CSF neurofilament light chain profiling and quantitation in neurological diseases.

Neurofilament light chain is an established marker of neuroaxonal injury that is elevated in CSF and blood across various neurological diseases. It is increasingly used in clinical practice to aid diagnosis and monitor progression and as an outcome measure to assess safety and efficacy of disease-modifying therapies across the clinical translational neuroscience field. Quantitative methods for neurofilament light chain in human biofluids have relied on immunoassays, which have limited capacity to describe the structure of the protein in CSF and how this might vary in different neurodegenerative diseases. In this study, we characterized and quantified neurofilament light chain species in CSF across neurodegenerative and neuroinflammatory diseases and healthy controls using targeted mass spectrometry. We show that the quantitative immunoprecipitation-tandem mass spectrometry method developed in this study strongly correlates to single-molecule array measurements in CSF across the broad spectrum of neurodegenerative diseases and was replicable across mass spectrometry methods and centres. In summary, we have created an accurate and cost-effective assay for measuring a key biomarker in translational neuroscience research and clinical practice, which can be easily multiplexed and translated into clinical laboratories for the screening and monitoring of neurodegenerative disease or acute brain injury.

A Systematic Review of the Spectrum and Prevalence of Non-Motor Symptoms in Adults with Hereditary Cerebellar Ataxias.

Background: Cerebellar ataxias comprise a large group of heterogeneous disorders with both motor and non-motor symptoms (NMS). Objective: We wanted to ascertain the reported prevalence of NMS in different subtypes of hereditary cerebellar ataxias. Methods: Systematic review of studies of hereditary cerebellar ataxias (involving >5 patients) who were assessed for NMS, published in the English literature in PUBMED and EMBASE databases from 1947 to 2021. Results: A total of 35 papers, with data from 1311 autosomal dominant spinocerebellar ataxia (SCA), 893 autosomal recessive cerebellar ataxia (ARCA), and 53 X-linked ataxia cases were included with a total of 450 controls. Mean age for SCA cases at diagnosis was 47.6 (SD, 14.9) years, for ARCA cases was 34.6 (SD, 14.7) years and for X-linked ataxia cases was 68.6 (9.1) years. The prevalence of cognitive problems in SCAs was between 23% and 75% (ranging from mild to severe), being least prevalent in SCA6. The prevalence of depression in SCAs was between 13% and 69% and sleep disorders were between 7% and 80%. Pain was reported by 18% to 60% of patients, especially in SCA3, and fatigue by 53% to 70%. The prevalence of reported cognitive dysfunction in ARCA was 12.5% to 100% and depression between 14% and 51%. The prevalence of anxiety in X-linked ataxias (FXTAS) was 17 % and depression 55%. Conclusions: The presence of NMS in hereditary cerebellar ataxias is common. The prevalence and spectrum of NMS in SCAs, ARCAs, and X-linked ataxias vary. In routine clinical practice, NMS in cerebellar ataxias are under-recognized and certainly under-reported. Therefore, they are unlikely to be addressed adequately. Improved ascertainment of NMS in cerebellar ataxias in clinical practice will enable holistic treatment of these patients.

Hepatitis C during disease modifying therapy with Fingolimod for Relapsing Remitting Multiple Sclerosis: diagnosis and treatment.

We present a case of 48-year-old woman with relapsing remitting multiple sclerosis (MS), who switched disease modifying therapy from Copaxone to Fingolimod due to her clinical and radiological MS disease progression. Unexpectedly after 2.5 years of stable MS symptoms and liver function tests (LFTs), we noted deranged LFTs during routine testing. Additional investigations showed hepatitis C positivity, genotype 3. It is likely a case of hepatitis C reactivation secondary to prolonged immunosuppressive effects of Fingolimod. Although the increased risk of viral reactivation related to varicella zoster virus is known to occur with Fingolimod treatment, to our knowledge, this is only the second case of hepatitis C disease activity reported with Fingolimod treatment. We would like to raise the awareness of hepatitis C viral reactivation as a possible complication of prolonged immunosuppression with Fingolimod.