Neurosarcoidosis: Clinical, biological, and MRI presentation of central nervous system disease in a national multicenter cohort.

INTRODUCTION: Neurosarcoidosis (NS) is a systemic inflammatory granulomatous disease affecting of patients with sarcoidosis. Its diagnosis is difficult as there is no specific test for it. Because of its rarity, the management of NS has so far only been described in case series and short retrospective cohorts. The objective of this study is description of the clinical, paraclinical presentation and the therapeutic management of central nervous system (CNS) involvement in NS patients in France. METHODS: This multicenter, retrospective, observational study involved patients hospitalized between 2010 and 2019 with a diagnosis of sarcoidosis and CNS involvement. RESULTS: We included 118 patients (38 with isolated NS, 80 with NS associated with systemic sarcoidosis). NS was the initial presentation in 78% of patients, with cranial nerve involvement (36%), medullary symptoms (23%), and seizures (21%). Twenty-one percent of the patients had already been diagnosed with systemic sarcoidosis. The most frequent biological abnormality was lymphopenia (62.5%), while angiotensin-converting enzyme was increased in 21%. Meningitis was present in 45% and hyperproteinorachia in 69.5% of cases. MRI mainly revealed white matter abnormalities and leptomeningeal enhancement (34%). Corticosteroids were the most useful treatment, and immunosuppressive agents were used in steroid-resistant patients and to limit side effects. Methotrexate, cyclophosphamide, and anti-TNFα were also used, exhibiting good efficacy. CONCLUSIONS: This cohort contributes to a better understanding of the clinical phenotype and associated imaging and biological abnormalities. Sharing of clinical, biological, and imaging data, as well as the therapeutic responses, of patients with NS helps to better understand and manage this disease that affects a small number of patients per center. A database project could be implemented in the future to enable this.

Defining the course of neurosarcoidosis according to presentation at onset and disease modifying treatment: a cohort study of 84 patients.

Background: Neurosarcoidosis is a rare manifestation of sarcoidosis with heterogeneous presentations. Patient management is challenging due to the current lack of knowledge about the long-term disease course. Objective: To identify specific disease courses of neurosarcoidosis according to the clinical and paraclinical presentations at onset. Methods: We conducted an observational multicenter cohort study by retrospectively collecting data from the medical records of 84 patients diagnosed with definite, probable, or possible neurosarcoidosis in three tertiary referral centers in France (Nancy, Strasbourg, and Bordeaux). We collected demographic characteristics, clinical and paraclinical data at the beginning of patient management, and during follow-up under the different treatment lines. Two expert neurologists determined disease course profiles. Results: The mean follow-up was 6.6 years. Almost every patient (96.4%) received steroids at some point of their follow-up. Tumor Necrosis Factor-alpha blockers were given in 10.7% as first-line treatment and in 33.3% during follow-up. Every patient presented with a relapsing disease, often monophasic (75%) and sometimes polyphasic with the recurrence of identical manifestations (11.9%). Patients developing new neurological symptoms during follow-up were a minority (13.1%). No patients exhibited a progressive course. Patients with isolated cranial nerves injury or aseptic meningitis always exhibited a monophasic course, and 62.5-75% of them had a full recovery after first-line treatments. This proportion was 15.6% in other forms of the disease. Those with peripheral presentations were more likely to present a polyphasic course than patients with other forms of neurosarcoidosis. Spinal cord presentations were monophasic, but resulted in sequelae and exhibited poor response to first-line treatments despite frequent use of TNF-alpha blockers. Conclusion: Identification of these disease course profiles, based on the initial clinical and paraclinical presentation, could guide the clinician to select the optimal therapeutic approach and follow-up modalities for their patients with neurosarcoidosis.

Optimized testing strategy for the diagnosis of GAA-FGF14 ataxia/spinocerebellar ataxia 27B.

Dominantly inherited GAA repeat expansions in FGF14 are a common cause of spinocerebellar ataxia (GAA-FGF14 ataxia; spinocerebellar ataxia 27B). Molecular confirmation of FGF14 GAA repeat expansions has thus far mostly relied on long-read sequencing, a technology that is not yet widely available in clinical laboratories. We developed and validated a strategy to detect FGF14 GAA repeat expansions using long-range PCR, bidirectional repeat-primed PCRs, and Sanger sequencing. We compared this strategy to targeted nanopore sequencing in a cohort of 22 French Canadian patients and next validated it in a cohort of 53 French index patients with unsolved ataxia. Method comparison showed that capillary electrophoresis of long-range PCR amplification products significantly underestimated expansion sizes compared to nanopore sequencing (slope, 0.87 [95% CI, 0.81 to 0.93]; intercept, 14.58 [95% CI, - 2.48 to 31.12]) and gel electrophoresis (slope, 0.84 [95% CI, 0.78 to 0.97]; intercept, 21.34 [95% CI, - 27.66 to 40.22]). The latter techniques yielded similar size estimates. Following calibration with internal controls, expansion size estimates were similar between capillary electrophoresis and nanopore sequencing (slope: 0.98 [95% CI, 0.92 to 1.04]; intercept: 10.62 [95% CI, - 7.49 to 27.71]), and gel electrophoresis (slope: 0.94 [95% CI, 0.88 to 1.09]; intercept: 18.81 [95% CI, - 41.93 to 39.15]). Diagnosis was accurately confirmed for all 22 French Canadian patients using this strategy. We also identified 9 French patients (9/53; 17%) and 2 of their relatives who carried an FGF14 (GAA)≥250 expansion. This novel strategy reliably detected and sized FGF14 GAA expansions, and compared favorably to long-read sequencing.