A novel mitochondrial DNA variant in MT-ND6: m.14430A>C p.(Trp82Gly) identified in a patient with Leigh syndrome and complex I deficiency.

Leigh syndrome is a severe progressive mitochondrial disorder mainly affecting children under the age of 5 years. It is caused by pathogenic variants in any one of more than 75 known genes in the nuclear or mitochondrial genomes. A 19-week-old male infant presented with lactic acidosis and encephalopathy following a 2-week history of irritability, neuroregression and poor weight gain. He was hypotonic with pathological reflexes, impaired vision, and nystagmus. Brain MRI showed extensive bilateral symmetrical T2 hyperintense lesions in basal ganglia, thalami, and brainstem. Metabolic workup showed elevated serum alanine, and heavy lactic aciduria with increased ketones, fumarate, malate, and alpha-ketoglutarate as well as reduced succinate on urine organic acid analysis. Lactic acidemia persisted, with only a marginally elevated lactate:pyruvate ratio (16.46, ref. 0-10). He demised at age 7 months due to respiratory failure. Exome sequencing followed by virtual gene panel analysis for pyruvate metabolism and mitochondrial defects could not identify any nuclear cause for Leigh syndrome. Mitochondrial DNA (mtDNA) genome sequencing revealed 88% heteroplasmy for a novel variant, NC_012920.1(MT-ND6):m.14430A>C p.(Trp82Gly), in blood DNA. This variant was absent from the unaffected mother's blood, fibroblast, and urine DNA, and detected at a level of 5% in her muscle DNA. Mitochondrial respiratory chain analysis revealed markedly reduced mitochondrial complex I activity in patient fibroblasts (34% of parent and control cells), and reduced NADH-linked respirometry (less than half of parental and control cells), while complex II driven respirometry remained intact. The combined clinical, genetic, and biochemical findings suggest that the novel MT-ND6 variant is the likely cause of Leigh syndrome in this patient. The mitochondrial ND6 protein is a subunit of complex I. An interesting finding was the absence of a significantly elevated lactate:pyruvate ratio in the presence of severe lactatemia, which directed initial diagnostic efforts towards excluding a pyruvate metabolism defect. This case highlights the value of a multidisciplinary approach and complete genetic workup to diagnosing mitochondrial disorders in South African patients.

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.

Vitamin D abnormalities and bone turn over analysis in children with epilepsy in the Western Cape of South Africa.

PURPOSE: The effects of antiseizure medications (ASMs) on bone metabolism is inconsistent. Most studies are in high income settings and none from sub-Saharan Africa. METHODS: A hospital based cross-sectional study in a paediatric epilepsy service with a comparison group assessed vitamin D metabolism. RESULTS: Seventy-five children with epilepsy and 75 comparison group were recruited. Median age for children with epilepsy was 9 years (range 1-17 years) and controls 3 years (range 1-12 years). Vitamin D deficiency occurred in 11(16.2%) children with epilepsy versus 6 (8.8%) control group (p = 0.29). Vitamin D insufficiency occurred in 30 (44.1%) children with epilepsy compared to 27(39.7%) control group. Children on ASMs had lower mean vitamin D levels than the control group (p = 0.02). Children on enzyme-inducing ASMs had lower mean vitamin D levels (p = 0.08), vitaminD2 (p = 0.0018), vitaminD3 (p = 0.004), serum phosphate levels (p = 0.000), and higher mean parathyroid hormone levels (p = 0.03) compared to controls. There was no difference in dietary intake and ancestry, although the dietary content of both groups was low in vitamin D products. CONCLUSIONS: Low vitamin D levels were common in children from both groups, but statistically lower for the children on ASMs. Children on enzyme-inducing ASMs need screening for vitamin D deficiency. The literature supports extending this for all children on ASMs. This is the first study to report that children on enzyme-inducing ASMs have lower levels of Vitamin D2 and D3 levels, probably as result of increased destruction of vitamin D. Improved vitamin D intake for children in vulnerable settings is important.

Corynebacterium diphtheriae Native Aortic Valve Endocarditis in a Patient With Prosthetic Mitral Valve: A Rare Presentation.

Infective endocarditis due to non-toxigenic Corynebacterium diphtheriae is uncommon. We describe the case of a 42-year-old male with a history of mitral valve replacement with prosthetic valve for 4 years. He presented with fever, weight loss, dyspnea on exertion and orthopnea. The echocardiography demonstrated large vegetation attached on the left coronary cusp of the aortic valve with moderately severe aortic regurgitation but sparing of the prosthetic mitral valve. Three separate blood cultures grew Corynebacterium species. The patient underwent aortic valve replacement due to valvular dysfunction and congestive heart failure. C. diphtheriae DNA was detected by 16 S rDNA polymerase chain reaction (PCR) from the heart valve tissue. The patient recovered completely with combine antibiotics and surgical intervention. He was discharged from the hospital with good clinical outcome.

The First Case of Riboflavin Transporter Deficiency in sub-Saharan Africa.

This report describes the first case of a child with genetically confirmed Brown-Vialetto-van Laere syndrome in sub-Saharan Africa. This is an extremely rare clinical condition that presents with an auditory neuropathy, bulbar palsy, stridor, muscle weakness, and respiratory compromise that manifests with diaphragmatic and vocal cord paralysis. It is an autosomal recessive condition for which the genetic mutation has only recently been linked to a riboflavin transporter deficiency. We describe an 11-month-old affected male infant. He has required long-term respiratory support and a gastrostomy tube to support feeding. With high-dose riboflavin supplementation, he had limited recovery of motor function. His respiratory chain enzyme studies were abnormal suggestive of mitochondrial (mt) dysfunction. In the setting of limited resources, recognition of this striking clinical phenotype is important to highlight, specifically regarding the genetic implications of the condition and the potentially remedial response to vitamin supplementation.

Echocardiographic Features in Bartonella Endocarditis: A Case Series.

Bartonella spp. are emerging pathogens that are reported as the cause of blood culture-negative endocarditis ( BCNE). However, echocardiographic features and assessment of this endocarditis remains unclear. Four patients with B. henselae endocarditis were identified. All patients had underlying cardiac conditions: rheumatic heart disease in three, congenital heart disease in one. Evidence of vegetations was found on the aortic valve in all patients with large, highly mobile vegetations and severely destroyed valves demonstrated by the transthoracic echocardiogram leading to severe aortic regurgitation and heart failure. The vegetations were found on both the aortic and the mitral valve in two patients. All patients had negative blood cultures and underwent urgent valves replacement due to heart failure with good clinical outcome. The diagnosis of B. henselae endocarditis is based mainly on clinical suspicion in BCNE, specific serologic testing and polymerase chain reaction (PCR) detection on excised valve tissue.

First Case of Tricuspid Valve Endocarditis Caused by Gemella bergeri.

Gemella bergeri is a Gram-positive cocci species arranged in pairs and composes the normal flora of oral cavity, digestive and urinary tract. Several species of Gemella are known to cause endocarditis. Here, we report the first case in Thailand of G. bergeri endocarditis whose blood culture was negative using routine methods but was positive by PCR identification of bacteria in the affected valve. A 37-year-old male presented with prolonged fever, weight loss, and dyspnea on exertion. By transthoracic echocardiography, he was suspected of having infective endocarditis of the tricuspid valve. The patient underwent tricuspid valve repair and vegetectomy. Routine hospital blood cultures were negative but G. bergeri was identified by PCR/sequencing of the heart valve tissue.

Prospective comparison of infective endocarditis in Khon Kaen, Thailand and Rennes, France.

Prospectively collected, contemporary data are lacking on how the features of infective endocarditis (IE) vary according to region. We, therefore, compared IE in Rennes, France and Khon Kaen, Thailand. Fifty-eight patients with confirmed IE were enrolled at each site during 2011 and 2012 using a common protocol. Compared with French patients, Thais had a lower median age (47 versus 70 years old; P < 0.001) and reported more animal contact (86% versus 21%; P < 0.001). There were more zoonotic infections among Thai than France patients (6 and 1 cases; P = 0.017) and fewer staphylococcal infections (4 versus 15 cases; P = 0.011). Underlying rheumatic heart disease was more prevalent in Thai than in French patients (31% and 4%; P = 0.001), whereas prosthetic heart valves were less prevalent (9% and 35%; P = 0.001). Our data strengthen previous observations that IE in the tropics has distinctive demographic characteristics, risk factors, and etiologies and underscore the need for improved prevention and control strategies.

Common mutation causes cystinosis in the majority of black South African patients.

BACKGROUND: The mutations responsible for cystinosis in South African patients are currently unknown. A pertinent question is whether they are similar to those described elsewhere in the world. METHODS: Children who were being managed for cystinosis in the Western Cape Province of South Africa between 2002 and 2013 were studied. All underwent molecular analysis to detect sequence variations in the cystinosis gene. RESULTS: This cohort study included 20 patients, 13 of whom were Xhosa-speaking black South Africans and seven were Cape Coloureds (mixed race); none were Caucasian. All had nephropathic infantile-type cystinosis with evidence of proximal tubulopathy, with glycosuria and renal phosphate wasting. Diagnosis was confirmed in 19 cases by demonstrating an elevated cystine concentration in leukocytes. Molecular analysis of the cystinosin gene revealed that 19 patients had a G > A mutation in intron 11 (CTNS-c.971-12G > A p.D324AfsX44) which caused an out-of-frame 10-bp insertion. Of these 19 patients, 16 were homozygous for this mutation, which was the most frequent mutation identified in the alleles of the black South African and Cape Coloured patients (96 and 71 %, respectively). CONCLUSION: We recommend that black South African and Cape Coloured patients presenting with cystinosis be tested for CTNS-c.971-12G > A in the first instance, with the possibility of prenatal testing being offered to at-risk families.

Echocardiographic features in Streptococcus agalactiae endocarditis: four cases report.

OBJECTIVE: Streptococcus agalactiae endocarditis is uncommon compared to other types of streptococcal endocarditis. The aim of this study was to describe the echocardiographic features of S. agalactiae endocarditis. MATERIAL AND METHOD: Between January 2010 and December 2012, 150 patients diagnosed with infective endocarditis by the modified Duke criteria treated at Srinagarind Hospital and Queen Sirikit Heart Center, Khon Kaen University were included. The transthoracic echocardiography (TTE) was performed on every patient. RESULTS: Four patients with S. agalactiae endocarditis were identified. The TTE features included one patient with a huge, highly mobile vegetation at the mitral position and patient presented with acute embolic stroke. Two patients with highly mobile vegetations at the aortic position and destroyed aortic cusps, both patients presented with congestive heart failure. One patient with vegetation at mechanical valve, mitral position and patient presented with congestive heart failure. All four patients underwent a combined medical and surgical therapy A correlation between the echocardiographic features and surgical findings in all but two patients, fewer abscesses were found by surgery. CONCLUSION: In the setting of acute endocarditis, the detection of large vegetation and severely destroyed valve by echocardiography is an argument in favor of S. agalactiae endocarditis and may warrant early surgical intervention.

Infective endocarditis in northeastern Thailand.

Despite rigorous diagnostic testing, the cause of infective endocarditis was identified for just 60 (45.5%) of 132 patients admitted to hospitals in Khon Kaen, Thailand, during January 2010-July 2012. Most pathogens identified were Viridans streptococci and zoonotic bacteria species, as found in other resource-limited countries where underlying rheumatic heart disease is common.

Natural Scrub Typhus Antibody Suppresses HIV CXCR4(X4) Viruses.

Viral load generally rises in HIV-infected individuals with a concomitant infection, but falls markedly in some individuals with scrub typhus (ST), a common Asian rickettsial infection. ST infection appears to shift the viral population from CXCR4-using (X4) to CCR5-utilizing (R5) strains, and there is evidence of cross-reactivity between ST-specific antibodies and HIV-1. We examined the mechanism of ST suppression of HIV by measuring the effects of ST infection on X4 and R5 viruses in vivo and in vitro, and assessing the relative contributions of antibodies and chemokines to the inhibitory effect. In vivo, a single scrub typhus plasma infusion markedly reduced the subpopulation of HIV-1 viruses using the X4 co-receptor in all 8 recipients, and eliminated X4 viruses 6 patients. In vitro, the 14 ST sera tested all inhibited the replication of an X4 but not an R5 virus. This inhibitory effect was maintained if ST sera were depleted of chemokines but was lost upon removal of antibodies. Sera from STinfected mice recognized a target that co-localized with X4 HIV gp120 in immunofluorescent experiments. These in vivo and in vitro data suggest that acute ST infection generates cross-reactive antibodies that produce potent suppression of CXCR4- but not CCR5-using HIV-1 viruses. ST suppression of HIV replication could reveal novel mechanisms that could be exploited for vaccination strategies, as well as aid in the development of fusion inhibitors and other new therapeutic regimens. This also appears to be the first instance where one pathogen is neutralized by antibody produced in response to infection by a completely unrelated organism.

Cystine urolithiasis in a caracal (Caracal caracal).

In July 2009, a 14-yr-old male caracal (Caracal caracal) at the National Zoological Gardens of South Africa was found, on abdominal ultrasound, to have a single large cystolith. The cystolith was removed, and the composition was determined to be 100% cystine. Blood and urine samples were also collected from three other apparently healthy caracals at the zoo and were submitted, together with the samples from the affected animal, for analysis using gas chromatograph mass spectrometry for cystine, lysine, alanine, and ornithine levels. The cystine levels in the urine, the fractional excretion of cystine, and the normalized excretion of cystine (micromol/g of creatinine) were all higher in the affected caracal than in the healthy animals. Only a single other case of cystine urolithiasis has been previously reported in any wild felid in the literature.

The first reported cases of Q fever endocarditis in Thailand.

We describe the first two reported cases of Q fever endocarditis in Thailand. Both patients were male, had pre-existing heart valve damage and had contact with cattle. Heightened awareness of Q fever could improve diagnosis and case management and stimulate efforts to identify risk factors and preventive measures.

The first reported case of Bartonella endocarditis in Thailand.

Bartonella species have been shown to cause acute, undifferentiated fever in Thailand. A study to identify causes of endocarditis that were blood culture-negative using routine methods led to the first reported case in Thailand of Bartonella endocarditis A 57 year-old male with underlying rheumatic heart disease presented with severe congestive heart failure and suspected infective endocarditis. The patient underwent aortic and mitral valve replacement. Routine hospital blood cultures were negative but B. henselae was identified by serology, PCR, immunohistochemistry and specific culture techniques.

Glutaric aciduria type 1 in South Africa-high incidence of glutaryl-CoA dehydrogenase deficiency in black South Africans.

Glutaric Aciduria type 1 (GA 1) is an inherited disorder of lysine and tryptophan catabolism that typically manifests in infants with acute cerebral injury associated with intercurrent illness. We investigated the clinical, biochemical and molecular features in 14 known GA 1 patients in South Africa, most of whom were recently confirmed following the implementation of sensitive urine organic acid screening at our laboratory. Age at diagnosis ranged from 3days to 5years and poor clinical outcome reflected the delay in diagnosis in all but one patient. Twelve patients were unrelated black South Africans of whom all those tested (n=11) were found homozygous for the same A293T mutation in the glutaryl-CoA dehydrogenase (GCDH) gene. Excretion of 3-hydroxyglutarate (3-OHGA) was >30.1µmol/mmol creatinine (reference range <2.5) in all cases but glutarate excretion varied with 5 patients considered low excretors (glutarate <50µmol/mmol creatinine). Fibroblast GCDH activity was very low or absent in all of five cases tested. Heterozygosity for the A293T mutation was found 1 in 36 (95% CI; 1/54 - 1/24) unrelated black South African newborns (n=750) giving a predicted prevalence rate for GA 1 of 1 in 5184 (95% CI; 1/11664 - 1/2304) in this population. GA 1 is a treatable but often missed inherited disorder with a previously unrecognised high carrier frequency of a single mutation in the South African black population.