Clinical, biochemical, and genetic spectrum of MADD in a South African cohort: an ICGNMD study.

BACKGROUND: Multiple acyl-CoA dehydrogenase deficiency (MADD) is an autosomal recessive disorder resulting from pathogenic variants in three distinct genes, with most of the variants occurring in the electron transfer flavoprotein-ubiquinone oxidoreductase gene (ETFDH). Recent evidence of potential founder variants for MADD in the South African (SA) population, initiated this extensive investigation. As part of the International Centre for Genomic Medicine in Neuromuscular Diseases study, we recruited a cohort of patients diagnosed with MADD from academic medical centres across SA over a three-year period. The aim was to extensively profile the clinical, biochemical, and genomic characteristics of MADD in this understudied population. METHODS: Clinical evaluations and whole exome sequencing were conducted on each patient. Metabolic profiling was performed before and after treatment, where possible. The recessive inheritance and phase of the variants were established via segregation analyses using Sanger sequencing. Lastly, the haplotype and allele frequencies were determined for the two main variants in the four largest SA populations. RESULTS: Twelve unrelated families (ten of White SA and two of mixed ethnicity) with clinically heterogeneous presentations in 14 affected individuals were observed, and five pathogenic ETFDH variants were identified. Based on disease severity and treatment response, three distinct groups emerged. The most severe and fatal presentations were associated with the homozygous c.[1067G > A];c.[1067G > A] and compound heterozygous c.[976G > C];c.[1067G > A] genotypes, causing MADD types I and I/II, respectively. These, along with three less severe compound heterozygous genotypes (c.[1067G > A];c.[1448C > T], c.[740G > T];c.[1448C > T], and c.[287dupA*];c.[1448C > T]), resulting in MADD types II/III, presented before the age of five years, depending on the time and maintenance of intervention. By contrast, the homozygous c.[1448C > T];c.[1448C > T] genotype, which causes MADD type III, presented later in life. Except for the type I, I/II and II cases, urinary metabolic markers for MADD improved/normalised following treatment with riboflavin and L-carnitine. Furthermore, genetic analyses of the most frequent variants (c.[1067G > A] and c.[1448C > T]) revealed a shared haplotype in the region of ETFDH, with SA population-specific allele frequencies of < 0.00067-0.00084%. CONCLUSIONS: This study reveals the first extensive genotype-phenotype profile of a MADD patient cohort from the diverse and understudied SA population. The pathogenic variants and associated variable phenotypes were characterised, which will enable early screening, genetic counselling, and patient-specific treatment of MADD in this population.

An Overview of Benefits and Challenges of Rare Disease Biobanking in Africa, Focusing on South Africa.

The North-West University's Centre for Human Metabolomics (CHM) is in the process of establishing the first rare disease (RD) biobank in South Africa and Africa. The CHM Biobank's main focus is on the collection of samples and information for rare congenital disorders. Approximately 72% of all RDs have a genetic origin, of which 70% have an exclusive pediatric onset. The need for such a biobank was identified by the CHM diagnostic laboratory. Feedback toward this initiative was overwhelmingly positive at the first stakeholder meeting in August 2019. However, gaining support from the public sector and recruiting of participants have proven to be challenging. Problems experienced to date include lack of support from government and clinicians; lack of knowledge on RDs (patients and clinicians); public health care focus not directed toward RDs; patients not returning for follow-up visits; and unwillingness to participate due to fear of exploitation. The CHM Biobank's vision and goals are aligned to address a national and international research need: it will provide a valuable resource for scientists to improve what is known about these diseases; to better understand the natural history and pathophysiology; to optimize diagnostic methods; and to potentially develop treatments. The genetic variability of the South African population provides added value to the RD biobank. This review provides a brief overview of the literature on the challenges and benefits of an RD biobank and how this relates to low- and middle-income countries (LMIC) like South Africa. The aim of the review is to draw attention to the potential benefits of such an undertaking and to create awareness, at both local and global level, toward some of the unique collective considerations that an RD biobank in LMIC (also unique South African challenges) faces on an operational, collaborate, and sustainability level.

Randomized control trial of oral arginine therapy for children with sickle cell anemia hospitalized for pain in Nigeria.

Low arginine bioavailability is associated with vaso-occlusive painful crisis (VOC) severity in sickle cell anemia (SCA) and predicts need for pediatric hospitalization. Intravenous arginine therapy has opioid-sparing effects and was found to significantly decrease pain scores in children hospitalized with SCA-VOC in a phase-two randomized placebo-controlled trial (RCT). Efficacy of oral arginine is unknown. Our objective was to determine the safety and efficacy of oral arginine therapy in Nigerian children with SCA. A double-blind RCT of oral L-arginine-hydrochloride (100 mg/kg TID) was conducted in children with SCA-VOC, aged 5-17 years, hospitalized at two Nigerian sites. The primary outcome measure was analgesic usage, quantified by difference in the mean Analgesic Medication Quantification Scale (MQS). Secondary outcomes included daily pain scores, time-to-crisis-resolution and length-of-hospital-stay. An intention-to-treat analysis was performed. Sixty-eight children (age 5-17 years, mean 10.6 ± 0.4 years; 56% male), were randomized to receive L-arginine (35 patients) or placebo (33 patients). The mean total MQS for the arginine group was 73.4 (95% CI, 62.4-84.3) vs 120.0 (96.7-143.3) for placebo (P < .001). The mean rate of decline in worst pain scores was faster in the arginine arm vs placebo (1.50 [1.23-1.77] vs 1.09 [0.94-1.24] point/d, P = .009). Children receiving arginine had a shorter time-to-crisis-resolution (P = .02), shorter hospital-stay (P = .002) and experienced no serious adverse event. Pain control was more rapid, total analgesic requirement was significantly reduced, and most notably, time-to-crisis-resolution and length-of-hospital-stay were shorter in children with SCA-VOC receiving arginine vs placebo. Given the established safety and low cost, oral arginine is a promising adjuvant therapy for SCA-VOC management.

Challenges and Opportunities for Biological Mass Spectrometry Core Facilities in the Developing World.

The developing world is seeing rapid growth in the availability of biological mass spectrometry (MS), particularly through core facilities. As proteomics and metabolomics becomes locally feasible for investigators in these nations, application areas associated with high burden in these nations, such as infectious disease, will see greatly increased research output. This article evaluates the rapid growth of MS in South Africa (currently approaching 20 laboratories) as a model for establishing MS core facilities in other nations of the developing world. Facilities should emphasize new services rather than new instruments. The reduction of the delays associated with reagent and other supply acquisition would benefit both facilities and the users who make use of their services. Instrument maintenance and repair, often mediated by an in-country business for an international vendor, is also likely to operate on a slower schedule than in the wealthiest nations. A key challenge to facilities in the developing world is educating potential facility users in how best to design experiments for proteomics and metabolomics, what reagents are most likely to introduce problematic artifacts, and how to interpret results from the facility. Here, we summarize the experience of 6 different institutions to raise the level of biological MS available to researchers in South Africa.

The analysis of illicit methaqualone containing preparations by gas chromatography-mass spectrometry for forensic purposes.

A validated gas chromatographic-mass spectrometric method for quantitative analysis of methaqualone (MTQ) in illicit preparations is reported. The method proved to have a coefficient of variation of below 5%. Four batches of seized tablets, two pairs with similar imprints, were analyzed. It was found that the average MTQ concentration in all four batches of tablets differed significantly (p = 0.01) rendering it impossible to conclude that, on the basis of MTQ concentration alone, the batches with a similar logo originated from the same manufacturer or manufacturing batch. Conversely, it can be said that in this case, the four batches originated from either different clandestine laboratories or manufacturing batches.