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Background Despite being long neglected, olfaction has recently become a focus of intense research in neuroscience, as smell impairment has been consistently documented in both neurodegenerative and neuroinflammatory diseases. Considering the close anatomo-functional correlations between the limbic system and the central olfactory structures, we investigated olfaction in a population of patients with autoimmune encephalitis (AE). Methods Nineteen adult subjects (14 males, median age 64 years) diagnosed with definite (14/19) or possible (5/19) AE and followed for ≥ 6 months were enrolled. The Brief Smell Identification Test (B-SIT), a 12-item, forced-choice, scratch-and-sniff measure, was used to assess the patients’ olfactory function in comparison with a group of sex- and age-matched healthy controls (HC). According to the B-SIT score, subjects were classified as anosmic (

Autoimmune encephalitis associated with antibodies against neuronal surface targets (NSAE) are rare but still underrecognized conditions that affect adult and pediatric patients. Clinical guidelines have recently been published with the aim of providing diagnostic clues regardless of antibody status. These syndromes are potentially treatable but the choice of treatment and its timing, as well as differential diagnoses, long-term management, and clinical and paraclinical follow-up, remain major challenges. In the absence of evidence-based guidelines, management of these conditions is commonly based on single-center expertise. Taking into account different published expert recommendations in addition to the multicenter experience of the Italian Working Group on Autoimmune Encephalitis, both widely accepted and critical aspects of diagnosis, management and particularly of immunotherapy for NSAE have been reviewed and are discussed. Finally, we provide consensus-based practical advice for managing hospitalization and follow-up of patients with NSAE.

Epidemiologic data on neuronal surface antibody (NSAb)-associated autoimmune encephalitides (NSAE) are scarce and heterogeneous. We review our 13-year-long biobank-data collection and provide the incidence of NSAE in two Italian provinces (approx. Population of 1,400,000) over a 5-year period (July 2013-June 2018). NSAbs were diagnosed in 75 out of 1179 tested patients (6.4%). The most common NSAbs were anti-LGI1 (30 cases), followed by NMDAR (24). Eleven cases of NSAE were diagnosed in Treviso and Trento provinces with an estimated incidence of 1.54 per 1,000,000 population (LGI1-encephalitis 0.84; C.I. 0.38-1.88). LGI1-E is the most frequent NSAE among adults.

Background: It is unclear how multiple sclerosis (MS) affects the severity of Covid-19. Methods: Hospitalization, Intensive Care Unit (ICU) admission and death after Covid-19 diagnosis of 1362 MS patients were compared to the age and sex-matched Italian population in a retrospective observational case-cohort study with population-based control. The observed vs the expected events were compared in the whole MS cohort and in different subgroups (higher-risk: EDSS>3 or at least one comorbidity, lower-risk: EDSS

Background and purpose : Autoimmune encephalitides (AE) include a spectrum of neurological disorders whose diagnosis revolves around the detection of neuronal antibodies (Abs). Consensus-based diagnostic criteria (AE-DC) allow clinic-serological subgrouping of AE, with unclear prognostic implications. The impact of AE-DC on patients’ management was studied, focusing on the subgroupofAb-negative-AE. Methods: This was a retrospective multicenter study on patients fulfilling AE-DC. All patients underwent Ab testing with commercial cell-based assays (CBAs) and, when available, in-house assays (immunohistochemistry, live/fixed CBAs, neuronal cultures) that contributed to defining final categories. Patients were classified as Ab-positive-AE [N-methyl-d-aspartate-receptor encephalitis (NMDAR-E), Ab-positive limbic encephalitis (LE), definite-AE] or Ab-negative-AE (Ab-negative-LE, probable-AE, possible-AE). Results: Commercial CBAs detected neuronal Abs in 70/118 (59.3%) patients. Testing 37/48 Ab-negative cases, in-house assays identified Abs in 11 patients (29.7%). A hundred and eighteen patients fulfilled the AE-DC, 81 (68.6%) with Ab-positive-AE (Ab-positive-LE, 40; NMDAR-E, 32; definite-AE, nine) and 37 (31.4%) with Ab-negative-AE (Ab-negative-LE, 17; probable/possible-AE, 20). Clinical phenotypes were similar in Ab-positive-LE versus Ab-negative-LE. Twenty-four/118 (20.3%) patients had tumors, and 19/118 (16.1%) relapsed, regardless of being Ab-positive or Ab-negative. Ab-positive-AE patients were treated earlier than Ab-negative-AE patients (P=0.045), responded more frequently to treatments (92.3% vs. 65.6%, P&nbsp

Anti-myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) recently emerged as a potential biomarker in patients with inflammatory demyelinating diseases of the central nervous system. We here compare the clinical and laboratory findings observed in a cohort of MOG-Ab seropositive and seronegative cases and describe IgG subclass analysis results. Consecutive serum samples referred to Verona University Neuropathology Laboratory for aquaporin-4 (AQP4)-Ab and/or MOG-Ab testing were analysed between March 2014 and May 2017. The presence of AQP4-Ab was determined using a cell-based assay. A live cell immunofluorescence assay was used for the detection of MOG-IgG and IgG subclass analysis. Among 454 analysed samples, 29 were excluded due to AQP4-Ab positivity or to the final demonstration of a disorder not compatible with MOG-Ab. We obtained clinical data in 154 out of 425 cases. Of these, 22 subjects resulted MOG-Ab positive. MOG-Ab positive patients were mainly characterised by the involvement of the optic nerve and/or spinal cord. Half of the cases presented relapses and the recovery was usually partial. Brain MRI was heterogeneous while short lesions were the prevalent observation on spinal cord MRI. MOG-Ab titre usually decreased in non-relapsing cases. In all MOG-IgG positive cases, we observed IgG1 antibodies, which were predominant in most subjects. IgG2 (5/22), IgG3 (9/22) and IgG4 (3/22) antibodies were also detectable. We confirm that MOG-Ab-related syndromes have distinct features in the spectrum of demyelinating conditions, and we describe the possible role of the different IgG subclasses in this condition. Electronic supplementary material The online version of this article (doi:10.1007/s00415-017-8635-4) contains supplementary material, which is available to authorized users.

Leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) neurological autoimmunity in adults has been associated with various clinical syndromes involving central, peripheral and autonomic nervous system, while data in children is limited. We perform the first systematic literature review on paediatric LGI1 and CASPR2 autoimmunity, with focus on clinical data, in order to contribute to the definition of clinical features of LGI1 and CASPR2 autoimmunity in paediatric age and favour early diagnosis. Additionally, we report the youngest-to-date case of Morvan syndrome. We identified 37 published paediatric cases of LGI1 and/or CASPR2 autoimmunity. Most frequent syndromes were encephalitis in LGI1-positive and isolated epilepsy in CASPR2-positive children, while syndromes with predominant peripheral symptoms were most frequent in double-positive children. With the limitations imposed by the low number of cases, differences to published adult cohorts included: absence of faciobrachial dystonic seizures and hyponatremia in patients with LGI1-positive encephalitis; slightly higher proportion of isolated epilepsy syndromes in CASPR2-positive patients; absence of tumour in the whole cohort.

Circulating and cerebrospinal fluid (CSF) neurofilament light chain (NfL) levels represent a reliable indicator of disease activity and axonal damage in different neuroinflammatory conditions. Recently, high CSF NfL levels have been detected in active autoimmune encephalitis, as opposed to significant lower levels after clinical improvement. The aim of the present study was to evaluate serum and CSF NfL concentration in patients with autoimmune encephalitis and to analyse the association between NfL levels and clinical, MRI, and CSF data. We retrospectively included 25 patients with neurological syndromes associated with autoantibodies to neuronal cell surface antigens and we collected clinical, MRI, CSF, and follow-up data. Using an ultrasensitive method (Simoa, Quanterix), we measured NfL levels in serum and CSF samples of all patients and in 25 sera of healthy controls. Serum NfL levels were higher in all cases, including 20 patients with inflammatory MRI/CSF features and 5 non-inflammatory cases (median 16.9 pg/ml, range 4.5–90) than in controls (median 6.9 pg/ml, range 2.7–12.8; p

Objective To evaluate disease activity according to rituximab (RTX) induction and maintenance regimens in a multicenter real-life dataset of NMOSD patients. Methods This is an observational-retrospective multicentre study including patients with NMOSD treated with RTX in 21 Italian and 1 Swiss centers. Demographics, relapse rate and adverse events over the follow-up were summarized taking into account induction strategy (two-1 g infusions at a 15-day interval (IND-A) vs. 375 mg/m2/week infusions for one month (IND-B)) and maintenance therapy (regimen A (M-A) with fixed time-points infusions vs. regimen B (M-B) based on cytofluorimetric driven reinfusion regimens, the least further subdivided according to CD19+ B cells (M-B1) or CD27+ memory B cells (M-B2) monitoring). Results 131 subjects were enrolled, 127 patients completed the induction regimen and 119 patients had at least one follow-up visit and were included in the outcome analysis. Median follow-up was 1.7 years (range 0.1–11.6). Annualized relapse rate (ARR) was 1.7 in the year before RTX start and decreased to 0.19 during the follow-up. Both ARR and Time to first relapse (TTFR) analysis showed a trend toward an increased disease activity for IND-B and M-A. No patients with MT-B2 experienced relapses during the follow-up. Number of relapses in the year before RTX initiation and having received a previous treatment were significantly associated with higher ARR and reduced TTFR in the multivariate analysis. Interpretation We confirm RTX efficacy in NMOSD patients. Use of specific induction and maintenance protocols is warranted in order to foster RTX efficacy and to reduce costs and side effects.

Purpose: Radiological hallmark of autoimmune limbic encephalitis (LE) is a hyperintense signal in MRI T2-weighted images of mesial temporal structures. We aimed to identify conventional magnetic resonance imaging (MRI) features that can help distinguish LE from temporal glioma. Methods: Brain MRIs of 25 patients affected by antibody-positive autoimmune LE, 24 patients affected by temporal glioma (tumor group), and 5 negative controls were retrospectively blindly evaluated in random order. Results: Ten brain MRIs from the LE group were correctly recognized; one additional patient with mesial temporal hyperintensity with anti-AK5 abs LE was wrongly diagnosed as having a tumor. The brain MRIs of the remaining 14 of the 25 patients with LE were judged negative or, in three cases, showed features not typical for LE. In the tumor group, all MRIs showed pathological alterations diagnosed as tumors in 22/24 cases and as LE in two (2/22, 9%). Unilateral lesions were more common in tumors than in neuroradiologically abnormal LE (96% vs. 18%, p < 0.001). T2/FLAIR hyperintensity of the parahippocampal gyrus was associated more with tumor than with LE (71% vs. 18%) (p = 0,009), as T2/FLAIR hyperintensity of extralimbic structures (p = 0.015), edema (p = 0.041), and mass effect (p = 0.015). Maintenance of gray/white matter distinction was strongly associated with LE (91% vs. 17%, p < 0.001). Conclusion: Conventional brain MRI is a fundamental tool in the differential diagnosis between LE and glioma. Bilateral involvement and maintenance of gray/white matter distinction at the cortical/subcortical interface are highly suggestive of LE.

To contribute to characterize electroencephalographic (EEG) activity in pediatric anti- N-methyl-d-aspartate (anti-NMDA) receptor encephalitis, we reviewed electroclinical data of 5 children with anti-NMDA receptor encephalitis diagnosed in our department. We identified 4 longitudinal electroencephalographic phases: in the early phase, background activity was normal, with intermixed nonreactive slow waves; in the florid phase, background activity deteriorated with appearance of sequences of peculiar rhythmic theta and/or delta activity unrelated to clinical changes, unresponsive to stimuli and antiepileptic medications; in the recovery phase, these sequences decreased and reactive posterior rhythm re-emerged; electroencephalogram normalized 2 to 5 months after onset. In conclusion, in the presence of evocative clinical history, recognizing a characteristic longitudinal electroencephalographic activity could provide ancillary aspects addressing the diagnosis and the overall management of children with anti- N-methyl-d-aspartate receptor encephalitis; in particular, knowing that peculiar and recurrent paroxysmal nonepileptic rhythmic theta-delta patterns can occur in these patients could help distinguish paroxysmal epileptic and nonepileptic electroencephalographic activity.

Objective: A study was undertaken to describe the clinical spectrum, voltage-gated potassium channel (VGKC) complex antibody specificities, and central nervous system localization of antibody binding in 29 patients diagnosed with Morvan syndrome (MoS). Methods: Clinical data were collected using questionnaires. Radioimmunoassay, cell-based assays, and mouse brain immunohistochemistry were used to characterize the serum antibodies. Results: Neuromyotonia (100%), neuropsychiatric features (insomnia 89.7%, confusion 65.5%, amnesia 55.6%, hallucinations 51.9%), dysautonomia (hyperhidrosis 86.2%, cardiovascular 48.3%), and neuropathic pain (62.1%) were the most common manifestations. A total of 93.1% of MoS patients were male. VGKC-complex antibodies were present in 23 of 29 (79%) MoS patients at referral; 24 of 27 available sera had CASPR2, LGI1, or both CASPR2 and LGI1 antibodies (3 also with contactin-2 antibodies). CASPR2 antibodies were generally higher titer than LGI1 antibodies. Tumors (41.4%), mainly thymomas, were associated with CASPR2 antibodies and a poor prognosis, whereas LGI1 antibodies were associated with serum hyponatremia. In brain tissue regions including the hypothalamus, raphe, and locus coeruleus, commercial antibodies to LGI1 bound to neuronal cell bodies including the antidiuretic hormone-secreting and orexin-secreting hypothalamic neurons, whereas CASPR2 commercial antibodies bound more often to the neuropil. MoS antibodies bound similarly, but there was evidence of additional antibodies in some sera that were not adsorbed by LGI1- or CASPR2-expressing cells and bound to mouse Caspr2−/− tissue. Interpretation: MoS is clinically distinct from other VGKC-complex antibody-associated conditions, and usually is associated with high-titer CASPR2 antibodies, often accompanied by lower-titer LGI1 antibodies. CASPR2 and LGI1 antibodies bind to multiple brain regions, which helps to explain the multifocal clinical features of this disease, but other antibodies are likely to play a role in some patients and need to be characterized in future studies. ANN NEUROL 2012

Antibodies to the N-methyl-d-aspartate subtype of glutamate receptor have been associated with a newly-described encephalopathy that has been mainly identified in young females with ovarian tumours. However, the full clinical spectrum and treatment responses are not yet clear. We established a sensitive cell-based assay for detection of N-methyl-d-aspartate receptor antibodies in serum or cerebrospinal fluid, and a quantitative fluorescent immunoprecipitation assay for serial studies. Although there was marked intrathecal synthesis of N-methyl-d-aspartate receptor antibodies, the absolute levels of N-methyl-d-aspartate receptor antibodies were higher in serum than in cerebrospinal fluid. N-methyl-d-aspartate receptor antibodies were of the immunoglobulin G1 subclass and were able to activate complement on N-methyl d-aspartate receptor-expressing human embryonic kidney cells. From questionnaires returned on 44 N-methyl-d-aspartate receptor antibody-positive patients, we identified a high proportion without a detected tumour (35/44, 80: follow-up 3.6-121 months, median 16 months). Among the latter were 15 adult females (43), 10 adult males (29) and 10 children (29), with four in the first decade of life. Overall, there was a high proportion (29) of non-Caucasians. Good clinical outcomes, as defined by reductions in modified Rankin scores, correlated with decreased N-methyl-d-aspartate receptor antibody levels and were associated with early (

Background: The spectrum of autoimmune neurological diseases associated with voltage-gated potassium channel (VGKC)-complex antibodies (Abs) ranges from peripheral nerve disorders to limbic encephalitis. Recently, low titers of VGKC-complex Abs have also been reported in neurodegenerative disorders, but their clinical relevance is unknown. Objective: The aim of the study was to explore the prevalence of VGKC-complex Abs in slow-progression motor neuron disease (MND). Methods: We compared 11 patients affected by slow-progression MND with 9 patients presenting typical progression illness. Sera were tested for VGKC-complex Abs by radioimmunoassay. The distribution of VGKC-complex Abs was analyzed with the Mann-Whitney U test. Results: The statistical analysis showed a significant difference between the mean values in the study and control groups. A case with long-survival MND harboring VGKC-complex Abs and treated with intravenous immunoglobulins is described. Conclusion: Although VGKC-complex Abs are not likely to be pathogenic, these results could reflect the coexistence of an immunological activation in patients with slow disease progression.

Background Patients with the syndrome of headache with neurological deficits and lymphocytosis (HaNDL) typically present with recurrent and temporary attacks of neurological symptoms and cerebrospinal fluid lymphocytosis. Aim and methods To identify potential HaNDL‐associated antibodies directed against neuronal surface and/or synapse antigens, sera of four HaNDL patients and controls were screened with indirect immunohistochemistry, immunofluorescence, cell-based assay, radioimmunoassay, protein macroarray and enzyme-linked immunosorbent assay (ELISA). Results Although HaNDL sera did not yield antibodies to any of the well-characterized neuronal surface or synapse antigens, protein macroarray and ELISA studies showed high-titer antibodies to a subunit of the T-type voltage-gated calcium channel (VGCC), CACNA1H, in sera of two HaNDL patients. Conclusion Our results support the notion that ion channel autoimmunity might at least partially contribute to HaNDL pathogenesis and occurrence of neurological symptoms.

Few population studies are available on epidemiological indexes of hereditary ataxias. An investigation on the prevalence rate of these movement disorders is in progress for the Veneto region, the main area of northeast Italy with a population of 4,490,586 inhabitants. The first results of this epidemiological survey concern the province of Padua, which numbers 845,203 residents (January 1, 2002). The prevalence rate of inherited ataxias has been estimated at 93.3 cases per million inhabitants. The most common types appeared to be the autosomal dominant forms, namely spinocerebellar ataxia type 1 and 2, with a prevalence of 24 per 1,000,000. In the same population, with a prevalence rate of 6 per 1,000,000, Friedreich’s ataxia was defined as the prominent recessive autosomal form. There were very rare cases of ataxia telangiectasia, ataxia with vitamin E deficiency and cerebellar ataxia with congenital muscular dystrophy, a recently identified autosomal recessive disease.

No disease-specific neuronal antibodies have so far been defined in neuro-Behcet's disease (NBD). Immunohistochemistry and immunocytochemistry studies showed antibodies to hippocampal and cerebellar molecular layers and the surface antigens of cultured hippocampal neurons in sera and/or cerebrospinal fluids (CSF) of 13 of 20 NBD and 6 of 20 BD patients but not in multiple sclerosis or headache controls. Screening with a protein macroarray led to identification of stress-induced-phosphoprotein-1 (STIP-1) as an antigenic target. High-titer STIP-1-antibodies were detected in 6 NBD patients' sera but not in controls. These results suggest that neuronal antibodies could be useful as diagnostic biomarkers in NBD. (C) 2011 Elsevier B.V. All rights reserved.

Paraneoplastic limbic encephalitis (PLE) associated with small cell lung cancer (SCLC) often presents with antibodies to intracellular antigens and a poor outcome even after tumor resection and immunotherapy. We report a PLE patient presenting with generalized seizures, shortterm memory impairment and medial temporal lobe hyperintensity in MRI. Initial screening revealed significantly elevated thyroid antibody levels suggesting Hashimoto's encephalopathy. Following methylprednisolone treatment, her seizures ceased, MRI findings disappeared and memory impairment showed a partial resolution in 5 months. Two months later, she developed further generalized seizures. Chest X-ray showed a mass lesion, which was demonstrated by needle biopsy to be a small cell lung carcinoma (SCLC). The panel of onconeural antibodies including cell-membrane antigens was negative. However, the patient's serum and cerebrospinal fluid IgG, obtained during both exacerbations, immunolabeled cytoplasm and dendrites of Purkinje cells, cerebellar and hippocampal molecular layers, basal ganglia, thalamus, and the surface of cultured hippocampal neurons, in a manner distinct from previously identified neuropil antibodies associated with SCLC. These neuropil antibodies appear to be associated with a favorable response to treatment. Further studies are required for determination of the target antigen.

Antibodies that immunoprecipitate (125)I-alpha-dendrotoxin-labelled voltage-gated potassium channels extracted from mammalian brain tissue have been identified in patients with neuromyotonia, Morvan's syndrome, limbic encephalitis and a few cases of adult-onset epilepsy. These conditions often improve following immunomodulatory therapies. However, the proportions of the different syndromes, the numbers with associated tumours and the relationships with potassium channel subunit antibody specificities have been unclear. We documented the clinical phenotype and tumour associations in 96 potassium channel antibody positive patients (titres >400 pM). Five had thymomas and one had an endometrial adenocarcinoma. To define the antibody specificities, we looked for binding of serum antibodies and their effects on potassium channel currents using human embryonic kidney cells expressing the potassium channel subunits. Surprisingly, only three of the patients had antibodies directed against the potassium channel subunits. By contrast, we found antibodies to three proteins that are complexed with (125)I-alpha-dendrotoxin-labelled potassium channels in brain extracts: (i) contactin-associated protein-2 that is localized at the juxtaparanodes in myelinated axons; (ii) leucine-rich, glioma inactivated 1 protein that is most strongly expressed in the hippocampus; and (iii) Tag-1/contactin-2 that associates with contactin-associated protein-2. Antibodies to Kv1 subunits were found in three sera, to contactin-associated protein-2 in 19 sera, to leucine-rich, glioma inactivated 1 protein in 55 sera and to contactin-2 in five sera, four of which were also positive for the other antibodies. The remaining 18 sera were negative for potassium channel subunits and associated proteins by the methods employed. Of the 19 patients with contactin-associated protein-antibody-2, 10 had neuromyotonia or Morvan's syndrome, compared with only 3 of the 55 leucine-rich, glioma inactivated 1 protein-antibody positive patients (P < 0.0001), who predominantly had limbic encephalitis. The responses to immunomodulatory therapies, defined by changes in modified Rankin scores, were good except in the patients with tumours, who all had contactin-associated-2 protein antibodies. This study confirms that the majority of patients with high potassium channel antibodies have limbic encephalitis without tumours. The identification of leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 as the major targets of potassium channel antibodies, and their associations with different clinical features, begins to explain the diversity of these syndromes; furthermore, detection of contactin-associated protein-2 antibodies should help identify the risk of an underlying tumour and a poor prognosis in future patients.

Limbic encephalitis is characterised by subacute development of short-term memory loss, seizures, confusion and psychiatric features.1 Paraneoplastic limbic encephalitis is generally associated with small cell lung cancer (SCLC), and around 50% of patients harbour Hu, CV2/CRMP5 or amphiphysin antibodies.1 Recently, antibodies against voltage-gated potassium channels (VGKC-abs) were identified as a new marker of a non-paraneoplastic, immunotherapy-responsive form of limbic encephalitis.2,3 However, the presence of VGKC-ab does not exclude a paraneoplastic cause of limbic encephalitis.1 We described previously a new antibody called anti-glial nuclear antibody (AGNA), a marker of SCLC shown to be closely associated with paraneoplastic Lambert–Eaton myasthenic syndrome (LEMS).4 Here we report on two patients with paraneoplastic limbic encephalitis associated with SCLC and VGKC-ab who also presented AGNA. The presence of AGNA was assessed by immunohistochemistry on frozen sections of paraformaldehyde-fixed rat cerebellum in nine patients with limbic encephalitis and SCLC with (n = 2) or without (n = 7) VGKC-ab, and in seven patients with non-paraneoplastic limbic encephalitis and VGKC-ab. To confirm AGNA reactivity, an immunohistochemical competition assay was performed as described previously.4 VGKC-abs were detected by radioimmunoprecipitation (cutoff value: 100 pmol/l).2 A middle-aged man was admitted to hospital with a 2-week history of behavioural changes and generalised seizures. A neurological examination showed short-term memory loss, confusion and aphasia. Electroencephalography showed slowing in the left temporal lobe. Magnetic resonance …

We analyzed neuromyelitis optica (NMO) IgG in the serum or CSF samples from 46 patients with suspected NMO (28) and limited forms of NMO (18). One hundred and fifteen samples from multiple sclerosis (MS) patients were included as controls. The final clinical diagnosis after follow-up was 16 NMO, 12 MS, 11 transverse myelitis (TM) and seven recurrent optic neuritis (RON). NMO-IgG was detected in 62.5% of NMO, 50% of the recurrent longitudinally extensive TM, 14.3% of the RON but in none of the MS patients. The authors then compared the newly revised diagnostic criteria for NMO with the criteria published in 1999, in the 28 patients with suspected NMO. The revised criteria had higher specificity, and positive and negative predictive value (83.3% vs. 25%; 87.5% vs. 62.5; 83.3% vs. 75%), but slightly lower sensitivity (87.5% vs. 93.7%). Our study confirms NMO-IgG as a highly specific marker of NMO, and the usefulness of the revised diagnostic criteria in predicting a diagnosis of NMO.

Diagnostic evaluation of two sisters affected by ataxia, with similar age of onset, revealed a characteristic trinucleotide expansion in the Friedreich’s ataxia (FRDA) locus and two different phenotypic presentations. At onset the elder sister had retained deep tendon reflexes (FARR), while the younger sister presented classic FRDA. The GAA expansion in the patients’ alleles proved to be similar in both siblings, ruling out that age at onset and clinical heterogeneity could be due to different FRDA mutations. On the whole, clinical and genetic data on these patients confirmed that FARR is a variant phenotype of FRDA.

Few adult patients present with an irreversible subacute cerebellar ataxia of unknown cause.1,2 The subacute evolution and the presence of CSF pleocytosis suggest a possible immune-mediated pathogenesis. In this study, we characterize the antigen of a new anti-Purkinje cell antibody identified in a patient with idiopathic subacute cerebellar ataxia.1,2 A 65-year-old woman presented in October 2000 with a week history of vertigo and vomiting. She denied symptoms of previous infectious disease. Neurologic examination revealed dysarthria, horizontal nystagmus, and severe limb and gait ataxia. Routine blood analysis, thyroid hormones, antineuronal antibodies (Hu, Yo, Ri, Ma1 and 2, CV2, Tr, GAD, and amphiphysin), brain MRI, colonoscopy, esophagogastroscopy, and CT of the chest and abdomen were normal or negative. CSF showed 27 lymphocytes/mm3 with a CSF IgG index of 1.4 (n < 0.7). She did not improve after treatment with steroids. At the last evaluation in June 2006, the cerebellar syndrome was unchanged with no cancer clinically evident. Immunohistochemistry was performed as described.3 Cerebellum samples from normal rats or mice and Homer 3–deficient mice (gift of Dr. Paul F. Worley) were subjected to standard immunoblot procedures.3 …