A mitochondrial cytopathy presenting with persistent troponin elevation: case report.

Background: Mitochondrial diseases represent an important potential cause of cardiomyopathy and should be considered in patients presenting with multisystem manifestations. Timely diagnosis of a mitochondrial disorder is needed as it can have reproductive implications for the offspring of the proband. Case Summary: We describe a case of undifferentiated rising and persistent troponin elevation in a 70-year-old female with only mild heart failure symptoms and signs. An eventual diagnosis of a mitochondrial cytopathy was made after genetic testing, striated muscle, and endomyocardial biopsy. Multidisciplinary involvement was vital in securing the ultimate diagnosis and is a key lesson from this case. On follow up, with institution of heart failure therapy including cardiac resynchronisation device therapy there was improvement in exercise tolerance and symptoms. Discussion: For discussion is the investigation of undifferentiated cardiomyopathies and consideration of mitochondrial disorders as an important diagnosis to exclude prior to diagnosis as an idiopathic cardiomyopathy.

Association between DNA methylation variability and self-reported exposure to heavy metals.

Individuals encounter varying environmental exposures throughout their lifetimes. Some exposures such as smoking are readily observed and have high personal recall; others are more indirect or sporadic and might only be inferred from long occupational histories or lifestyles. We evaluated the utility of using lifetime-long self-reported exposures for identifying differential methylation in an amyotrophic lateral sclerosis cases-control cohort of 855 individuals. Individuals submitted paper-based surveys on exposure and occupational histories as well as whole blood samples. Genome-wide DNA methylation levels were quantified using the Illumina Infinium Human Methylation450 array. We analyzed 15 environmental exposures using the OSCA software linear and MOA models, where we regressed exposures individually by methylation adjusted for batch effects and disease status as well as predicted scores for age, sex, cell count, and smoking status. We also regressed on the first principal components on clustered environmental exposures to detect DNA methylation changes associated with a more generalised definition of environmental exposure. Five DNA methylation probes across three environmental exposures (cadmium, mercury and metalwork) were significantly associated using the MOA models and seven through the linear models, with one additionally across a principal component representing chemical exposures. Methylome-wide significance for four of these markers was driven by extreme hyper/hypo-methylation in small numbers of individuals. The results indicate the potential for using self-reported exposure histories in detecting DNA methylation changes in response to the environment, but also highlight the confounded nature of environmental exposure in cohort studies.

NEK1 and STMN2 short tandem repeat lengths are not associated with Australian amyotrophic lateral sclerosis risk.

Sporadic amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a complex genetic architecture. The lengths of two short tandem repeats (STRs), at the NEK1 and STMN2 loci, were recently associated with ALS risk in cohorts of European descent. The STMN2 STR was proposed to be predictive of clinical features including the age of onset and disease duration in bulbar onset cases. We sought to investigate NEK1 and STMN2 STR lengths in a cohort of Australian sporadic ALS cases (n = 608) and neurologically healthy controls (n = 4689) of European ancestry. ExpansionHunter was used to determine NEK1 and STMN2 STR length genotypes from whole-genome sequencing data followed by PCR validation of predicted lengths. No significant association was identified between sporadic ALS risk and the length of either STR. Further, neither NEK1 nor STMN2 STR lengths were indicative of the age of onset or disease duration. We report that the NEK1 and STMN2 STRs were not associated with ALS risk or clinical features in this Australian sporadic ALS cohort.

The prevalence of inorganic mercury in human cells increases during aging but decreases in the very old.

Successful aging is likely to involve both genetic and environmental factors, but environmental toxicants that accelerate aging are not known. Human exposure to mercury is common, and mercury has genotoxic, autoimmune, and free radical effects which could contribute to age-related disorders. The presence of inorganic mercury was therefore assessed in the organs of 170 people aged 1-104 years to determine the prevalence of mercury in human tissues at different ages. Mercury was found commonly in cells of the brain, kidney, thyroid, anterior pituitary, adrenal medulla and pancreas. The prevalence of mercury in these organs increased during aging but decreased in people aged over 80 years. People with mercury in one organ usually also had mercury in several others. In conclusion, the prevalence of inorganic mercury in human organs increases with age. The relative lack of tissue mercury in the very old could account for the flattened mortality rate and reduced incidence of cancer in this advanced age group. Since mercury may accelerate aging, efforts to reduce atmospheric mercury pollution could improve the chances of future successful aging.

The Prevalence of Inorganic Mercury in Human Kidneys Suggests a Role for Toxic Metals in Essential Hypertension.

The kidney plays a dominant role in the pathogenesis of essential hypertension, but the initial pathogenic events in the kidney leading to hypertension are not known. Exposure to mercury has been linked to many diseases including hypertension in epidemiological and experimental studies, so we studied the distribution and prevalence of mercury in the human kidney. Paraffin sections of kidneys were available from 129 people ranging in age from 1 to 104 years who had forensic/coronial autopsies. One individual had injected himself with metallic mercury, the other 128 were from varied clinicopathological backgrounds without known exposure to mercury. Sections were stained for inorganic mercury using autometallography. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used on six samples to confirm the presence of autometallography-detected mercury and to look for other toxic metals. In the 128 people without known mercury exposure, mercury was found in: (1) proximal tubules of the cortex and Henle thin loops of the medulla, in 25% of kidneys (and also in the man who injected himself with mercury), (2) proximal tubules only in 16% of kidneys, and (3) Henle thin loops only in 23% of kidneys. The age-related proportion of people who had any mercury in their kidney was 0% at 1-20 years, 66% at 21-40 years, 77% at 41-60 years, 84% at 61-80 years, and 64% at 81-104 years. LA-ICP-MS confirmed the presence of mercury in samples staining with autometallography and showed cadmium, lead, iron, nickel, and silver in some kidneys. In conclusion, mercury is found commonly in the adult human kidney, where it appears to accumulate in proximal tubules and Henle thin loops until an advanced age. Dysfunctions of both these cortical and medullary regions have been implicated in the pathogenesis of essential hypertension, so these findings suggest that further studies of the effects of mercury on blood pressure are warranted.

Mercury in the human thyroid gland: Potential implications for thyroid cancer, autoimmune thyroiditis, and hypothyroidism.

OBJECTIVE: Mercury and other toxic metals have been suggested to be involved in thyroid disorders, but the distribution and prevalence of mercury in the human thyroid gland is not known. We therefore used two elemental bio-imaging techniques to look at the distribution of mercury and other toxic metals in the thyroid glands of people over a wide range of ages. MATERIALS AND METHODS: Formalin-fixed paraffin-embedded thyroid tissue blocks were obtained from 115 people aged 1-104 years old, with varied clinicopathological conditions, who had thyroid samples removed during forensic/coronial autopsies. Seven-micron sections from these tissue blocks were used to detect intracellular inorganic mercury using autometallography. The presence of mercury was confirmed using laser ablation-inductively coupled plasma-mass spectrometry which can detect multiple elements. RESULTS: Mercury was found on autometallography in the thyroid follicular cells of 4% of people aged 1-29 years, 9% aged 30-59 years, and 38% aged 60-104 years. Laser ablation-inductively coupled plasma-mass spectrometry confirmed the presence of mercury in samples staining with autometallography, and detected cadmium, lead, iron, nickel and silver in selected samples. CONCLUSIONS: The proportion of people with mercury in their thyroid follicular cells increases with age, until it is present in over one-third of people aged 60 years and over. Other toxic metals in thyroid cells could enhance mercury toxicity. Mercury can trigger genotoxicity, autoimmune reactions, and oxidative damage, which raises the possibility that mercury could play a role in the pathogenesis of thyroid cancers, autoimmune thyroiditis, and hypothyroidism.

Mercury in Pancreatic Cells of People with and without Pancreatic Cancer.

Toxic metals have been implicated in the pathogenesis of pancreatic cancer. Human exposure to mercury is widespread, but it is not known how often mercury is present in the human pancreas and which cells might contain mercury. We therefore aimed to determine, in people with and without pancreatic cancer, the distribution and prevalence of mercury in pancreatic cells. Paraffin-embedded sections of normal pancreatic tissue were obtained from pancreatectomy samples of 45 people who had pancreatic adenocarcinoma, and from autopsy samples of 38 people without pancreatic cancer. Mercury was identified using two methods of elemental bio-imaging: (1) With autometallography, inorganic mercury was seen in islet cells in 14 of 30 males (47%) with pancreatic cancer compared to two of 17 males (12%) without pancreatic cancer (p = 0.024), and in 10 of 15 females (67%) with pancreatic cancer compared to four of 22 females (19%) without pancreatic cancer (p = 0.006). Autometallographic mercury was present in acinar cells in 24% and in periductal cells in 11% of people with pancreatic cancer, but not in those without pancreatic cancer. (2) Laser ablation-inductively coupled plasma-mass spectrometry confirmed the presence of mercury in islets that stained with autometallography and detected cadmium, lead, chromium, iron, nickel and aluminium in some samples. In conclusion, the genotoxic metal mercury is found in normal pancreatic cells in more people with, than without, pancreatic cancer. These findings support the hypothesis that toxic metals such as mercury contribute to the pathogenesis of pancreatic cancer.

Elemental bioimaging shows mercury and other toxic metals in normal breast tissue and in breast cancers.

OBJECTIVE: Exposure to toxic metals such as mercury has been proposed to be a risk factor for the development of breast cancer since some metals can promote genetic mutations and epigenetic changes. We sought to find what toxic metals are present in normal breast tissue and in the tumours of women who had mastectomies for invasive ductal breast carcinoma. MATERIALS AND METHODS: Formalin-fixed paraffin-embedded blocks from mastectomies for breast carcinoma were examined from 50 women aged 34-69 years. Paraffin blocks selected for elemental analysis were from breast tissue not involved by carcinoma and from the carcinoma itself. Seven micrometer-thick sections were stained with autometallography to demonstrate the presence of mercury, and subjected to laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to confirm the presence of mercury and to detect other toxic metals. RESULTS: Autometallography-detected mercury was seen in intraductal secretions and some luminal epithelial cells of normal breast lobules in 26 (55%) of the 47 samples where lobules were present, and in 10 (23%) of carcinomas from the 44 samples where carcinoma was present. In eight samples ductal carcinoma in situ was present and one of these contained mercury. LA-ICP-MS confirmed the presence of mercury in samples that stained with autometallography, and detected lead, iron, nickel, aluminium, chromium and cadmium in some samples. CONCLUSIONS: Mercury was present in normal breast lobules in more than half of mastectomy samples that contained an invasive carcinoma, and in a smaller proportion of carcinomas and ductal carcinomas in situ. Other toxic metals that may interact synergistically with mercury could be detected in some samples. These findings do not provide direct evidence that toxic metals such as mercury play a role in the pathogenesis of breast cancer, but suggest that future molecular biological investigations on the role of toxic metals in breast cancer are warranted.

Anncaliia algerae Microsporidial Myositis, New South Wales, Australia.

We describe the successful management of Anncaliia algerae microsporidial myositis in a man with graft versus host disease after hemopoietic stem cell transplantation. We also summarize clinical presentation and management approaches and discuss the importance of research into the acquisition of this infection and strategies for prevention.

Inorganic mercury in human astrocytes, oligodendrocytes, corticomotoneurons and the locus ceruleus: implications for multiple sclerosis, neurodegenerative disorders and gliomas.

Neurotoxic metals have been implicated in the pathogenesis of multiple sclerosis, neurodegenerative disorders and brain tumours but studies of the location of heavy metals in human brains are rare. In a man who injected himself with metallic mercury the cellular location of mercury in his brain was studied after 5 months of continuous exposure to inorganic mercury arising from metallic mercury deposits in his organs. Paraffin sections from the primary motor and sensory cortices and the locus ceruleus in the pons were stained with autometallography to detect inorganic mercury and combined with glial fibrillary acidic protein immunohistochemistry to identify astrocytes. Inorganic mercury was found in grey matter subpial, interlaminar, protoplasmic and varicose astrocytes, white matter fibrous astrocytes, grey but not white matter oligodendrocytes, corticomotoneurons and some locus ceruleus neurons. In summary, inorganic mercury is taken up by five types of human brain astrocytes, as well as by cortical oligodendrocytes, corticomotoneurons and locus ceruleus neurons. Mercury can induce oxidative stress, stimulate autoimmunity and damage DNA, mitochondria and lipid membranes, so its location in these CNS cells suggests it could play a role in the pathogenesis of multiple sclerosis, neurodegenerative conditions such as Alzheimer's disease and amyotrophic lateral sclerosis, and glial tumours.

Whole genome analyses reveal no pathogenetic single nucleotide or structural differences between monozygotic twins discordant for amyotrophic lateral sclerosis.

The contribution of genetic and environmental factors to the pathogenesis of sporadic amyotrophic lateral sclerosis (ALS) remains unclear. To investigate the genetic component of the disease, we performed whole genome sequencing on ALS discordant monozygotic twins. Illumina whole genome sequencing on white blood cell DNA of five ALS-discordant monozygotic twin pairs (10 samples in total) yielded ∼30x coverage per individual. All single nucleotide variants, indels, and structural variants (copy number variants, inversions and translocations) were called and evaluated for functional consequence, evolutionary conservation, population frequency and overlap with known ALS associated variants and genes. Results showed that no validated discordant coding or regulatory single nucleotide variants or indels were found, and nor were any genome-wide discordant structural variants detected. Concordant variants of particular interest were: 1) two rare, highly-conserved heterozygous non-synonymous variants in SYT9 and EWSR1, genes previously associated with ALS (out of 2044 rare heterozygous variants detected); 2) three rare homozygous missense variants; and 3) three novel copy number deletions that overlapped genes. In conclusion, no convincing coding or regulatory nucleotide or genome-wide structural differences were found between ALS discordant monozygotic twins. The results suggest that more work is needed to elucidate possible environmental, epigenetic, oligogenic and somatic genetic factors that could underlie susceptibility to sporadic ALS.

Is the risk of motor neuron disease increased or decreased after cancer? An Australian case-control study.

Cancer appears to be inversely associated with both Alzheimer's and Parkinson's disease. The relationship between cancer and sporadic motor neuron disease (SMND), however, remains uncertain. Most previous cancer-SMND studies have been undertaken in northern hemisphere populations. We therefore undertook a case-control study to see if a link between cancer and SMND exists in an Australian population. A questionnaire was used to compare past cancer diagnoses in 739 SMND patients and 622 controls, recruited across Australia. Odds ratios with 95% confidence intervals were calculated to look for associations between cancer and SMND. A history of cancer was not associated either positively or negatively with a risk of subsequent SMND. This result remained when age, gender, smoking status, and the four SMND diagnostic subgroups were taken into account. No association was observed between SMND and specific tumours, including melanoma, a common malignancy in Australia. In conclusion, this Australian case-control study does not support an association between a past history of cancer and the development of SMND. This suggests that some pathogenetic mechanisms, such as apoptosis, are less relevant in SMND than in other neurodegenerative diseases where negative associations with cancer have been found.

Unusual clinical and molecular-pathological profile of gerstmann-Sträussler-Scheinker disease associated with a novel PRNP mutation (V176G).

IMPORTANCE: Here we describe the unusual clinical and molecular-neuropathological profile of a case of Gerstmann-Sträussler-Scheinker disease associated with a novel prion protein (PRNP) gene mutation. OBSERVATIONS: This case report from the Australian National Creutzfeldt-Jakob Disease Registry concerns a 61-year-old British-born woman with no history of neurodegenerative disorder in first-degree relatives. Rapidly progressive dementia, altered behavior, and cerebellar ataxia dominated the clinical picture in the period immediately following minor elective surgery, with death 1 month later in an akinetic-mute state. Brain histopathological examination revealed neuronal loss, scant foci of spongiform change, and diffuse multicentric amyloid plaques, selectively immunoreactive for prion protein, within the cerebral and cerebellar cortices and deep gray matter. Tau immune-reactive neurofibrillary tangles and neuritic threads were present in the cerebral cortex. PRNP sequencing demonstrated a valine to glycine mutation at codon 176, with valine homozygosity at polymorphic codon 129. Western-blot analysis of frozen brain tissue displayed a nonclassic protease-resistant prion protein banding pattern, with a prominent approximately 8-kDa protease-resistant fragment. CONCLUSIONS AND RELEVANCE: Reported is a proband with a novel PRNP mutation associated with neuropathologically confirmed Gerstmann-Sträussler-Scheinker disease displaying a somewhat unusual constellation of clinicopathological features, which overall subserve to further broaden an already diverse phenotypic spectrum.

Smoking is not a risk factor for sporadic amyotrophic lateral sclerosis in an Australian population.

BACKGROUND: Controversy persists as to whether smoking is a risk factor for sporadic amyotrophic lateral sclerosis (SALS), the most common form of sporadic motor neuron disease (SMND). We therefore undertook a large case-control study of smoking and SALS in Australia. METHODS: Cases and controls were recruited Australia-wide over a 10-year period. SALS and the other subgroups of SMND were categorised on the basis of neurologists' reports. Controls were partners or friends of SMND patients or community volunteers. Individuals filled in a questionnaire regarding smoking habits. A total of 809 patients with SMND (631 with SALS) and 779 controls were included in the study. SALS males and females were analysed separately. RESULTS: No differences between SALS patients and control groups were found with regard to (1) the odds ratios of ever-smokers, ex-smokers or current smokers compared to never-smokers, (2) the means of numbers of cigarettes per day, years of smoking, pack years or age smoking began or (3) the proportions of their parents who had ever smoked. The proportion of ever-smokers and mean pack years did not differ between the clinical subgroups of SMND or between different sites of SALS onset. Partner smoking did not increase the risk of SMND. CONCLUSION: This Australian case-control study does not support a link between cigarette smoking and any form of SMND.

Overview and recent advances in neuropathology. Part 2: Neurodegeneration.

The sections in the following review cover six main neurodegenerative diseases. The first article on Alzheimer's disease (AD) outlines the major evidence available to date that links Aß-amyloid peptide as a proximal cause of AD. The article also highlights how an initial finding of the protein content of the amyloid plaque seen in the brains of patients with AD has led to many very significant findings in the neuroscience field. The next section outlines the many and recent advances that have occurred in the field of frontotemporal lobar degeneration (FTLD), including the most recent finding related to the fused sarcoma gene (FUS) and the newest nomenclature whereby the FTLD is subtyped according to the presence of specific proteins seen at a microscopic level. The section on Lewy bodies outlines the latest advances in the relationship between the anatomical distribution of Lewy bodies and disease phenotype. The following section includes an overview of current known genetic links with familial causes of motor neuron disease (MND) and an update on the areas being researched into the causes of sporadic MND. The presence of TDP-43 within inclusions and its new diagnostic role in MND are discussed. The final article on prion diseases gives an overview of human prion diseases, including the phenotypic spectrum, epidemiology and diagnostic investigations relevant to disease.

What lies beneath the tent? JC-virus cerebellar granule cell neuronopathy complicating sarcoidosis.

A 49-year-old, HIV-negative woman with sarcoidosis presented with a subacute unilateral cerebellar syndrome. A brain MRI revealed a hyperintense lesion without mass effect in the left cerebellar hemisphere, but no pathology above the tentorium. Steroid therapy for presumed neurosarcoidosis was ineffective and the patient deteriorated progressively. Cerebellar biopsy showed abnormal granule cells and demyelination. Immunocytochemistry confirmed the diagnosis of progressive multifocal leucoencephalopathy (PML) with JC (John Cunningham) virus granule cell neuronopathy. The patient succumbed to progressive brainstem dysfunction despite treatment with cidofovir. Although rare, PML should be considered in all patients with impaired cell-mediated immunity and unexplained neurological dysfunction, even in the absence of HIV infection.

An epigenetic analysis of SOD1 and VEGF in ALS.

Epigenetic silencing of a gene vital for motor neuron function could underlie sporadic ALS. We therefore examined the methylation status of two genes, SOD1 and VEGF, which are implicated in ALS. Methylation in the promoters of these genes was determined in white cell DNA (10 ALS patients) and brain DNA (six ALS patients). The promoter regions were largely unmethylated in all patients. Transcriptional silencing of these genes is therefore unlikely to be a common mechanism in ALS. However, in view of the potential for treatment of epigenetic disorders, promoter methylation in other genes required for motor neuron survival needs to be studied.

Are enteroviral receptors different in sporadic motor neuron disease?

Enteroviruses have been suspected to play a part in the pathogenesis of sporadic motor neuron disease (SMND). Intercellular adhesion molecule type-1 (ICAM1) and coxsackie and adenovirus receptor (CAR) act as receptors for a number of enteroviruses. We therefore examined the viral binding domains of ICAM1 and CAR to see if any changes could be found that might predispose to enteroviral infections. Single nucleotide polymorphisms in the ICAM1 viral binding domain, the adjacent intron and a region implicated in other neurological disorders, as well as the CAR viral binding regions in exons 2-5, were compared in 139 SMND patients and 139 matched controls. The distribution of the polymorphisms was similar in both groups. Therefore, based on linkage disequilibrium and genotype it is unlikely that either ICAM1 or CAR is implicated in SMND.

A gene-environment study of the paraoxonase 1 gene and pesticides in amyotrophic lateral sclerosis.

Sporadic amyotrophic lateral sclerosis (SALS) causes progressive muscle weakness because of the loss of motor neurons. SALS has been associated with exposure to environmental toxins, including pesticides and chemical warfare agents, many of which are organophosphates. The enzyme paraoxonase 1 (PON1) detoxifies organophosphates and the efficacy of this enzyme varies with polymorphisms in the PON1 gene. To determine if an impaired ability to break down organophosphates underlies some cases of SALS, we compared the frequencies of PON1 polymorphisms in SALS patients and controls and investigated gene-environment interactions with self-reported pesticide/herbicide exposure. The PON1 coding polymorphisms L55M, Q192R and I102V, and the promoter polymorphisms -909c>g, -832g>a, -162g>a and -108c>t, were genotyped in 143 SALS patients and 143 matched controls. Statistical comparisons were carried out at allele, genotype and haplotype levels. The PON1 promoter allele -108t, which reduces PON1 expression, was strongly associated with SALS. Overall, promoter haplotypes that decrease PON1 expression were associated with SALS, whereas haplotypes that increase expression were associated with controls. Coding polymorphisms did not correlate with SALS. Gene-environment interactions were identified at the allele level for some promoter SNPs and pesticide/herbicide exposure, but not at the genotype or haplotype level. In conclusion, some PON1 promoter polymorphisms may predispose to SALS, possibly by making motor neurons more susceptible to organophosphate-containing toxins.