South African Medical Journal - Volume 103, Issue 12, 2013
Volumes & issues
Volume 103, Issue 12, 2013
A comparison of the pharmacokinetics of Aspen Ceftriaxone and Rocephin in community-acquired meningitis : researchSource: South African Medical Journal 103, pp 906 –909 (2013)More Less
Background. Community-acquired bacterial meningitis (CABM) is a life-threatening condition that is common among immune-compromised individuals. Intravenous ceftriaxone, of which Rocephin (ROC) is the originator brand, is recommended as first-line therapy in South Africa. Despite concerns regarding therapeutic equivalence with generic agents, this is the first study that has been conducted comparing clinical pharmacokinetics (PK) of a generic ceftriaxone formulation with the originator.
Objective. To compare the PK and safety of Aspen Ceftriaxone (AC) and ROC in the treatment of adult CABM.
Methods. A total of 63 eligible patients were randomised 1:1 to receive 2 g of either medication twice daily for a duration based on the identity of the causative organism and their physician's clinical judgment. The primary endpoint of this study was the comparison of clinical PK, specifically the concentrations of each drug in the cerebrospinal fluid with corresponding paired plasma samples. While this study was underpowered to assess efficacy, safety could be evaluated on the basis of reported adverse events.
Results. The two patient groups were epidemiologically similar. There were no statistically significant differences in PK between either agent, nor any difference with regard to safety.
Conclusion. AC can be considered as equivalent to ROC with regard to PK and safety in patients with CABM.
Source: South African Medical Journal 103, pp 910 –915 (2013)More Less
Background. Identifying children at the highest risk of negative health effects is a prerequisite to effective public health policies in Southern Africa. A central ongoing debate is whether poverty, orphanhood or parental AIDS most reliably indicates child health risks. Attempts to address this key question have been constrained by a lack of data allowing distinction of AIDS-specific parental death or morbidity from other causes of orphanhood and chronic illness.
Objectives. To examine whether household poverty, orphanhood and parental illness (by AIDS or other causes) independently or interactively predict child health, developmental and HIV-infection risks.
Methods. We interviewed 6 002 children aged 10 - 17 years in 2009 - 2011, using stratified random sampling in six urban and rural sites across three South African provinces. Outcomes were child mental health risks, educational risks and HIV-infection risks. Regression models that controlled for socio-demographic co-factors tested potential impacts and interactions of poverty, AIDS-specific and other orphanhood and parental illness status.
Results. Household poverty independently predicted child mental health and educational risks, AIDS orphanhood independently predicted mental health risks and parental AIDS illness independently predicted mental health, educational and HIV-infection risks. Interaction effects of poverty with AIDS orphanhood and parental AIDS illness were found across all outcomes. No effects, or interactions with poverty, were shown by AIDS-unrelated orphanhood or parental illness.
Conclusions. The identification of children at highest risk requires recognition and measurement of both poverty and parental AIDS. This study shows negative impacts of poverty and AIDS-specific vulnerabilities distinct from orphanhood and adult illness more generally. Additionally, effects of interaction between family AIDS and poverty suggest that, where these co-exist, children are at highest risk of all.
Source: South African Medical Journal 103, pp 916 –917 (2013)More Less
Background. Blood transfusions (BTFs) are not without risk and pose a significant financial burden on resource-limited services. In line with current international evidence, the nursery at Groote Schuur Hospital (GSH), Cape Town, South Africa, introduced a restrictive BTF protocol to minimise transfusions and manage costs.
Objective. To determine whether adopting a restrictive BTF policy results in fewer transfusions.
Methods. Data were retrospectively collected on all infants who received BTFs in the GSH nursery over a 6-month period following adoption of a restrictive BTF policy in 2010. BTF figures for a similar time period before the restrictive policy, during 2008, were obtained for comparison.
Results. After introduction of the restrictive BTF policy, 42 of 1 097 infants admitted (3.8%) received a total of 64 BTFs. In comparison, 102 of a total of 940 infants (10.9%) admitted during a period of the same length before introduction of the restrictive BTF policy received a total of 121 transfusions. Comparison between the number of BTFs administered before and after the restrictive policy showed a highly statistically significant difference (p<0.001). The total cost of the blood products used in the two 6-month periods was R91 870 v. R48 640, based on current prices.
Conclusions. By adopting a restrictive policy, we were able to halve the number of BTFs, reduce risks associated with transfusions, and achieve significant cost benefits. Following evidence-based guidelines results in high standards of care, while also making the most effective use of resources.
Source: South African Medical Journal 103, pp 918 –920 (2013)More Less
Background. Blood cultures (BCs) are frequently performed in sick children. A recent audit of BCs among adult patients documented high rates of contamination by coagulase-negative staphylococci (CoNS).
Objectives. To describe BC contamination rates and common pathogenic organisms causing bloodstream infection in children at a tertiary-level children's hospital.
Methods BC results for children admitted to Red Cross War Memorial Children's Hospital from 2008 to 2012 were extracted from the National Health Laboratory Service database. Pathogenic and non-pathogenic (contaminated) growth on BCs in children <1 year of age and >1 year of age, were analysed. Data analysis was performed using Epi Info version 3.5.1.
Results A total of 47 677 BCs were performed in the 5-year period. The proportion of contaminated specimens ranged between 5.9% and 7.2% per year (p=0.4). CoNS was the predominant isolate in 53.8% of all contaminated BCs. Children <1 year of age experienced higher contamination rates than children >1 year of age (8.7% v. 4.7%; relative risk 1.84; 95% confidence interval (CI) 1.71 - 1.97). Pathogenic organisms were isolated in 6.2% (95% CI 6.0 - 6.4) of all BC specimens. Among Gram-positive organisms, the proportion of Streptococcus pneumonia isolates declined from 14.3% to 4.7% (p< 0.00001), while there was a significant increase in Gram-negative organisms (51.8% - 57.9%; p=0.04) over the 5-year period. Klebsiella pneumonia, the predominant Enterobacteriaceae isolated, decreased from 45.8% to 31.7% (p=0.004).
Conclusion This study identified unacceptably high BC contamination rates, emphasising the importance of collecting BC specimens under sterile conditions.
Effectiveness of sequential v. standard triple therapy for treatment of Helicobacter pylori infection in children in Nairobi, Kenya : researchSource: South African Medical Journal 103, pp 921 –924 (2013)More Less
Background. Once the diagnosis of Helicobacter pylori is confirmed, treatment requires at least two antibiotics and an acid inhibitor for a minimum of seven days. Unfortunately, treatment failures are being frequently reported. Treatment regimens that include sequential administration of antibiotics with acid inhibitors have been developed to try and increase the rate of eradication.
Objective. To determine the effectiveness of a novel 10-day sequential therapy compared with the standard 10-day triple therapy for treatment of H. pylori infection in children.
Methods. A double-blinded, randomised, controlled trial was conducted. Children under the age of 16 years with recurrent abdominal pain associated with dyspepsia and diagnosed with H. pylori by histology were randomly allocated either to a 10-day sequential treatment regimen or to a 10-day conventional triple therapy. Analysis of the outcome of this study was based on clinical improvement and confirmed H. pylori eradication based on stool H. pylori antigen detection and/or repeat endoscopy.
Results. Of the 71 patients included in the analysis, 45 (63.4%) were given the 10-day conventional treatment while 26 (36.6%) received the 10-day sequential treatment. There was no difference in clinical improvement after treatment in the two therapies. However, there was a significant difference in the eradication of H. pylori between the conventional v. sequential regimens (48.8% v. 84.6%, respectively; p=0.02, odds ratio 0.19).
Conclusion. The sequential treatment had a significantly higher H. pylori eradication rate than the conventional treatment.
Combined paediatric liver-kidney transplantation : analysis of our experience and literature review : researchSource: South African Medical Journal 103, pp 925 –929 (2013)More Less
Background. Renal insufficiency is increasingly common in end-stage liver disease and allocation of livers to this category of patient has escalated. The frequency of combined liver-kidney transplantation (CLKT) has consequently increased. Indications for CLKT in children differ from those for adults and typically include rare congenital conditions; subsequently limited numbers of this procedure have been performed in paediatric patients worldwide. Scant literature exists on the subject.
Methods. Subsequent to institutional approval, a retrospective chart analysis of all paediatric CLKTs performed at the Transplant Unit, Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa between January 2005 and July 2013 was conducted.
Results. Defining children as younger than 18 years of age, 43 patients had received a liver transplant since 2005, of whom 8 received a CLKT. Indications included autosomal recessive polycystic kidney disease (n=3), primary hyperoxaluria type 1 (n=4) and heterozygous factor H deficiency with atypical haemolytic uraemic syndrome (n=1). Graft combinations included whole liver and one kidney (n=5), whole liver and two kidneys (n=1) and left lateral liver segment and one kidney (n=2), all from deceased donors. Patient age ranged from 4 to 17 years (median 9) and included 4 females and 4 males. Weight ranged from 13 to 42 kg (median 22.5). We describe one in-hospital mortality. The remaining 7 patients were long-term survivors with a survival range from 6 to 65 months.
Conclusions. Although rarely indicated in children, CLKT is an effective treatment option, appropriately utilising a scarce resource and significantly improving quality of life in the recipient.
Internship training adequately prepares South African medical graduates for community service - with exceptions : researchSource: South African Medical Journal 103, pp 930 –934 (2013)More Less
Background. The 2-year internship period for medical graduates began in South Africa in 2005 and has never been formally evaluated.
Objective. This study assessed the perceptions of community service medical officers (COSMOs) working at district hospitals (DHs) in KwaZulu-Natal (KZN) to determine whether the 2-year internship programme had adequately prepared them for community service (CS).
Method. A cross-sectional descriptive study was conducted regarding the perceptions of COSMOs working at 22 district hospitals in KZN. Data were collected in July 2012, using a questionnaire based on the core skills and knowledge detailed in the Health Professions Council of South Africa intern log book. All eight domains were self-assessed and a score of 4 out of 5 indicated an ability to work independently.
Results. Of the COSMOs, 78% (60 out of 89) completed the questionnaire. Most felt well-prepared for CS in all disciplines, but critical gaps in knowledge and skills were identified in paediatrics, orthopaedics, anaesthetics and obstetrics. In addition, 75% of respondents (45 out of 60) expressed a need for additional training in the disciplines of ear, nose and throat (ENT), urology, ophthalmology and dermatology.
Conclusion. The 2-year internship has provided the basis for independent medical practice in DHs. However, certain critical skill gaps need urgent attention, particularly in obstetrics and anaesthesia. Areas of weakness in ENT, urology, ophthalmology and dermatology could be addressed by including these specialities as a compulsory rotation in surgery, medicine or family medicine during internship training.
A follow-up cross-sectional study of environmental lead exposure in early childhood in urban South Africa : researchSource: South African Medical Journal 103, pp 935 –938 (2013)More Less
Background. Lead exposure has significant detrimental effects on the health and wellbeing of children. In resource-poor countries, information on the extent of lead exposure is often inadequate owing to the lack of surveillance and screening programmes.
Objective. To determine the degree of lead exposure in children residing in South African urban areas.
Methods. A cross-sectional survey was conducted in schools in Johannesburg, Cape Town and Kimberley in 2007 - 2008. Blood lead levels were assessed in a total of 1 349 grade 1 children using the LeadCare Analyser system. Parents completed a structured questionnaire on socio-demographic profiles and risk factors to provide information about socioeconomic status and other risk factors for lead exposure.
Results. Blood lead levels ranged from 0.8 - 32.3 µg/dl. The mean blood lead level in the total sample was 7.97 µg/dl; 74% had blood lead levels ≥5 µg/dl. The highest proportion (84%) of children with blood lead levels ≥5 µg/dl was in Johannesburg. In the multivariate analysis, socioeconomic status was significantly associated with blood lead levels ≥5 µg/dl.
Conclusion. Lead exposure in South African urban areas remains widespread. The risk of lead poisoning in some areas and certain groups of children may be increasing despite the phasing out of lead-containing petrol. Children living in poverty continue to be the most vulnerable.
Chronic diseases are not being managed effectively in either high-risk or low-risk populations in South Africa : researchSource: South African Medical Journal 103, pp 938 –941 (2013)More Less
Background. Primary healthcare is the foundation of a country's healthcare system. Without an efficient and cost-effective programme, the level of healthcare offered across all levels of health management is adversely affected.
Objective. To analyse the effectiveness of the management of hypertension and diabetes mellitus (DM) among two distinct patient populations, one with significant cardiovascular risk factors and the other without.
Method. We performed a case control study of a high-risk group of patients presenting with chronic critical limb ischaemia (CLI) to the Divisions of Vascular Surgery at Charlotte Maxeke Johannesburg Academic Hospital and Chris Hani Baragwanath Academic Hospital, and a randomly selected group of 'healthy' community participants from Johannesburg's South Western Townships (Soweto).
Results. We assessed 217 patients with CLI and 1 030 participants from the community. We assessed the number of patients who were not achieving their therapeutic targets, among those known to be hypertensive (CLI: 44.7%; community: 59.9%) and diabetic (CLI: 83.5%; community: 66%). Undiagnosed diabetes affected 10.8% of patients with CLI and 11% of the community sample.
Conclusion. Traditional vascular risk factors are managed poorly at both primary healthcare and at tertiary care levels. There is a need to identify factors that will address this issue.
Relationship between environmental exposure to pesticides and anthropometric outcomes of boys in the rural Western Cape, South Africa : researchSource: South African Medical Journal 103, pp 942 –947 (2013)More Less
Background. Rural residents in the Western Cape (WC), South Africa (SA) are highly exposed to agricultural pesticides that could impact their reproductive development. However, epidemiological evidence of the effect of pesticides on pubertal growth is contradictory.
Objective. To investigate the effect of pesticide exposure measured using indices of environmental exposure to pesticides on the pubertal growth of boys in rural WC, SA.
Methods. A cross-sectional study of 269 boys (177 of whom gave a history of residing on farms) was conducted. A questionnaire was administered, height and weight were measured and body mass index was calculated. A proximity index (PI) and spraying index (SI) was developed, measuring the lifetime average home distance from pesticide spraying and average frequency of spraying pesticides on a farm, respectively.
Results. Median age of boys was 12.4 years (interquartile range 9.5 - 13.3). More than 60% boys had height and weight <50th percentile for age. After adjusting for confounders, PI was significantly associated with shorter stature and lower weight (-1.7 cm/10-fold decrease, p=0.02 and -1.24 kg/10-fold decrease, p=0.04; respectively) and SI was non-significantly associated (-1.4 cm/10-fold increase, p=0.05 and -1.1 cm/10-fold increase, p=0.06; respectively). Associations were stronger for boys aged <11 years and were weaker when excluding non-farm boys. There were no other associations between outcome and exposure.
Conclusions. The use of quantitative exposure indices showed that lower heights and weights might be associated with pesticide exposure in farm boys v. non-farm boys, but not among farm boys. Lower anthropometric measurements among farm boys v. non-farm boys appear stronger at a younger age. The indices of environmental exposure to pesticides require further development.
Management of acute fever in children : guideline for community healthcare providers and pharmacists : guidelineSource: South African Medical Journal 103, pp 948 –954 (2013)More Less
Fever is a normal physiological response to illness that facilitates and accelerates recovery. Although it is often associated with a self-limiting viral infection in children, it may also be a presenting symptom of more serious conditions requiring urgent medical care. Therefore, it is essential to distinguish between a child with fever who is at high risk of serious illness and who requires specific treatment, hospitalisation or specialist care, and those at low risk who can be managed conservatively at home. This guideline aims to assist pharmacists, primary healthcare workers and general practitioners in risk-stratifying children who present with fever, deciding on when to refer, the appropriate use of antipyretic medication and how to advise parents and caregivers.
Source: South African Medical Journal 103 (2013)More Less
Trefor Jenkins is a true Welshman, born in Wales at Merthyr Tydfil on 24 July, 1932, in a Glamorgan coal mining valley and within a coal mining family. He lived with his extended family and went to school at the local junior school and on to the grammar school. He then moved to London to study medicine at King's College, University of London, and Westminster Hospital. After graduating in 1956, he took a position in the Royal Army Medical Corps, then one with the South Wales Regional Hospital Board. He emigrated to Zimbabwe (then Southern Rhodesia) in 1960 to take up a post as medical officer at the Wankie Colliery Hospital. There he first came across sickle cell anaemia, which stimulated his life-long interest in both haematology and genetics. With a young family, he moved to South Africa to work firstly in a Durban hospital and then in Johannesburg at the University of the Witwatersrand Medical School (where he says he found his academic home), with Professor Philip Tobias, in Anatomy.
Human genetics in Johannesburg, South Africa : past, present and future : Festschrift : Professor Trefor Jenkins - medical geneticsSource: South African Medical Journal 103, pp 957 –961 (2013)More Less
Genetic services were set up in Johannesburg, South Africa, in the late 1960s, but only became widespread and formalised after the first Professor of Human Genetics, Trefor Jenkins, was installed at the University of the Witwatersrand in 1974. The first services involved chromosome studies, and these developed into genetic counselling services. Prenatal diagnosis began to be offered, particularly for older women at risk for chromosome abnormalities in the fetus, and those at risk for neural tube defects. Genetic screening was then initiated for the Jewish community because of their high carrier rate for Tay-Sachs disease. Educational courses in human genetics were offered at Wits Medical School, and medical as well as other health professionals began to be trained. Research, supported by national and international bodies, was integral in the activities of the Department (now Division) of Human Genetics and focused on genetic conditions affecting the generally understudied black community. In the late 1980s the first training programme for genetic counsellors was started at MSc level, and postgraduate scientists at MSc and PhD levels studied in and qualified through the Department. At the same time molecular genetic laboratories were set up. In the late 1990s training for medical geneticists was initiated. Extensive high-quality genetic services developed over the four decades were comparable to those of most other departments in developed countries.
The elusive gene for keratolytic winter erythema : Festschrift : Professor Trefor Jenkins - medical geneticsSource: South African Medical Journal 103, pp 961 –965 (2013)More Less
Keratolytic winter erythema (KWE), also known as Oudtshoorn skin disease, is characterised by a cyclical disruption of normal epidermal keratinisation affecting primarily the palmoplantar skin with peeling of the palms and soles, which is worse in the winter. It is a rare monogenic, autosomal dominant condition of unknown cause. However, due to a founder effect, it occurs at a prevalence of 1/7 200 among South African Afrikaans-speakers. In the mid-1980s, samples were collected from affected families for a linkage study to pinpoint the location of the KWE gene. A genome-wide linkage analysis, using microsatellite markers, identified the KWE critical region on chromosome 8p23.1-p22. Subsequent genetic studies focused on screening candidate genes in this critical region; however, no pathogenic mutations that segregated exclusively with KWE were identified. The cathepsin B (CTSB) and farnesyl-diphosphate farnesyltransferase 1 (FDFT1) genes revealed no potentially pathogenic variants, nor did they show differential gene expression in affected skin. Mutation detection in additional candidate genes also failed to identify the KWE-associated variant, suggesting that the causal variant may be in an uncharacterised functional region. Bioinformatic analysis revealed highly conserved regions within the KWE critical region and a custom tiling array was designed to cover this region and to search for copy number variation. Although the study did not identify a variant that segregates exclusively with KWE, it provided valuable insight into the complex KWE-linked region. Next-generation sequencing approaches are being used to comb the region, but the causal variant for this interesting hyperkeratotic palmoplantar phenotype still remains elusive.
Thyroid dysfunction in a cohort of South African children with Down syndrome : Festschrift : Professor Trefor Jenkins - medical geneticsSource: South African Medical Journal 103, pp 966 –970 (2013)More Less
Background. While international studies show thyroid dysfunction occurs more commonly in individuals with Down syndrome (DS) than in the general population, there is a paucity of available data from sub-Saharan Africa.
Objectives. To document the range of thyroid function in a cohort of South African children with DS, and to assess referral and treatment practices when thyroid dysfunction was present.
Methods. A retrospective file-based study of 391 children with DS seen at the genetic clinics at three Johannesburg hospitals from 2003 to 2008. Thyroid function test (TFT) results (thyroid-stimulating hormone and free thyroxine) and demographic details were collected for each child. Endocrine clinic files from two of the hospitals were reviewed for additional referral and treatment information.
Results. The majority (83.6%) of children had at least one TFT, in most cases performed between the ages of 2 and 12 months. The most common form of thyroid dysfunction was subclinical hypothyroidism (SCH) (28.7%). Up to one-third of the patients, including several neonates with abnormal results, were not referred for further evaluation and were therefore not receiving the necessary treatment. Inter-laboratory biochemical discrepancies and lack of population-specific reference ranges complicated the interpretation of results. The controversy surrounding whether, and how, to treat SCH influenced treatment practices.
Conclusions. Thyroid dysfunction is prevalent in South African children with DS. There is an urgent need to address the laboratory biochemical discrepancies, and to establish guidelines for surveillance and treatment to prevent further irreversible neurological and physical impairment.
Fanconi anaemia in black South African patients heterozygous for the FANCG c.637-643delTACCGCC founder mutation : Festschrift : Professor Trefor Jenkins - medical geneticsSource: South African Medical Journal 103, pp 970 –973 (2013)More Less
Background. Fanconi anaemia (FA) is an autosomal recessive, genetically heterogeneous disorder, characterised by interstrand crosslink-induced chromosome breaks, congenital abnormalities and predisposition to malignancies. It has a prevalence of about 1/40 000 in black South Africans (SAs). A founder mutation in the FANCG gene occurs in the homozygous state in 77.5% of southern African blacks.
Objective. To locate additional pathogenic mutations in the FANCG gene of black FA patients who were heterozygous for the founder mutation.
Methods. Further mutation analysis of the FANCG gene was undertaken in 7 patients clinically suspected of having FA. The parents of two of the patients were tested for the presence of the founder mutation to determine true heterozygosity in the patients. To clarify whether or not previously unreported variants were pathogenic, 58 random black SA individuals were screened.
Results. Three novel single base pair deletions, resulting in frameshift mutations (c.247delA, c.179delT and c.899delT) were identified in 3/7 patients. A fourth patient was found to have a single base substitution resulting in a splice site mutation (c.1636+1G>A). The remaining three patients were not found to harbour any pathogenic mutations. Two non-pathogenic variants were also identified among the seven patients.
Conclusion. The results of this small sample suggest that a second common mutation in the FANCG gene is unlikely in this population. However, FANCG sequencing should be performed on patients heterozygous for the common founder mutation to attempt to confirm their diagnosis.
Neural tube defects in Gauteng, South Africa : recurrence risks and associated factors : Festschrift : Professor Trefor Jenkins - medical geneticsSource: South African Medical Journal 103, pp 973 –977 (2013)More Less
Objectives. To (i) determine the recurrence risks of NTDs in the population of Gauteng; (ii) investigate some of the risk factors shown to be important in the occurrence of NTDs in other populations; and (iii) determine their relative importance in the aetiology of NTDs in the Gauteng population.
Methods. A retrospective study was undertaken of 640 families with a member with an NTD. Data were collected from the genetic counselling files held in the Department of Human Genetics for a 28-year period.
Results. A recurrence risk ± standard deviation (SD) for NTDs of 2.28±0.9% (1/45) was calculated for the population. There was no significant difference between the risk of recurrence 0.73±1.0% for the black families (n=98) compared with those for the total sample (N=621). The risk rose to 4.16% after giving birth to two affected children. Analysis of the gender of those with NTDs showed that significantly more female infants (male:female ratio 0.82) were affected. The study also showed that while maternal age was not a significant risk factor for the occurrence of NTDs, maternal parity did play a role, and first and last children were at increased risk. In addition, a higher occurrence of spontaneous abortions and of apparently unrelated congenital malformations in other offspring was found in families with a child with an NTD.
Conclusions. This study provides unique information relevant to the genetic counselling of families with a member with an NTD in our population. All affected families should be referred to a genetics service for appropriate counselling.
Haematological implications of folate food fortification : Festschrift : Professor Trefor Jenkins - medical geneticsAuthor J. MetzSource: South African Medical Journal 103, pp 978 –981 (2013)More Less
Reports from some Western countries indicate that mandatory folate food fortification (FFF) has substantially reduced the prevalence of folate deficiency, leading to calls for folate testing following FFF to be limited to specific indications such as macrocytic anaemia. This is premature for low-income countries, where folate deficiency is predominantly the result of poor intake coupled with the increasing demand in pregnancy. There is also evidence that HIV infection is prejudicial to folate nutrition, and low-income HIV-infected women and their offspring could be among the most susceptible to folate deficiency. In assessing folate nutrition, the value of serum folate has been compromised by FFF, and both serum and red cell folate are necessary for optimal assessment of folate status. Although the limited data available suggest that large-scale masking of vitamin B12 deficiency by FFF has not occurred, it has been suggested that B12 be incorporated into folate-fortified foods. However, significant B12 deficiency is usually due to malabsorption, and physiological doses added to food would be of questionable value because they would not be absorbed. Extensive work, especially randomised clinical trials, must be done before dietary intervention with B12 on a national scale can be justified.
The molecular basis of mutagenesis - 40 years of research on genomic integrity : Festschrift : Professor Trefor Jenkins - molecular geneticsAuthor E.C. FriedbergSource: South African Medical Journal 103, pp 982 –983 (2013)More Less
Biology and genetics of oculocutaneous albinism and vitiligo - common pigmentation disorders in southern Africa : Festschrift : Professor Trefor Jenkins - molecular geneticsSource: South African Medical Journal 103, pp 984 –988 (2013)More Less
Pigmentation disorders span the genetic spectrum from single-gene autosomal recessive disorders such as oculocutaneous albinism (OCA), the autosomal dominant disorder piebaldism to X-linked ocular albinism and multifactorial vitiligo. OCA connotes a group of disorders that result in hypopigmented skin due to decreased melanin production in melanocytes and loss of visual acuity. There are four non-syndromic forms, OCA1-4, which are classified based on the gene that is mutated (tyrosinase, OCA2, tyrosinase-related protein 1 and SLC45A2, respectively). Despite the fact that multiple genes account for the various forms of OCA, the phenotypes of all four forms result from disruption in the maturation and trafficking of the enzyme tyrosinase. OCA2 is the most prevalent autosomal recessive disorder among southern African blacks, affecting 1/3 900 individuals; while OCA3, although rare, is most prevalent in southern Africa. Another common pigmentation disorder in southern Africa is vitiligo, which affects 1 - 2% of people worldwide. Vitiligo is a complex, acquired disorder in which melanocytes are destroyed due to an autoimmune response. The aetiology underlying this disorder is poorly understood, although recent genetic association studies have begun to shed light on the contributing factors. Pigmentation disorders have significant psychosocial implications and co-morbidities, yet therapies are still lacking. Recent progress in our understanding of the pathobiology of both albinism and vitiligo may herald novel treatment strategies for these disorders.