Skin Biopsy Detection of Phosphorylated α-Synuclein in Patients With Synucleinopathies.

Importance: Finding a reliable diagnostic biomarker for the disorders collectively known as synucleinopathies (Parkinson disease [PD], dementia with Lewy bodies [DLB], multiple system atrophy [MSA], and pure autonomic failure [PAF]) is an urgent unmet need. Immunohistochemical detection of cutaneous phosphorylated α-synuclein may be a sensitive and specific clinical test for the diagnosis of synucleinopathies. Objective: To evaluate the positivity rate of cutaneous α-synuclein deposition in patients with PD, DLB, MSA, and PAF. Design, Setting, and Participants: This blinded, 30-site, cross-sectional study of academic and community-based neurology practices conducted from February 2021 through March 2023 included patients aged 40 to 99 years with a clinical diagnosis of PD, DLB, MSA, or PAF based on clinical consensus criteria and confirmed by an expert review panel and control participants aged 40 to 99 years with no history of examination findings or symptoms suggestive of a synucleinopathy or neurodegenerative disease. All participants completed detailed neurologic examinations and disease-specific questionnaires and underwent skin biopsy for detection of phosphorylated α-synuclein. An expert review panel blinded to pathologic data determined the final participant diagnosis. Exposure: Skin biopsy for detection of phosphorylated α-synuclein. Main Outcomes: Rates of detection of cutaneous α-synuclein in patients with PD, MSA, DLB, and PAF and controls without synucleinopathy. Results: Of 428 enrolled participants, 343 were included in the primary analysis (mean [SD] age, 69.5 [9.1] years; 175 [51.0%] male); 223 met the consensus criteria for a synucleinopathy and 120 met criteria as controls after expert panel review. The proportions of individuals with cutaneous phosphorylated α-synuclein detected by skin biopsy were 92.7% (89 of 96) with PD, 98.2% (54 of 55) with MSA, 96.0% (48 of 50) with DLB, and 100% (22 of 22) with PAF; 3.3% (4 of 120) of controls had cutaneous phosphorylated α-synuclein detected. Conclusions and Relevance: In this cross-sectional study, a high proportion of individuals meeting clinical consensus criteria for PD, DLB, MSA, and PAF had phosphorylated α-synuclein detected by skin biopsy. Further research is needed in unselected clinical populations to externally validate the findings and fully characterize the potential role of skin biopsy detection of phosphorylated α-synuclein in clinical care.

Unveiling autonomic failure in synucleinopathies: Significance in diagnosis and treatment.

Autonomic failure is frequently encountered in synucleinopathies such as multiple system atrophy (MSA), Parkinson's disease (PD), Lewy body disease, and pure autonomic failure (PAF). Cardiovascular autonomic failure affects quality of life and can be life threatening due to the risk of falls and the increased incidence of myocardial infarction, stroke, and heart failure. In PD and PAF, pathogenic involvement is mainly post-ganglionic, while in MSA, the involvement is mainly pre-ganglionic. Cardiovascular tests exploring the autonomic nervous system (ANS) are based on the analysis of continuous, non-invasive recordings of heart rate and digital blood pressure (BP). They assess facets of sympathetic and parasympathetic activities and provide indications on the integrity of the baroreflex arc. The tilt test is widely used in clinical practice. It can be combined with catecholamine level measurement and analysis of baroreflex activity and cardiac variability for a detailed analysis of cardiovascular damage. MIBG myocardial scintigraphy is the most sensitive test for early detection of autonomic dysfunction. It provides a useful measure of post-ganglionic sympathetic fiber integrity and function and is therefore an effective tool for distinguishing PD from other parkinsonian syndromes such as MSA. Autonomic cardiovascular investigations differentiate between certain parkinsonian syndromes that would otherwise be difficult to segregate, particularly in the early stages of the disease. Exploring autonomic failure by gathering information about residual sympathetic tone, low plasma norepinephrine levels, and supine hypertension can guide therapeutic management of orthostatic hypotension (OH).

An overview on pure autonomic failure.

Pure autonomic failure (PAF) is a neurodegenerative disease affecting the sympathetic component of the autonomic nervous system and presenting as orthostatic hypotension (OH). It is a rare, sporadic disease of adults. Although OH is the primary symptom, the autonomic dysfunction may be more generalised, leading to genitourinary and intestinal dysfunction and sweating disorders. Autonomic symptoms in PAF may be similar to those observed in other autonomic neuropathies that need to be ruled out. PAF belongs to the group of α synucleinopathies and is characterised by predominant peripheral deposition of α-synuclein in autonomic ganglia and nerves. However, in a significant number of cases, PAF may convert into another synucleinopathy with central nervous system involvement with varying prognosis: Parkinson's disease (PD), multiple system atrophy (MSA), or dementia with Lewy bodies (DLB). The clinical features, the main differential diagnoses, the risk factors for "phenoconversion" to another synucleinopathy as well as an overview of treatment will be discussed.

Diagnosing Premotor Multiple System Atrophy: Natural History and Autonomic Testing in an Autopsy-Confirmed Cohort.

BACKGROUND AND OBJECTIVES: Nonmotor features precede motor symptoms in many patients with multiple system atrophy (MSA). However, little is known about differences between the natural history, progression, and prognostic factors for survival in patients with MSA with nonmotor vs motor presentations. We aimed to compare initial symptoms, disease progression, and clinical features at final evaluation and investigate differences in survival and natural history between patients with MSA with motor and nonmotor presentations. METHODS: Medical records of autopsy-confirmed MSA cases at Queen Square Brain Bank who underwent both clinical examination and cardiovascular autonomic testing were identified. Clinical features, age at onset, sex, time from onset to diagnosis, disease duration, autonomic function tests, and plasma noradrenaline levels were evaluated. RESULTS: Forty-seven patients with autopsy-confirmed MSA (age 60 ± 8 years; 28 men) were identified. Time from symptom onset to first autonomic evaluation was 4 ± 2 years, and the disease duration was 7.7 ± 2.2 years. Fifteen (32%) patients presented with nonmotor features including genitourinary dysfunction, orthostatic hypotension, or REM sleep behavior disorder before developing motor involvement (median delay 1-6 years). A third (5/15) were initially diagnosed with pure autonomic failure (PAF) before evolving into MSA. All these patients had normal supine plasma noradrenaline levels (332.0 ± 120.3 pg/mL) with no rise on head-up tilt (0.1 ± 0.3 pg/mL). Patients with MSA with early cardiovascular autonomic dysfunction (within 3 years of symptom onset) had shorter survival compared with those with later onset of cardiovascular autonomic impairment (6.8 years [5.6-7.9] vs 8.5 years [7.9-9.2]; p = 0.026). Patients with early urinary catheterization had shorter survival than those requiring catheterization later (6.2 years [4.6-7.8] vs 8.5 years [7.6-9.4]; p = 0.02). The survival of patients with MSA presenting with motor and nonmotor symptoms did not differ (p > 0.05). DISCUSSION: Almost one-third of patients with MSA presented with nonmotor features, which could predate motor symptoms by up to 6 years. Cardiovascular autonomic failure and early urinary catheterization were predictors of poorer outcomes. A normal supine plasma noradrenaline level in patients presenting with PAF phenotype is a possible autonomic biomarker indicating later conversion to MSA.

[Pathological Study of Pure Autonomic Failure].

Pure autonomic failure (PAF) is a subtype of Lewy body disease whose main target is the peripheral autonomic nervous system. The differential diagnosis includes multiple system atrophy and small fiber neuropathy like amyloidosis. Low uptake of 123I- metaiodebenzyl guanidine (MIBG) cardiac scintigraphy is of diagnosis use. Biopsy of skins affected with decreased sweating could prove Lewy pathology in the peripheral autonomic nerves. Among more than 10,000 autopsy cases in BBAR (Brain Bank for Aging Research), representing an aging cohort in Tokyo metropolitan suburban area, only two cases had clinical diagnosis of PAF. Orthostatic hypotension without parkinsonism is common clinical features. Both presented with diffuse Lewy body pathology involving the peripheral autonomic nervous system, brain stem, limbic system and neocortex with mild loss of pigmented neurons in substantia nigra. Other senile changes like Alzheimer pathology, argyrophlic grains and TDP43 (TAR DNA- binding protein of 43kDa) proteinopathy were mild. Neuropathological features fulfilled morphological criteria of dementia with Lewy bodies (DLB) pure neocortical form, suggesting dementia as one of the late clinical complications. About one third of autopsy cases registered to BBAR contained Lewy pathology in the body, among whom, 5% had Lewy pathology only in the peripheral autonomic nervous system. These cases may be the earliest stage of PAF.

The role of cardiovascular autonomic failure in the differential diagnosis of α-synucleinopathies.

The α-synucleinopathies comprise a group of adult-onset neurodegenerative disorders including Parkinson's disease (PD), multiple system atrophy (MSA), dementia with Lewy bodies (DLB,) and - as a restricted non-motor form - pure autonomic failure (PAF). Neuropathologically, the α-synucleinopathies are characterized by aggregates of misfolded α-synuclein in the central and peripheral nervous system. Cardiovascular autonomic failure is a common non-motor symptom in people with PD, a key diagnostic criterion in MSA, a supportive feature for the diagnosis of DLB and disease-defining in PAF. The site of autonomic nervous system lesion differs between the α-synucleinopathies, with a predominantly central lesion pattern in MSA versus a peripheral one in PD, DLB, and PAF. In clinical practice, overlapping autonomic features often challenge the differential diagnosis among the α-synucleinopathies, but also distinguish them from related disorders, such as the tauopathies or other neurodegenerative ataxias. In this review, we discuss the differential diagnostic yield of cardiovascular autonomic failure in individuals presenting with isolated autonomic failure, parkinsonism, cognitive impairment, or cerebellar ataxia.

Pure Autonomic Failure: A Case Report of Recurrent Orthostatic Hypotension.

Pure autonomic failure is a neurodegenerative disorder affecting the autonomic nervous system which clinically presents with orthostatic hypotension. It is a diagnosis of exclusion after detailed clinical examinations and relevant investigations. Here, we discuss a case of 68 years old male who had complaints of multiple episodes of loss of consciousness on standing from a sitting position for the last 3 years. The diagnosis was considered by clinical examinations revealing autonomic dysfunctions with normal appropriate investigations. The patient was treated successfully with midodrine, fludrocortisone, and other non-pharmacological interventions. We focused on doing various autonomic dysfunction tests in the evaluation of a patient with recurrent orthostatic hypotension. We suspect that pure autonomic failure might not have been considered in the differential diagnosis of recurrent orthostatic hypotension and suggest that it is to be kept as a differential in such a scenario. Midodrine has an effective role in syncope due to sympathetic vasoconstrictor failure.

Pure autonomic failure and the differential diagnosis of autonomic peripheral neuropathies.

PURPOSE OF REVIEW: Pure autonomic failure (PAF) is a peripheral autonomic neurodegenerative disease caused by alpha-synuclein deposition that is predominantly confined to peripheral autonomic neurons. Patients present with insidious features of autonomic failure that have a chronic course.In this review, we highlight the features of PAF, the differentiating features from other autonomic neuropathies, the diagnostic tests, and the predictors for conversion to a central synucleinopathy. RECENT FINDINGS: Natural history studies have defined the predictors for and rate of conversion to a central alpha-synucleinopathy. Skin immunohistochemistry techniques and demonstration of length-dependent neuronal loss of both somatic and autonomic small fiber nerves, and intraneural phosphorylated synuclein deposition provide diagnostic biomarkers. In the future, diagnosis maybe supported by measuring cerebrospinal fluid alpha-synuclein oligomers using techniques, such as protein misfolding cyclic amplification assay and real-time quaking-induced conversion. SUMMARY: PAF is a sporadic peripheral autonomic neurodegenerative disease that belongs to the group of disorders known as alpha-synucleinopathies. Peripheral autonomic manifestations are similar to those seen in other autonomic neuropathies, particularly, diabetic autonomic neuropathy, amyloid polyneuropathy, and autoimmune autonomic neuropathies. Novel diagnostic procedures like skin immunohistochemistry for alpha-synuclein, and protein amplification techniques are being investigated to provide an earlier and more specific diagnosis. A substantial number of PAF patients' phenoconvert to a central alpha-synucleinopathy.

Can novel non-invasive autonomic tests help discriminate between pure autonomic failure and multiple system atrophy?

BACKGROUND: Pure autonomic failure (PAF) and multiple system atrophy (MSA) are rare disorders causing severe autonomic failure. Their initially similar clinical presentation may lead to years of diagnostic difficulties. Improving the differentiation would have an important impact on patients and families in view of better prediction of disease progression. OBJECTIVE: To investigate whether several new non-invasive autonomic tests are beneficial in discriminating between PAF and MSA. METHODS: Patients and controls underwent two tests examining the autonomic innervation of the skin (Sudoscan and water-induced skin wrinkling) and one test measuring retinal nerve fiber layer thickness in the eye. RESULTS: The skin vasomotor tests yielded differences between the disease and control groups, but did not discriminate between PAF and MSA. No differences in retinal nerve fiber layer thickness were found between the groups. CONCLUSION: The tests applied in this study may help to confirm autonomic failure but did not support the differential diagnosis between PAF and MSA.

Predicting phenoconversion in pure autonomic failure.

OBJECTIVE: To determine predicting factors and frequency of phenoconversion from pure autonomic failure (PAF) into a synucleinopathy with motor or cognitive involvement of multiple system atrophy (MSA), Parkinson disease (PD), or dementia with Lewy bodies (DLB). METHODS: We performed a retrospective review of all patients with PAF from 2001 to 2011 evaluated at Mayo Clinic, Rochester. Clinical follow-up and patient telephone calls were used to assess for development of symptoms and diagnosis of MSA, PD, or DLB. Clinical and laboratory variables were extracted with factors predictive of evolution assessed using group comparison, odds ratio, and logistical regression. RESULTS: Among 275 patients with PAF at presentation, 67 (24%) phenoconverted to a synucleinopathy with motor or cognitive involvement; 34 met criteria for MSA, while 33 met criteria for PD or DLB. Age at onset was younger in MSA phenoconverters. Clinical features at presentation influenced phenoconversion: severe bladder symptoms were more common in MSA phenoconverters; subtle motor signs were more frequent in MSA and PD/DLB phenoconverters. MSA phenoconverters were more likely to have higher supine norepinephrine levels and preganglionic pattern of anhidrosis. Presentation variables predicting MSA phenoconversion included subtle motor signs, supine norepinephrine levels, severe bladder symptoms, and dream enactment behavior. Presentation variables predictive of PD/DLB phenoconversion included subtle motor signs, dream enactment behavior, and constipation. CONCLUSIONS: Our findings suggest that at least a quarter of patients with PAF phenoconvert to MSA, PD, or DLB. Presentation features determine patients at risk for evolution with specific patterns indicative of phenoconversion to MSA vs PD/DLB. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that several presentation variables including subtle motor signs, severe bladder symptoms, and dream enactment behavior are associated with an increased risk of developing a synucleinopathy with motor or cognitive involvement.

Pure Autonomic Failure.

Pure autonomic failure (PAF) is a neurodegenerative disorder of the autonomic nervous system clinically characterized by orthostatic hypotension. The disorder has also been known as Bradbury-Eggleston syndrome, named for the authors of the 1925 seminal description. Patients typically present in midlife or later with orthostatic hypotension or syncope. Autonomic failure may also manifest as genitourinary, bowel, and thermoregulatory dysfunction. With widespread involvement, patients may present to a variety of different specialties and require multidisciplinary treatment approaches. Pathologically, PAF is characterized by predominantly peripheral deposition of α-synuclein. However, patients with PAF may progress into other synucleinopathies with central nervous system involvement.

Pure autonomic failure presenting as Harlequin syndrome.

Pure autonomic failure (PAF) is a progressive syndrome of neurogenic orthostatic hypotension, widespread anhidrosis, urinary retention, and constipation without other neurologic manifestations. It is generally considered a peripheral ganglionic synucleinopathy. Natural history studies have described risk factors for the conversion of PAF to Parkinson's disease, multiple system atrophy, or dementia with Lewy bodies, yet the early stages of PAF are not well characterized. We present a patient with unilateral anhidrosis, contralateral facial flushing and hyperhidrosis consistent with Harlequin syndrome that, over 6 years, progressed to PAF, suggesting that PAF may present with focal autonomic impairment prior to generalized autonomic failure.

Usefulness of Blood Pressure Variability Indices Derived From 24-Hour Ambulatory Blood Pressure Monitoring in Detecting Autonomic Failure.

Background Increased blood pressure ( BP ) variability and nondipping status seen on 24-hour ambulatory BP monitoring are often observed in autonomic failure ( ATF ). Methods and Results We assessed BP variability and nocturnal BP dipping in 273 patients undergoing ambulatory BP monitoring at Southwestern Medical Center between 2010 and 2017. SD , average real variability, and variation independent of mean were calculated from ambulatory BP monitoring. Patients were divided into a discovery cohort (n=201) and a validation cohort (n=72). ATF was confirmed by formal autonomic function test. In the discovery cohort, 24-hour and nighttime average real variability, SD , and variation independent of mean did not differ significantly between ATF (n=25) and controls (n=176, all P>0.05). However, daytime SD, daytime coefficient of variation, and daytime variation independent of mean of systolic BP ( SBP ) were all significantly higher in patients with ATF than in controls in both discovery and validation cohorts. Nocturnal BP dipping was more blunted in ATF patients than controls in both cohorts (both P<0.01). Using the threshold of 16 mm Hg, daytime SD SBP yielded a sensitivity of 77% and specificity of 82% in detecting ATF in the validation cohort, whereas nondipping status had a sensitivity of 80% and specificity of 44%. The area under the receiver operator characteristic of daytime SD SBP was greater than the area under the receiver operator characteristic of nocturnal SBP dipping (0.79 [0.66-0.91] versus 0.73 [0.58-0.87], respectively). Conclusions Daytime SD of SBP is a better screening tool than nondipping status in detecting autonomic dysfunction.

Orthostatic Hypotension: JACC State-of-the-Art Review.

Neurogenic orthostatic hypotension is a highly prevalent and disabling feature of autonomic failure due to both peripheral and central neurodegenerative diseases. Community-based epidemiological studies have demonstrated a high morbidity and mortality associated with neurogenic orthostatic hypotension. It is due to impairment of baroreflex-mediated vasoconstriction of the skeletal muscle and splanchnic circulation and is caused by damage or dysfunction at central and/or peripheral sites in the baroreflex efferent pathway. Nonpharmacological and pharmacological interventions may be implemented to ameliorate the symptoms of orthostatic intolerance and improve quality of life. Many patients will be adequately treated by education, counseling, removal of hypotensive medications, and other nonpharmacological interventions, whereas more severely afflicted patients require pharmacological interventions. The first stage of pharmacological treatment involves repletion of central blood volume. If unsuccessful, this should be followed by treatment with sympathomimetic agents.

Orthostatic heart rate changes in patients with autonomic failure caused by neurodegenerative synucleinopathies.

OBJECTIVE: Blunted tachycardia during hypotension is a characteristic feature of patients with autonomic failure, but the range has not been defined. This study reports the range of orthostatic heart rate (HR) changes in patients with autonomic failure caused by neurodegenerative synucleinopathies. METHODS: Patients evaluated at sites of the U.S. Autonomic Consortium (NCT01799915) underwent standardized autonomic function tests and full neurological evaluation. RESULTS: We identified 402 patients with orthostatic hypotension (OH) who had normal sinus rhythm. Of these, 378 had impaired sympathetic activation (ie, neurogenic OH) and based on their neurological examination were diagnosed with Parkinson disease, dementia with Lewy bodies, pure autonomic failure, or multiple system atrophy. The remaining 24 patients had preserved sympathetic activation and their OH was classified as nonneurogenic, due to volume depletion, anemia, or polypharmacy. Patients with neurogenic OH had twice the fall in systolic blood pressure (SBP; -44 ± 25 vs -21 ± 14 mmHg [mean ± standard deviation], p < 0.0001) but only one-third of the increase in HR of those with nonneurogenic OH (8 ± 8 vs 25 ± 11 beats per minute [bpm], p < 0.0001). A ΔHR/ΔSBP ratio of 0.492 bpm/mmHg had excellent sensitivity (91.3%) and specificity (88.4%) to distinguish between patients with neurogenic from nonneurogenic OH (area under the curve = 0.96, p < 0.0001). Within patients with neurogenic OH, HR increased more in those with multiple system atrophy (p = 0.0003), but there was considerable overlap with patients with Lewy body disorders. INTERPRETATION: A blunted HR increase during hypotension suggests a neurogenic cause. A ΔHR/ΔSBP ratio < 0.5 bpm/mmHg is diagnostic of neurogenic OH. Ann Neurol 2018;83:522-531.

Diagnosis of multiple system atrophy.

Multiple system atrophy (MSA) may be difficult to distinguish clinically from other disorders, particularly in the early stages of the disease. An autonomic-only presentation can be indistinguishable from pure autonomic failure. Patients presenting with parkinsonism may be misdiagnosed as having Parkinson disease. Patients presenting with the cerebellar phenotype of MSA can mimic other adult-onset ataxias due to alcohol, chemotherapeutic agents, lead, lithium, and toluene, or vitamin E deficiency, as well as paraneoplastic, autoimmune, or genetic ataxias. A careful medical history and meticulous neurological examination remain the cornerstone for the accurate diagnosis of MSA. Ancillary investigations are helpful to support the diagnosis, rule out potential mimics, and define therapeutic strategies. This review summarizes diagnostic investigations useful in the differential diagnosis of patients with suspected MSA. Currently used techniques include structural and functional brain imaging, cardiac sympathetic imaging, cardiovascular autonomic testing, olfactory testing, sleep study, urological evaluation, and dysphagia and cognitive assessments. Despite advances in the diagnostic tools for MSA in recent years and the availability of consensus criteria for clinical diagnosis, the diagnostic accuracy of MSA remains sub-optimal. As other diagnostic tools emerge, including skin biopsy, retinal biomarkers, blood and cerebrospinal fluid biomarkers, and advanced genetic testing, a more accurate and earlier recognition of MSA should be possible, even in the prodromal stages. This has important implications as misdiagnosis can result in inappropriate treatment, patient and family distress, and erroneous eligibility for clinical trials of disease-modifying drugs.

Symptomatic therapy of multiple system atrophy.

Multiple system atrophy is a progressive neurodegenerative disease characterized by the association of autonomic failure and a movement disorder that consist of either a hypokinetic movement disorder or a cerebellar syndrome or both. In addition to these core characteristics other movement disorders (e.g. dystonia, myoclonus, spasticity), and neuropsychiatric symptoms (e.g. depression, cognitive dysfunction) may occur in the course of the disease and can severely impair patients' quality of live. To date no causal therapy is available and therefore symptomatic treatment plays a pivotal role in patient care. In this article we provide an overview of frequent clinical symptoms and their symptomatic treatment options.