Short tandem repeat expansions in sporadic amyotrophic lateral sclerosis and frontotemporal dementia

Pathogenic short tandem repeat (STR) expansions cause over 20 neurodegenerative diseases. To determine the contribution of STRs in sporadic amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), we used ExpansionHunter, REviewer, and polymerase chain reaction validation to assess 21 neurodegenerative disease-associated STRs in whole-genome sequencing data from 608 patients with sporadic ALS, 68 patients with sporadic FTD, and 4703 matched controls. We also propose a data-derived outlier detection method for defining allele thresholds in rare STRs. Excluding C9orf72 repeat expansions, 17.6% of clinically diagnosed ALS and FTD cases had at least one expanded STR allele reported to be pathogenic or intermediate for another neurodegenerative disease. We identified and validated 162 disease-relevant STR expansions in C9orf72 (ALS/FTD), ATXN1 [spinal cerebellar ataxia type 1 (SCA1)], ATXN2 (SCA2), ATXN8 (SCA8), TBP (SCA17), HTT (Huntington's disease), DMPK [myotonic dystrophy type 1 (DM1)], CNBP (DM2), and FMR1 (fragile-X disorders). Our findings suggest clinical and pathological pleiotropy of neurodegenerative disease genes and highlight their importance in ALS and FTD.

Factors That Influence Non-Motor Impairment Across the ALS-FTD Spectrum: Impact of Phenotype, Sex, Age, Onset and Disease Stage

Objective: This study aimed to establish (1) the pattern and severity of neuropsychiatric symptoms and other non-motor symptoms of sleep and mood, across ALS phenotypes in comparison to bvFTD and (2) the contribution of non-modifiable factors including age, sex and disease state to the severity of symptoms experienced by ALS patients.

Methods: Consecutive participants were recruited to the study and underwent a detailed clinical, cognitive, behavioral and neuroimaging assessment. Neuropsychiatric and other non-motor symptoms were determined using the Cambridge Behavioral Inventory, the CBI-R. The scores were converted to define impairment in terms of mild, moderate and severe symptoms for each subscale. Rate, severity and contribution of King's staging and modifiable factors were also determined and a regression model identified predictors of symptom severity.

Results: In total, 250 participants (115 ALS, 98 bvFTD, and 37 ALS-FTD patients) were recruited. A similar pattern of neuropsychiatric symptom severity was identified (apathy, disinhibition and stereotypic behavior) for all behavioral phenotypes of ALS compared to bvFTD (all p > 0.05). Neuropsychiatric symptoms were also present in cases defined as ALSpure and the cognitive phenotype of ALS (ALSci) although they occurred less frequently and were at the milder end of the spectrum. Disordered sleep and disrupted mood were common across all phenotypes (all p < 0.05). The severity of sleep dysfunction was influenced by both sex and age (all p < 0.05). Neuropsychiatric symptoms, sleep and mood disorders were common early in the disease process and deteriorated in line with progression on the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R; all p < 0.05). Diagnostic phenotype, disease duration and global cognition scores were the strongest predictors of non-motor and neuropsychiatric impairments.

Conclusion: The current findings reveal strikingly similar patterns of changes across the subgroups of ALS and bvFTD, supporting the concept of the ALS-FTD spectrum. The findings further highlight the impact of non-motor and neuropsychiatric symptoms in patients with ALS, that are often as severe as that seen in ALS-FTD and bvFTD. This study advances understanding across the ALS-FTD spectrum that may accelerate the early identification of patient needs, to ensure prompt recognition of symptoms and thereby to improve clinical awareness, patient care and management.

The sinonasal mycobiota in chronic rhinosinusitis and control patients

BACKGROUND

While bacterial associations with chronic rhinosinusitis (CRS) are increasingly well described, fewer studies have examined the fungal component of the sinonasal microbiota. Here we present a study of the sinonasal mycobiota in a cohort of 144 patients (106 patients with CRS and 38 controls).

METHODOLOGY

Fungal communities were characterised by analysis of mucosal swab samples of the left and right middle meatuses via ITS2 marker amplicon sequencing on the Illumina MiSeq platform. Fungal associations with previously published bacterial community and inflammatory cytokine and cell data for this cohort (collected at the same intra-operative time point) were also investigated.

RESULTS

Malassezia spp. were ubiquitous and often highly predominant. Season of sampling explained more of the variability in the data than any of the clinical parameters. The predominant Malassezia sp. was distinct in patients with cystic fibrosis compared to those without. However, distinctions in the mycobiota were not evident between any other patient groupings assessed, and few fungal-bacterial or fungal-inflammatory associations were observed.

CONCLUSIONS

This study confirms the prominent place of Malassezia spp. within the upper respiratory tract. Overall, few distinctions between patient groups were evident, and these data lend further support to the hypothesis that fungal community types may have no direct causative association with idiopathic CRS. Additional studies incorporating a broader array of inflammatory markers are required to assess whether these ubiquitous fungi nonetheless play an exacerbating role in some sensitive individuals.

015 Unravelling psychosis in motor neurone disease – a study of clinical features, cognition, and survival

Introduction

Psychotic symptoms are now recognised to occur in patients with MND, often in association with FTD, and particularly in C9orf72 expansion carriers. As yet the impact of these symptoms on the clinical disease state is unknown and the relationship between severity and nature of these symptoms is not well understood. This study aimed to comprehensively explore the relationship between psychotic symptoms, clinical features, cognitive status and survival.

Methods

In total 148 participants; MND (n=100) and MND-FTD (n=48), were enrolled in the study. A detailed clinical interview in addition to a neurological, neuropsychological and behavioural assessment, genetic testing and brain MRI was undertaken in each participant

Results

Psychotic symptoms were present in 25% of the cohort. The majority of participants in the psychosis cohort were male (83%) and were negative for the C9orf72 expansion (70%). Psychotic symptoms in younger patients were more likely to be florid, require medication and delay diagnosis. Within the MND subgroup, patients with psychotic symptoms were more impaired in the cognitive subdomains of attention, memory and executive functioning and exhibited more disinhibition, apathy and stereotypy, than patients without psychotic symptoms (all p<0.01), but no differences were identified for the MND-FTD subgroup (all p>0.2). Symptoms of depression were more common in those without psychotic symptoms (p>0.1). Survival was prolonged for patients with psychotic symptoms (HR=4.7, 95% CI: 2.1–10, p<0.001)

Conclusion

MND with psychosis represents a distinct clinical, cognitive and behavioural phenotype that has a positive impact on survival and may represent an overlap with psychiatric disorders.

Eating peptides: biomarkers of neurodegeneration in amyotrophic lateral sclerosis and frontotemporal dementia

Objective

Physiological changes potentially influence disease progression and survival along the Amyotrophic Lateral Sclerosis (ALS)-Frontotemporal dementia (FTD) spectrum. The peripheral peptides that regulate eating and metabolism may provide diagnostic, metabolic, and progression biomarkers. The current study aimed to examine the relationships and biomarker potential of hormonal peptides.

Methods

One hundred and twenty-seven participants (36 ALS, 26 ALS- cognitive, patients with additional cognitive behavioral features, and 35 behavioral variant FTD (bvFTD) and 30 controls) underwent fasting blood analyses of leptin, ghrelin, neuropeptide Y (NPY), peptide YY (PYY), and insulin levels. Relationships between endocrine measures, cognition, eating behaviors, and body mass index (BMI) were investigated. Biomarker potential was evaluated using multinomial logistic regression for diagnosis and correlation to disease duration.

Results

Compared to controls, ALS and ALS-cognitive had higher NPY levels and bvFTD had lower NPY levels, while leptin levels were increased in all patient groups. All groups had increased insulin levels and a state of insulin resistance compared to controls. Lower NPY levels correlated with increasing eating behavioral change and BMI, while leptin levels correlated with BMI. On multinomial logistic regression, NPY and leptin levels were found to differentiate between diagnosis. Reduced Neuropeptide Y levels correlated with increasing disease duration, suggesting it may be useful as a potential marker of disease progression.

Interpretation

ALS-FTD is characterized by changes in NPY and leptin levels that may impact on the underlying regional neurodegeneration as they were predictive of diagnosis and disease duration, offering the potential as biomarkers and for the development of interventional treatments.

Lipid Metabolism and Survival Across the Frontotemporal Dementia-Amyotrophic Lateral Sclerosis Spectrum: Relationships to Eating Behavior and Cognition

BACKGROUND

Patients with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) exhibit changes in eating behavior that could potentially affect lipid levels.

OBJECTIVE

This study aimed to document changes in lipid metabolism across the ALS-FTD spectrum to identify potential relationships to eating behavior (including fat intake), cognitive change, body mass index (BMI), and effect on survival.

METHODS

One hundred and twenty-eight participants were recruited: 37 ALS patients, 15 ALS patients with cognitive and behavioral change (ALS-Plus), 13 ALS-FTD, 31 behavioral variant FTD, and 32 healthy controls. Fasting total cholesterol, low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL) and triglyceride levels were measured and correlated to eating behavior (caloric, fat intake), cognitive change, and BMI; effect on survival was examined using cox regression analyses.

RESULTS

There was a spectrum of lipid changes from ALS to FTD with increased triglyceride (p < 0.001), total cholesterol/HDL ratio (p < 0.001), and lower HDL levels (p = 0.001) in all patient groups compared to controls. While there was no increase in total cholesterol levels, a higher cholesterol level was found to correlate with 3.25 times improved survival (p = 0.008). Triglyceride and HDL cholesterol levels correlated to fat intake, BMI, and measures of cognition and disease duration.

CONCLUSION

A spectrum of changes in lipid metabolism has been identified in ALS-FTD, with total cholesterol levels found to potentially impact on survival. These changes were mediated by changes in fat intake, and BMI, and may also be mediated by the neurodegenerative process, offering the potential to modify these factors to slow disease progression and improve survival.

013 Lipid metabolism and body composition in frontotemporal dementia-amyotrophic lateral sclerosis spectrum: effect on survival and disease progression

Introduction

Patients with Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) exhibit changes in eating behaviour that could potentially affect lipid levels and body composition. This study aimed to document changes in lipid metabolism and body composition across the ALS-FTD spectrum to identify potential relationships to eating behaviour (including fat intake), cognitive change, body mass index (BMI) and effect on survival.

Methods

One hundred and twenty eight participants were recruited: 37 ALS patients, 15 ALS patients with cognitive and behavioural change (ALS-Plus), and 13 ALS-FTD, 31 behavioural variant FTD, and 32 healthy controls. Fasting total cholesterol, low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL) and triglyceride levels were measured and correlated to eating behaviour (caloric, fat intake), cognitive change, and BMI; effect on survival was examined using cox regression analyses. In a cohort of 60 patients, changes in body composition and fat deposition was examined using Dual energy X-ray absorptiometry scans (DEXA), a technique used in obesity research.

Results

There was a spectrum of lipid changes from ALS to FTD with increased triglyceride (p<0.001), total cholesterol/HDL ratio (p<0.001), and lower HDL levels (p=0.001) in all patient groups compared to controls. Whilst there was no increase in total cholesterol levels, a higher cholesterol level was found to correlate with 3.25 times improved survival (p=0.031). Triglyceride and HDL cholesterol correlated to fat intake, BMI, and measures of cognition and

Conclusion

A spectrum of changes in lipid metabolism and body composition has been identified in ALS-FTD, with total cholesterol levels found to potentially impact on survival. These changes were mediated by changes in fat intake, and BMI, and may also be mediated by the neurodegenerative process, offering the potential to modify these factors to slow disease progression and improve survival.

Motor neurone disease - caring for the patient in general practice

BACKGROUND

Motor neurone disease is a neurodegenerative disease that leads to progressive disability - and eventually death - within 2-3 years.

OBJECTIVE

This article describes the role of the general practitioner in caring for patients with motor neurone disease.

DISCUSSION

The diagnosis of motor neurone disease relies on the presence of upper and lower motor neurone features. There is currently no pathognomic test for motor neurone disease and it largely remains a diagnosis of exclusion following an accurate clinical history, combined with basic screening blood investigations and structural imaging of the brain and spinal cord. Neuro-physiological studies may be useful as an ancillary diagnostic tool. Riluzole, an anti-glutamate agent, is the only medication shown to have a survival benefit in motor neurone disease and results in a slowing of disease progression by an estimated 3-6 months. Noninvasive ventilation may relieve symptoms related to respiratory insufficiency and prolong survival by up to 12 months. A multidisciplinary approach to management has been shown to improve the quality of life for patients as well as survival. The GP is often the first point-of contact when medical issues arise regarding management of disease related symptoms including sialorrhoea, dyspnoea, constipation and pain, through to percutaneous gastrostomy feeding tubes and maintenance of noninvasive ventilation. It is important to establish the patient's wishes for future care while they are still able to communicate easily.