Mark Wardle

Contactin-associated protein-2 antibodies in non-paraneoplastic cerebellar ataxia

Background Relatively few studies have searched for potentially pathogenic antibodies in non-paraneoplastic patients with cerebellar ataxia. Methods and Results We first screened sera from 52 idiopathic ataxia patients for binding of serum IgG antibodies to cerebellar neurons. One strong-binding serum was selected for immunoprecipitation and mass spectrometry, which resulted in the identification of contactin-associated protein 2 (CASPR2) as a major antigen. CASPR2 antibodies were then found by a cell-based assay in 9/88 (10%) ataxia patients, compared to 3/144 (2%) multiple sclerosis or dementia controls (p=0.011). CASPR2 is strongly expressed in the cerebellum, only partly in association with voltage-gated potassium channels. Conclusions Prospective studies are now needed to see whether identification of CASPR2 antibodies has relevance for the diagnosis and treatment of idiopathic cerebellar ataxia.

SGCE mutations cause psychiatric disorders: clinical and genetic characterization

Myoclonus dystonia syndrome is a childhood onset hyperkinetic movement disorder characterized by predominant alcohol responsive upper body myoclonus and dystonia. A proportion of cases are due to mutations in the maternally imprinted SGCE gene. Previous studies have suggested that patients with SGCE mutations may have an increased rate of psychiatric disorders. We established a cohort of patients with myoclonus dystonia syndrome and SGCE mutations to determine the extent to which psychiatric disorders form part of the disease phenotype. In all, 89 patients with clinically suspected myoclonus dystonia syndrome were recruited from the UK and Ireland. SGCE was analysed using direct sequencing and for copy number variants. In those patients where no mutation was found TOR1A (GAG deletion), GCH1, THAP1 and NKX2-1 were also sequenced. SGCE mutation positive cases were systematically assessed using standardized psychiatric interviews and questionnaires and compared with a disability-matched control group of patients with alcohol responsive tremor. Nineteen (21%) probands had a SGCE mutation, five of which were novel. Recruitment of family members increased the affected SGCE mutation positive group to 27 of whom 21 (77%) had psychiatric symptoms. Obsessive-compulsive disorder was eight times more likely (P < 0.001) in mutation positive cases, compulsivity being the predominant feature (P < 0.001). Generalized anxiety disorder (P = 0.003) and alcohol dependence (P = 0.02) were five times more likely in mutation positive cases than tremor controls. SGCE mutations are associated with a specific psychiatric phenotype consisting of compulsivity, anxiety and alcoholism in addition to the characteristic motor phenotype. SGCE mutations are likely to have a pleiotropic effect in causing both motor and specific psychiatric symptoms.

Demographic and clinical factors associated with changes in employment in multiple sclerosis

Objective: The objective of this paper is to investigate demographic and disease factors associated with changes in employment role and status in multiple sclerosis (MS). Methods: Questionnaires on current symptoms, employment status and factors associated with changes in employment were sent to a community sample of 566 MS patients. Results: A total of 221 completed questionnaires were analysed. Of 169 employed at diagnosis, 43.3% had left employment at a mean of 11.9 years after disease onset. Of those still employed, 55% had changed their role or working hours to accommodate symptoms relating to their disease. These patients reported greater fatigue (p = 0.001), pain (p = 0.033) and memory problems (p = 0.038) than those whose employment had remained unaffected. Multinomial logistic regression revealed the factors most strongly predictive of employment status were disability level, years of education, disease duration and fatigue (p = 0.032). Conclusions: Despite changes to public perceptions and legislative protection over the last 20 years, high rates of MS patients still leave the workforce prematurely, reduce working hours or change employment roles. These data have significant implications when considering social and economic impacts of MS, support the value of employment metrics as long-term outcome measures, and demonstrate the need to improve employment requirements and flexibility of working practices in individuals with MS.

Long-term outcome of paediatric-onset multiple sclerosis: a population-based study

Background Age of onset of multiple sclerosis (MS) peaks in the 3rd and 4th decades and is rarely less than 18. Robust longitudinal studies in paediatric-onset MS (POMS) are limited, and a clearer understanding of outcome could optimise management strategies. Methods Patients with disease onset <18 years were identified from a prospective population-based register. Clinical features including presenting symptoms, time to Expanded Disability Status Scale (EDSS) 4.0, 6.0 and 8.0 and onset of secondary progression were compared with patients with adult-onset MS (AOMS). Results 111 POMS patients were identified from a cohort of 2068. No significant differences in sex ratio, familial recurrence, relapse rate, ethnicity or clinical symptoms at presentation were identified between POMS and AOMS. However, interval to second relapse was longer (5 vs 2.6 years, p=0.04) and primary progressive disease was less common (0.9% vs 8.5%, p=0.003) in POMS than in AOMS. POMS patients also took longer to develop secondary progressive disease (32 vs 18 years, p=0.0001) and to reach disability milestones (EDSS 4.0, 23.8 vs 15.5 years, p<0.0001; EDSS 6.0, 30.8 vs 20.4 years, p<0.0001; EDSS 8.0, 44.7 vs 39 years, p=0.02), but did so between 7.0 and 12 years younger than in AOMS. Conclusions 5.4% of patients with MS have POMS (2.7% <16 years; 0.3% <10 years) and have distinct phenotypic characteristics in early disease. Furthermore, while patients with POMS take longer to reach disability milestones, they do so at a younger age than their adult counterparts and could be considered to have a poorer prognosis. Management strategies for these patients should take account of these data.

Clinical and Genetic Characteristics of Non-Asian Dentatorubral-Pallidoluysian Atrophy: A Systematic Review

Dentatorubral‐pallidoluysian atrophy (DRPLA) is an inherited neurodegenerative disorder regarded as found almost exclusively among the Japanese. We have performed as systematic review of published literature to investigate the clinical and genetic characteristics of non‐Asian DRPLA. We identified 183 non‐Asian patients in 27 families reported with DRPLA with a variable level of clinical information. Mean age at onset was 31 (range 1–67) with epilepsy, ataxia, and chorea common presenting features. A highly significant relationship was identified between repeat length and age at onset with repeat length accounting for 62% of the observed variation in age at onset (P < 0.0001). In addition, a highly significant relationship between repeat length and main presenting complaint was identified (P < 0.001). There was evidence of marked anticipation with a median intergenerational reduction in age at onset of 19 years with a corresponding increase of five repeats per generation. DRPLA is not exclusively found among the Japanese but has been reported worldwide. As such, DRPLA should be considered in the differential diagnosis of a wide spectrum of neurological disease, particularly if there is a dominant family history. Non‐Asian DRPLA clinico‐genetic phenomenology are similar to Asian series and our study confirms marked genetic anticipation together with a clear association between repeat length and clinical phenotype and disease severity.

Alemtuzumab for multiple sclerosis: Long term follow-up in a multi-centre cohort:

Background: Alemtuzumab has recently been approved for treatment of relapsing MS, but concerns remain about its use since long-term studies of adverse events remain limited. Furthermore, a clear understanding of its application and durability of effect in clinical practice has yet to evolve. Objectives: To investigate long-term efficacy and safety outcomes in a multicentre cohort of patients treated with alemtuzumab. Methods: Patients treated from 2000 and followed-up at three regional centres were identified. Baseline and prospective data were obtained and validated by clinical record review. Results: One hundred patients were identified with a mean follow-up of 6.1 years (range 1–13). Forty patients were retreated with at least one further treatment cycle. Annualized relapse rates fell from 2.1 to 0.2 (p<0.0001) post-treatment and were sustained for up to eight years of follow-up. Mean change in EDSS score was +0.14. Forty-seven patients developed secondary autoimmunity. Conclusion: Observed reduction in relapse rates reflected those reported in clinical trials, but we were unable to corroborate previous observations of disability reversal. 40% of patients required additional treatment cycles. Autoimmune adverse events were common, occurring at a higher rate than previously reported, but were largely predictable, and could be managed effectively within a rigorous monitoring regime.

Modelling the natural history of primary progressive multiple sclerosis

Background A minority of patients with multiple sclerosis (MS) have primary progressive disease (PPMS). Treatment options are currently limited, but as prospects for interventional studies become more realistic, understanding contemporary outcome data will be key to successful trial design. Methods 234 PPMS patients were identified from a population-based cohort of 2131 (11.0%) and mean follow-up of 13.1 years. Time to established disability endpoints was compared with patients with relapsing-onset MS (ROMS) using survival analysis, and Cox regression employed to explore factors contributing to disability accumulation. Results were used to create predictive power models for clinical trials in PPMS. Results Time to fixed disability milestones was shorter than in ROMS (Expanded Disability Status Scale (EDSS) 4.0:8.1 vs 17.1 years, p<0.001; EDSS 6.0: 9.6 vs 22.1 years, p<0.001; EDSS 8.0: 20.7 vs 39.7 years, p<0.001), but there were no differences in age-related disability. Age and cerebellar symptoms at onset affected rate of progression. Modelling of these data indicated that trials employing EDSS change of 1.0 as the primary outcome measure would be powered to detect a 20% difference in progression using 600 patients with initial EDSS of 4.0 per trial arm, or 400 patients with initial EDSS of 5.0 per arm. However, trials including patients with fixed EDSS of ≥6.0 will be underpowered even with large numbers or prolonged duration. Conclusions Disability progression in PPMS is variable and influenced by age at onset. Although progression is more rapid, age-related disability milestones are identical to relapsing-onset disease. These data offer a contemporary paradigm for clinical trial design in progressive MS.

The genetic aetiology of late-onset chronic progressive cerebellar ataxia

BackgroundAn increasing number of dominant and recessive disorders have been associated with late onset chronic progressive ataxia (LOCA) complicating the formulation of a rational diagnostic strategy. Furthermore, there is marked geographic and ethnic variation in the relative importance of these individual disorders and the cause of such observed variation remains unexplained.MethodsWe have systematically investigated a populationbased cohort of patients with chronic progressive LOCA for SCA 1,2,3,6,7,8,10,12,17, FXTAS and FRDA. In addition we have examined repeat length polymorphism in chromosomes from a genetically homogeneous and representative control population to investigate the association of high-normal repeats and disease prevalence.ResultsA total of 178 patients including 55 familial cases segregating in 38 kindreds and 123 sporadic were investigated. Pathological expansions were identified in 11/38 (28.9 %) of families and in 5/123 (4.1 %) of sporadic patients. The most frequent diagnoses were SCA6 (6 families and 1 sporadic patient), DRPLA (4 families) and SCA8 (1 family). In addition, one elderly female patient was identified with “possible FXTAS”. Six (2 %) control patients were noted to have expanded SCA8 alleles.ConclusionsSCA6 and DRPLA were the most frequent genetic diagnoses identified. Patterns of highnormal allele frequency in this UK population were distinct compared to other ethnic groups but this was poorly predictive of the distribution of disease in this region. The relative contribution of new mutation formation and founder effects to the prevalence of familial ataxia is uncertain, and further exploration of these factors will require detailed analysis of disease allele haplotypes and meiotic instability of intermediate length alleles.

Dentatorubral pallidoluysian atrophy in South Wales

Background: Dentatorubral pallidoluysian atrophy (DRPLA) is a rare, autosomal dominant, clinically heterogeneous neurodegenerative disorder characterised clinically by progressive dementia, ataxia, chorea, myoclonic epilepsy and psychiatric disturbance and pathologically by combined degeneration of the dentatorubral and pallidoluysian systems. DRPLA has a marked ethnic predilection, most commonly reported in Japan and thought to be rare in Caucasian populations. Methods: We describe the clinical and genetic characteristics of 17 patients with DRPLA segregating in four families in South Wales. Results: There was marked clinical heterogeneity with considerable overlap of symptoms and signs between and within families. The age of onset ranged from 34 to 60 years with an earlier onset associated with myoclonic epilepsy and a later onset associated with a Huntington disease-like presentation. We identified a distinct haplotype within one family not present within the other three families, suggesting that the expansion in at least one family did not arise from an immediate common ancestor. Analysis of repeat length polymorphisms in 306 Welsh control patients identified 14 (4.6%) with repeat lengths in the high-normal range, compared with 0% and 7.4% in previously reported north American Caucasian and Japanese control populations, respectively. Conclusions: DRPLA may not be as geographically or ethnically restricted as previously thought and the diagnosis should be considered in non-Asian patients presenting with a wide spectrum of neurological disease, especially if there is a dominant family history of dementia or movement disorder. The prevalence of high-normal length alleles may account for the relatively high prevalence of DRPLA in Wales.

Case control analysis of repeat expansion size in ataxia

Spinocerebellar ataxias (SCAs) are a group of clinically and genetically heterogeneous neurological diseases. The expansion of unstable microsatellite repeats has been identified as the underlying pathogenic cause of 10 subtypes of autosomal dominant SCAs. The aetiology of sporadic SCA is unknown. The aim of this study was to investigate the effect of large normal repeats in patients presenting with sporadic or familial ataxia compared to a control population. The size of the expansion was determined using a fluorescent PCR approach in 10 common SCA genes: SCA-1 (ATXN1), SCA-2 (ATXN2), SCA-3 (ATXN3), SCA-6 (CACNA1A), SCA-7 (ATXN7), SCA-8 (ATXN8OS), SCA-10 (ATXN10), SCA-12 (PPP2R2B), SCA-17 (TBP) and DRPLA (ATN1), in 165 ataxia patients and 307 controls of Welsh origin. There was no difference between cases and controls in the distribution of the large normal alleles, or in the distribution of the combined CAG repeats. The normal allele distribution in the Welsh population was largely similar to that of other Caucasian populations. Our study failed to demonstrate an effect of large normal repeats on the susceptibility to develop ataxia.