetic counselling for CF by staff of the Division of Human Genetics; School of Pathology; University of the Witwatersrand; and the National Health Laboratory Service (NHLS) in Johannesburg; were retrospectively reviewed from 1990 to 2006; the year when hospital-based genetic counselling services were introduced.Results: Parents of CF probands were the largest single group (35) of counsellees. Most individuals (66) attended genetic counselling to gather information. Most had been referred by medical specialists (56). Only 10 of referrals originated from general practitioners. On average; from 1990-2005; six families received genetic counselling annually; whereas in 2006; 58 families were seen. In 140 unrelated families; 1 991 relatives with carrier risks of ? 25 were identified. Only 11of these relatives underwent mutation testing; and eight per cent received genetic counselling through our division over the review period.Conclusion: Overall; referrals of family members (of affected CF individuals) to genetic counselling; by general practitioners; are poor. Uptake of genetic counselling services is greater when such services are integrated into hospital-based CF management clinics; than when offered elsewhere. The low uptake of mutation testing and genetic counselling by at-risk relatives is a concern; since these relatives are at high risk of having affected children; if their partners are CF carriers. Education of affected individuals; their close relatives; and medical practitioners; should be prioritised. This will ensure referral to genetic counselling for discussion about the risks of and available testing for CF; and other genetic conditions