The impact of motherless paternity testing in a South African population

BackgroundPaternity investigations play an important role in determining biological relatedness, and in South Africa, the outcome of these investigations impacts medical, judicial and home affairs decisions. Short Tandem Repeat (STR) analysis is utilised to perform paternity and kinship analysis, due to the polymorphic nature of STR loci. The cost associated with paternity testing is high, and there is a demand for motherless testing.ObjectivesThis study aims to determine what the impact of motherless testing would have been by evaluating 6182 paternity trio cases.MethodsThe AmpFLSTR™ Identifiler™ PCR Amplification kit was used to profile each of the trio cases. A scenario was created where the mother was eliminated from the test results to determine if the paternity outcome would change.ResultsPutative fathers were excluded in 27% of all cases, and in 2.5% of those cases, putative fathers would have been falsely included, had the mother not been tested. These false inclusions are attributed to coincidental STR loci that are shared between the mother and the putative father. The addition of loci to the STR profiling kit may resolve the issue; however, comparable STR data with more loci will have to be evaluated to ensure it overcomes the issue of coincidentally shared loci between unrelated individuals.ConclusionWe would recommend that within our setup and within similar setups, the mother always be included for testing, except in extreme scenarios such as death. False inclusion of putative fathers could have serious legal implications for testing laboratories.     

Healthcare experiences of patients with Down syndrome who are Black,African American,of African descent,or of mixed race

Scant research has explored the healthcare experiences of people with Down syndrome (DS) in the United States who are Black, African American, of African descent, or of mixed race. The purpose of this study was to identify and describe the barriers and facilitators that such patients and their caregivers face when accessing healthcare. We gathered data in three ways: focus groups with caregivers, a national survey completed by caregivers, and in-depth interviews with primary care providers. Many caregivers and primary care physicians felt that patients with DS who are Black, African American, of African descent, or of mixed race receive a lower quality of medical care than their white counterparts with DS. Caregivers mentioned feeling tired of being reminded by the medical community about their race and wanting acknowledgment that raising a child with DS can be hard at times. Many felt that the medical community's conscious and unconscious racial biases do negatively impact the care of their loved ones with DS. Caregivers desired more race concordant medical providers or, when not possible, medical providers who are willing to learn more about DS and build trusted, longitudinal relationships. Primary care providers discussed the need for funded resources and support services to effectively care for their patients with DS.     

The emerging role of ACE2 in physiology and disease

The renin-angiotensin-aldosterone system (RAAS) is a key regulator of systemic blood pressure and renal function and a key player in renal and cardiovascular disease. However, its (patho)physiological roles and its architecture are more complex than initially anticipated. Novel RAAS components that may add to our understanding have been discovered in recent years. In particular, the human homologue of ACE (ACE2) has added a higher level of complexity to the RAAS. In a short period of time, ACE2 has been cloned, purified, knocked-out, knocked-in; inhibitors have been developed; its 3D structure determined; and new functions have been identified. ACE2 is now implicated in cardiovascular and renal (patho)physiology, diabetes, pregnancy, lung disease and, remarkably, ACE2 serves as a receptor for SARS and NL63 coronaviruses. This review covers available information on the genetic, structural and functional properties of ACE2. Its role in a variety of (patho)physiological conditions and therapeutic options of modulation are discussed.     

Killer-cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) class I genetic diversity in four South African populations

Killer-cell Immunoglobulin-like Receptor (KIR) and Human Leukocyte Antigen (HLA) genotypes vary considerably between individuals and populations due to KIR/HLA allelic variation and variable haplotype configurations of KIR. HLA mediate natural killer cell activity by serving as KIR ligands. KIR/HLA polymorphisms associate with both disease susceptibility and severity. We determined the frequencies of KIR, KIR genotypes and KIR-HLA combinations in 364 healthy individuals from four South African populations. Study participants included black African (n = 167), Caucasian (n = 97), Mixed ancestry (n = 50) and Indian (n = 50) individuals. We identified 48 KIR genotypes that included two genotypes not previously reported. Based on KIR gene content, Indian individuals represented the most distinct group, showing the highest frequencies of KIR2DL2, KIR2DL5, KIR2DS1, KIR2DS2, KIR2DS3 and KIR3DS1, the lowest frequencies of KIR2DL3, KIR2DS4 and KIR3DL1; and a KIR2DL4-negative individual. KIR2DS1 and KIR3DS1 were infrequent in black African populations. HLA-C2 was more common in black African individuals, while HLA-C1 predominated in the other populations. Indian individuals were more likely to possess KIR2DL2 paired with HLA-C1, while Caucasian individuals exhibited the highest frequencies of KIR2DL3 paired with HLA-C1. This report provides comprehensive reference data for further study of the roles of KIR/HLA in non-communicable and infectious diseases in South African populations.     

The Impact of HLA-G 3′UTR Polymorphisms in Breast Cancer in a Tunisian Population

Human leukocyte antigens G and E (HLA-G and HLA-E) are nonclassical major histocompatibility complex (MHC) class I molecules. These molecules play an important role in immune surveillance by inhibiting natural killer and cytotoxic T cells responsible for immune escape. The expression of HLA-G and HLA-E has been associated with several diseases including tumor. The main objective of the study is to evaluate the impact of three HLA-G 3?UTR potential polymorphisms: +3187 A > G (rs9380142), +3142 G > C (rs1063320), +2960 14-base pair (bp) Insertion/Deletion (Ins/Del) (rs66554220), and the HLA-E*01:01/01:03 A > G (rs1264457) polymorphism in Tunisian breast cancer population. A total of 355 patients and 381 controls were genotyping for HLA-G and HLA-E polymorphisms using a Taq Man assay. +3142 C allele and +3142 C/C genotype were significantly associated with increased risk of breast cancer (p = 0.00002; OR = 1.58; 95% CI = 27–1.97) (49% versus 35%; p = 0.0001; OR = 1.79; 95% CI = 1.32–2.44). In addition, Del allele and the homozygous state for Del/Del genotype confer a risk for breast cancer (52% versus 45%, p = 0.006; OR = 1.33, 95% CI = 1.08–1.64) (28% versus 22%, p = 0.039; OR = 1.43, 95% CI = 0.90–2.25). However, no statistical significant differences were reported for HLA-G + 3187 A > G and HLA-E variations and breast cancer in a Tunisian population.

The found results indicate that HLA-G may play an important role in the breast cancer.     

Appositional enamel growth in molars of South African fossil hominids

Enamel is formed incrementally by the secretory activity of ameloblast cells. Variable stages of secretion result in the formation of structures known as cross striations along enamel prisms, for which experimental data demonstrate a correspondence with daily periods of secretion. Patterns of variation in this daily growth are important to understanding mechanisms of tooth formation and the development of enamel thickness. Transmitted light microscopy (TLM) of histological ground sections and scanning electron microscopy (SEM) of bulk specimens or their surface replicas are the usual methods for investigating cross striations. However, these methods pose some constraints on the study of these features in Plio-Pleistocene hominid enamel, the specimens of which may only rarely be sectioned for TLM or examined on only their most superficial surfaces for SEM. The recent development of portable confocal scanning optical microscopy (PCSOM) resolves some of the restrictions on fractured enamel surfaces, allowing the visualization of cross striations by direct examination. This technology has been applied here to the study of Australopithecus africanus and Paranthropus robustus hominid molars from the Plio-Pleistocene of South Africa. We hypothesize that these taxa have increased enamel appositional rates compared with modern humans, because despite having thicker enamelled molars (particularly P. robustus), the enamel crowns of these fossil taxa take an equivalent or reduced amount of time to form. Cross striations were measured in cuspal, lateral and cervical regions of the enamel crowns, and, within each region, the inner, middle and outer zones. Values obtained for A. africanus outer zones of the enamel crown are, in general, lower than those for P. robustus, indicating faster forming enamel in the latter, while both taxa show higher rates of enamel growth than modern humans and the African great apes. This demonstrates a relatively high degree of variability in the mechanisms underlying the development of enamel across taxa.     

Polymorphism of the ACE Gene in dialysis patients: overexpression of DD genotype in type 2 diabetic end-stage renal failure patients

The angiotensin-converting enzyme (ACE) gene DD homozygote has been suggested to be a significant risk factor for the progression of diabetic nephropathy. We analyzed clinical parameters and ACE genotype distribution between type 2 diabetic patients at the extremes of renal risk, i.e. an end-stage renal failure (ESRF) group (n = 103, group 1) who were on dialysis therapy due to progression of diabetic nephropathy, and a no progression group (n = 88, group 2) who had maintained normal renal function and normoalbuminuria for more than 15 years. There were no significant differences in age, sex, body mass index, HbA1c level, or lipid profiles between the two groups (p > 0.05). Group 1 had a significantly higher prevalence of hypertension [group 1: 82.5% (85/103) vs. group 2: 50.0% (44/88), p < 0.05] and diabetic retinopathy [group 1: 103/103 (100%) vs. group 2: 28/88 (31.8%), p < 0.05] than group 2. Daily urinary albumin excretion was also higher in group 1 than in group 2 [group 1: 2873 +/- 2176 mg/day vs. 12 +/- 7 g/day, p < 0.05]. The frequencies of the DD, ID, and II genotypes of the ACE gene in group 1 and group 2 were 26.2%, 47.6%, and 26.2%, and 7.9%, 57.9%, and 34.2%, respectively. The ACE genotype frequencies between the two groups were significantly different according to a chi-square test with Bonferroni's correction (p = 0.004). The presence of the DD genotype increased the risk of ESRF 4.286-fold compared to the II genotype [odds ratio 4.286, 95% CI 1.60- 11.42, p = 0.005]. The frequency of the D-allele was higher in both male and female patients in group 1 compared to group 2, but reached statistical significance only in males [male, group 1: 50.8% vs. group 2: 35.0%, p = 0.018, female, group 1: 48.8% vs. group 2: 39.5%, p = 0.231]. This study, although limited by sample size, showed that type 2 diabetic ESRF patients more frequently expressed the DD genotype. These findings may substantiate the previously noted relationship between the ACE DD genotype and the progression of diabetic nephropathy in Korean type 2 diabetic patients.     

ACE Genotype May Have an Effect on Single versus Multiple Set Preferences in Strength Training

A polymorphic variant of the human angiotensin converting enzyme (ACE) gene was identified. The 'D' (rather than 'I') variant was associated with improvements in strength related to physical training. We set out to determine whether the response to different patterns of strength training might also differ. Ninty-nine Caucasian male non-elite athletes were randomly allocated into one of three groups: 31 non-training/control (CG: 31), single-set (SSG: 35) and multiple-set (MSG: 33). SSG and MSG trained three times a week for 6 weeks. Both training groups were underwent a strength-training program with two mesocycles (12-15 repetition maximum (RM) and 8-12 RM mesocycles). One RM loads in half squat and bench press were assessed before training and after the first and second mesocycles. ACE polymorphisms analysed by polymerase chain reaction (PCR) methods. Subjects with ACE II genotype in the MST group had improved strength development in 12-15 RM, while SST and MST groups had similar gains in 8-12 RM. Subjects with ACE DD genotype in both the SSG and the MSG had similar benefits from both 12-15 RM and 8-12 RM. Strength gains for subjects with ACE ID genotype in the SSG were similar to MSG gains in response to 8-12 RM loads but not with 12-15 RM loads. Additionally, subjects with DD genotype had superior strength gains in both strength training groups. Tailoring strength training programmes (single-set vs. multiple set) according to the athlete's ACE genotype may be advantageous.     

Disease progression, response to ACEI/ATRA therapy and influence of ACE gene in IgA nephritis

Various studies have shown that angiotensin-converting enzyme （ACE） gene insertion/deletion （ID） polymorphism may play a role in the progression to end stage renal failure （ESRF） in patients with IgA nephritis （IgAN）. In this randomized controlled trial, patients were followed up for 5 years to determine their long-term renal outcome to ACEI/ATRA therapy and to ascertain if their ACE gene profile could play a role in determining their response to therapy. Seventy-five patients with IgAN were enlisted. Thirty-seven were on ACEI/ATRA therapy for 62 ± 5 months and thirty-eight were untreated and served as controls. All patients had their ACE gene ID polymorphism genotyped. Compared to controls, treated patients had lower serum creatinine （p 〈 0.001）, lower proteinuria （p 〈 0.002） and fewer numbers progressing to ESRF （p 〈 0.002）. Among patients with genotype II, there were less ESRF in the treatment group when compared to the untreated control group （p 〈 0.02）. The advantage of therapy was not seen in patients with ID or DD genotypes. ACEI/ATRA therapy was found to be effective in retarding disease progression in IgAN with years to ESRF significantly extended in patients at all levels of renal function, including patients whose outcome were ESRF. Genotyping showed better response to therapy only for those with genotype Ⅱ. The common mechanism is probably through lower levels of ACE, glomerular pressure and proteinuria resulting in reduced renal damage and retardation of progression to ESRF. Cellular ＆ Molecular Immunology.     

Maternal non-recognition of Down syndrome in black South African infants

Down syndrome (DS), one of the commonest causes of mental retardation in Caucasoids, has only rarely been described in Africa. In previous studies it was suggested that there may be clinical difficulties in making the diagnosis in African neonates. In the present study data were collected by means of a questionnaire administered partly before and partly after a genetic counselling session, to 35 mothers of African infants with DS. The results show that 83% of these mothers did not recognise any facial difference between their affected infant and other normal infants and 57% did not observe any other physical differences. After counselling, 40% of the sample still did not accept that their infant was different from other newborns. Only one mother was aware of infants with similar characteristics. These findings suggest that if mothers themselves cannot see the differences between their DS children and normal children, clinical diagnosis based on physical stigmata may be difficult. Furthermore, acceptance of the diagnosis may be retarded until delayed milestones can be observed in the affected infants.     

Apolipoprotein E allele frequencies in a South African Indian female population

Coronary heart disease is common amongst South Africans of Indian (Asian) ancestry. As part of an investigation into risk factors in premenopausal and post-menopausal Indian nurses, we determined the apolipoprotein E genotype by means of restriction isotyping on 173 healthy nurses between the ages of 25–55 years. The apolipoprotein E allele frequencies on 346 chromosomes were: ε2, 1.2% (95% confidence interval 0.06-2.66); ε3, 87.6% (95% confidence interval 84.1–91.1 and ε4, 11.3% (95% confidence interval 7.94-14.60). No ε2/2 homozygotes were encountered. Our results demonstrate an extremely low frequency of the ε2 allele, a low-normal apo ε4 and a high ε3 allele frequency. It is unlikely that apolipoprotein E polymorphism contributes to the high incidence of coronary heart disease in this population.     

Elucidation of CYP2D6 Genetic Diversity in a Unique African Population: Implications for the Future Application of Pharmacogenetics in the Xhosa Population

Genetic variation of the CYP2D6 gene has been associated with altered drug metabolism; however, limited studies have investigated CYP2D6 sequence diversity in African populations. We devised a CYP2D6 genotyping strategy to analyse the South African Xhosa population and genotype a Xhosa schizophrenia cohort, as CYP2D6 metabolises many antipsychotics and antidepressants. The entire CYP2D6 gene locus was sequenced in 15 Xhosa control individuals and the data generated were used to design a comprehensive genotyping strategy. Over 25 CYP2D6 alleles were genotyped in Xhosa controls and Xhosa schizophrenia patients using long‐range PCR, DNA sequencing and single nucleotide primer extension analysis. Bioinformatic algorithms were used to predict the functional consequences of relevant mutations and samples were assigned CYP2D6 activity scores. A unique allele distribution was revealed and two rare novel alleles, CYP2D6*73 and CYP2D6*74, were identified. No significant differences in allele frequencies were detected between Xhosa controls and schizophrenia patients. This study provides i) comprehensive data on a poorly characterised population, ii) a valuable CYP2D6 genotyping strategy and iii) due to their unique genetic profile, provides the basis for pharmacogenetic intervention for Xhosa individuals.     

Internet and Mobile Technology Use Among Urban African American Parents: Survey Study of a Clinical Population

Background

There is considerable potential for mobile technologies to empower pediatric patients and families by improving their communication with health professionals. National surveys suggest minority parents frequently communicate via mobile technology, but it is uncertain how amenable they are to receiving health care information in this format. Although the low cost and far reach characteristics of mobile health (mHealth) technology makes it advantageous for communication with minority parents, data on acceptance are needed.

Objective

The objective of the study was to determine utilization of mobile and Internet technology by African American parents in an urban, underserved population, and to assess their interest in receiving health information via text messaging or other technologies (eg, social media and the Internet).

Methods

A survey was administered to parents of children aged 1-12 years covered by public insurance receiving care at 3 pediatric primary care centers in Washington, DC.

Results

The African American sample (N=302) was composed of primarily single (75.8%, 229/302) mothers. Almost half had more than a high school education (47.7%, 144/302) and incomes above US $25,000 per year (43.0%, 130/302). Most (97.0%, 293/302) reported owning a cell phone, of which 91.1% (275/302) used it to text and 78.5% (237/302) used it to access the Internet. Most had service plans with unlimited text and data, but 26.5% (80/302) experienced service interruptions in the previous year. Home Internet access was more prevalent among those with higher income (86.2%, 112/130), but it was still relatively pervasive among lower income families (66.9%, 83/124). In adjusted logistic regression models, African American mothers with income greater than US $25,000 annually were 4 times as likely to own a tablet computer than their lower income counterparts. Of the participants, 80.8% (244/302) used social networking, primarily Facebook, and 74.2% (224/302) were interested in joining a social networking group about a health topic concerning their child. Although relatively few African American mothers (17.9%, 54/302) shared health information via texting, there was strong interest in receiving health information via mobile phones (87.4%, 264/302). There was no significant difference in Internet/mobile device use or interest in using these outlets to send/receive information about their children’s health between parents of healthy children and parents of children with chronic health conditions.

Conclusions

Urban African American parents are active users of the Internet and mobile technology for social interactions, but they are less likely to use it for accessing or communicating health information. However, most parents expressed an interest in receiving health information or utilizing social networking to learn more about health topics. Mobile technology and social networks may be an underutilized method of providing health information to underserved minority populations.     

Human leukocyte antigen class I (A,B, C) and class II (DPB1, DQB1, DRB1) allele and haplotype variation in Black South African individuals

South Africa has a population of 58.78 million, of which 80.7% are Black African individuals, representing 9 predominant ethnic/linguistic groups (Zulu, Xhosa, Pedi, Tswana, South Sotho, Tsonga, Swati, Venda and Ndebele). HIV-1 and Mycobacterium tuberculosis infection are the leading causes of death (7.8% and 5.9%, respectively) in this population group. To provide reference HLA allele and haplotype data for studies of gene-associations with infectious/non-infectious diseases or vaccine development, we have updated previously published HLA class I (A, B, C) and class II DRB1 genotypes and determined high-resolution class II (DPB1, DQB1) genotypes for n = 142 healthy, unrelated Black South African individuals.     

Novel and established CYP2A6 alleles impair in vivo nicotine metabolism in a population of Black African descent

Cytochrome P450 2A6 (CYP2A6) is a human enzyme best known for metabolizing tobacco-related compounds, such as nicotine, cotinine (COT), and nitrosamine procarcinogens. CYP2A6 genetic variants have been associated with smoking status, cigarette consumption, and tobacco-related cancers. Our objective was to functionally characterize four nonsynonymous CYP2A6 sequence variants with respect to their haplotype, allele frequency, and association with in vivo CYP2A6 activity. In vivo, nicotine was administered orally to 281 volunteers of Black African descent. Blood samples were collected for kinetic phenotyping and CYP2A6 genotyping. In vitro, nicotine C-oxidation catalytic efficiencies of heterologously expressed variant enzymes were assessed. The four uncharacterized sequence variants were found in seven novel alleles CYP2A6(*)24A&B ; (*)25, (*)26, (*)27, and *28A&B, most were associated with impaired in vivo CYP2A6 activity. Nicotine metabolism groupings, based on the in vivo data of variant alleles, were created. Mean trans-3'-hydroxycotinine/cotinine (3HC/COT) differed (P<0.001) between normal (100%), intermediate (64%), and slow (40%) groups. Systemic exposure to nicotine following oral administration also differed (P<0.001) between normal (100%), intermediate (139%), and slow (162%) metabolism groups. In addition, alleles of individuals with unusual phenotype-genotype relationships were sequenced, resulting in the discovery of five novel uncharacterized alleles and at least one novel duplication allele. A total of 7% of this population of Black African descent had at least one of the eight novel characterized alleles and 29% had at least one previously established allele. These findings are important for increasing the accuracy of association studies between CYP2A6 genotype and behavioral, disease, or pharmacological phenotypes.     

Lack of association of angiotensin-converting enzyme (ACE). Gene insertion/deletion polymorphism with CAD in two Asian populations

Association of the insertion/deletion polymorphism of the angiotensin-converting enzyme ( ACE ) gene with coronary artery disease with or without myocardial infarction (MI) was examined in a group of Chinese and Indian men in Singapore. The sample comprised an angiographically confirmed patient group of 276 Chinese and 102 Indians, of which 155 Chinese and 72 Indians had MI, and a matched healthy control group (147 Chinese and 166 Indians). The frequency of the D allele in the Chinese was 0.39 in those with CAD with MI, 0.43 in those with CAD but without MI, and 0.41 in the control group. The frequency of the D allele in Indians was 0.44 in CAD with or without MI, and 0.45 in the control group. There was no significant association of the ACE gene with CAD or MI in the Chinese or Indians, either in the entire sample or in different risk groups. The frequency of the D allele was significantly lower in the healthy Chinese and Indians than that reported in Caucasians. The association of the ACE gene with MI or CAD observed in other studies could not be confirmed in the present series of Chinese and Indians in Singapore.     

Identification of critical determinants on ACE2 for SARS-CoV entry and development of a potent entry inhibitor

Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus, SARS-CoV. Virus entry into cells is mediated through interactions between spike (S) glycoprotein and angiotensin-converting enzyme 2 (ACE2). Alanine scanning mutagenesis analysis was performed to identify determinants on ACE2 critical for SARS-CoV infection. Results indicated that charged amino acids between residues 22 and 57 were important, K26 and D30, in particular. Peptides representing various regions of ACE2 critical for virus infection were chemically synthesized and evaluated for antiviral activity. Two peptides (a.a. 22-44 and 22-57) exhibited a modest antiviral activity with IC₅₀ of about 50 μM and 6 μM, respectively. One peptide comprised of two discontinuous segments of ACE2 (a.a. 22-44 and 351-357) artificially linked together by glycine, exhibited a potent antiviral activity with IC₅₀ of about 0.1 μM. This novel peptide is a promising candidate as a therapeutic agent against this deadly emerging pathogen.     

Human leukocyte antigen class I (A,B and C) allele and haplotype variation in a South African Indian population

In 2013, ～1,329,300 individuals made up the South African Indian population, which constituted ～2.5% of the total population of ～53 million. Historically, from 1860 to 1911, indentured labourers were imported from India, to work in the sugar-cane plantations in the KwaZulu-Natal Province. The local Indian community was further augmented by “passenger” immigrants who paid for passage to South Africa. Extensive HLA allelic variability exists in mainland Indian populations. We investigated HLA-A, -B and -C allele and haplotype diversity in 50 healthy, unrelated individuals recruited from the South African Indian population for comparison to data from mainland India.     

Flow cytometry analysis of OKT4 epitope deficiency in South African black children.

A case of OKT4 epitope deficiency referred for investigation with suspected immunodeficiency is described. Flow cytometry analysis of OKT4 epitope deficiency in a study group of healthy black children showed different manifestations of the lack of OKT4 epitope; a complete lack of OKT4+CD4+ peripheral blood lymphocytes (PBL) with normal numbers of OKT4A+ and Leu3a-CD4+ PBL, decreased percentage OKT4+CD4+ compared with OKT4A+ and Leu-3a+CD4+ PBL, decreased fluorescent staining intensity with OKT4 and a biphasic OKT4 staining pattern associated with a reduced OKT4/Leu-3a ratio. The percentage and fluorescent intensity of OKT4+CD4+ PBL in the study group were significantly lower (P < 0.0001) than Leu-3a+CD4+ and OKT4A+CD4+ PBL. There is thus considerable risk of under-estimating the number of CD4+ cells in black South Africans if the OKT4 MoAb is used.