Monogenic cerebral small-vessel diseases: diagnosis and therapy. Consensus recommendations of the European Academy of Neurology.

BACKGROUND AND PURPOSE: Guidelines on monogenic cerebral small-vessel disease (cSVD) diagnosis and management are lacking. Endorsed by the Stroke and Neurogenetics Panels of the European Academy of Neurology, a group of experts has provided recommendations on selected monogenic cSVDs, i.e. cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), autosomal dominant High Temperature Requirement A Serine Peptidase 1 (HTRA1), cathepsin-A-related arteriopathy with strokes and leukoencephalopathy (CARASAL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), Fabry disease, mitochondrial encephalopathy, lactic acidosis and stroke-like episodes (MELAS) and type IV collagen (COL4)A1/2. METHODS: We followed the Delphi methodology to provide recommendations on several unanswered questions related to monogenic cSVD, including genetic testing, clinical and neuroradiological diagnosis, and management. RESULTS: We have proposed 'red-flag' features suggestive of a monogenic disease. General principles applying to the management of all cSVDs and specific recommendations for the individual forms of monogenic cSVD were agreed by consensus. CONCLUSIONS: The results provide a framework for clinicians involved in the diagnosis and management of monogenic cSVD. Further multicentre observational and treatment studies are still needed to increase the level of evidence supporting our recommendations.

The complex phenotype of spinocerebellar ataxia type 48 in eight unrelated Italian families.

BACKGROUND AND PURPOSE: Heterozygous mutations in the STUB1 gene have recently been associated with an autosomal dominant form of spinocerebellar ataxia (SCA) associated with cerebellar cognitive-affective syndrome (CCAS), named SCA48. METHODS: Molecular screening was performed in a cohort of 235 unrelated patients with adult-onset, autosomal dominant (17) or sporadic (218) cerebellar ataxia, negative for pathological trinucleotide expansions in the common SCAs, FRDA and FXTAS loci, by using targeted multigene panels or whole-exome sequencing. Bioinformatics analyses, detailed neurological phenotyping and family segregation studies corroborated the pathogenicity of the novel STUB1 mutations. Clinico-diagnostic findings were reviewed to define the phenotypic spectrum. RESULTS: Eight heterozygous STUB1 mutations were identified, six of which were novel in 11 patients from eight index families, giving an estimated overall frequency of 3.4% (8/235) for SCA48 in our study cohort, rising to 23.5% (4/17) when considering only familial cases. All our SCA48 patients had cerebellar ataxia and dysarthria associated with cerebellar atrophy on brain magnetic resonance imaging; of note, many cases were also associated with parkinsonism, chorea and dystonia. CCAS also occurred frequently, whereas definite signs of pyramidal tract dysfunction and peripheral nervous system involvement were absent. One SCA48 patient presented with hypogonadism, associated with other autoimmune endocrine dysfunctions. CONCLUSIONS: Our results support SCA48 as a significant cause of adult-onset SCA. Besides CCAS, our SCA48 patients often showed movement disorders and other clinical manifestations previously described in SCAR16, linked to biallelic variants in the same gene, thus suggesting a continuous clinical spectrum and significant overlap amongst recessive and dominantly inherited mutations in STUB1.

The Working Life of People with Degenerative Cerebellar Ataxia.

The aim of the present study was to characterize and analyze the most important individual and organizational variables associated with job accommodation in subjects with degenerative cerebellar ataxia by administering a series of international and validated work activity-related scales. Twenty-four workers (W) and 58 non-workers (NW) were recruited: 34 with autosomal dominant ataxia and 48 with autosomal recessive ataxia (27 with Friedreich ataxia and 21 with sporadic adult-onset ataxia of unknown etiology). The severity of ataxia was rated using the Scale for the Assessment and Rating of Ataxia. Our results showed that the ataxic W were predominantly middle-aged (41-50 years), high school graduate, and married men with a permanent work contract, who had been working for more than 7 years. The W with ataxia exhibited a good level of residual working capacity, irrespective of gender, age range, and duration of the disease, and they were observed to have a low or average-to-low job stress-related risk. Supporting patients with ataxia to find an appropriate job is an important priority because about 78% of NW search for a job and W and NW have the same potential work abilities (no relevant differences were found in terms of disease characteristics, gender, and work resilience). In this view, introducing NW to work-life may have a potential rehabilitative aspect. Findings of this study highlight that equal job opportunities for subjects affected by cerebellar ataxia are recommended.

Prevalence and phenotype of the c.1529C>T SPG7 variant in adult-onset cerebellar ataxia in Italy.

BACKGROUND AND PURPOSE: Hereditary ataxias are heterogeneous groups of neurodegenerative disorders, characterized by cerebellar syndromes associated with dysarthria, oculomotor and corticospinal signs, neuropathy and cognitive impairment. Recent reports have suggested mutations in the SPG7 gene, causing the most common form of autosomal recessive spastic paraplegia (MIM#607259), as a main cause of ataxias. The majority of described patients were homozygotes or compound heterozygotes for the c.1529C>T (p.Ala510Val) change. We screened a cohort of 895 Italian patients with ataxia for p.Ala510Val in order to define the prevalence and genotype-phenotype correlation of this variant. METHODS: We set up a rapid assay for c.1529C>T using restriction enzyme analysis after polymerase chain reaction amplification. We confirmed the diagnosis with Sanger sequencing. RESULTS: We identified eight homozygotes and 13 compound heterozygotes, including two novel variants affecting splicing. Mutated patients showed a pure cerebellar ataxia at onset, evolving in mild spastic ataxia (alternatively) associated with dysarthria (~80% of patients), urinary urgency (~30%) and pyramidal signs (~70%). Comparing homozygotes and compound heterozygotes, we noted a difference in age at onset and Scale for the Assessment and Rating of Ataxia score between the two groups, supporting an earlier and more severe phenotype in compound heterozygotes versus homozygotes. CONCLUSIONS: The SPG7 c.1529C>T (p.Ala510Val) mutants accounted for 2.3% of cerebellar ataxia cases in Italy, suggesting that this variant should be considered as a priority test in the presence of late-onset pure ataxia. Moreover, the heterozygous/homozygous genotype appeared to predict the onset of clinical manifestation and disease progression.

SPG5 and multiple sclerosis: clinical and genetic overlap?

BACKGROUND: Autosomal recessive (AR) spastic paraplegia type 5 (SPG5) is due to mutations in the CYP7B1 gene, encoding for the cytochrome P450-7B1, responsible for oxysterols 7α-hydroxylation. Oxysterol/cholestenoic acids pool plays a role in motor neuron survival and immune response. SPG5 is characterized by white matter abnormalities at brain resonance imaging (MRI). In view of clinical presentation and MRI findings, multiple sclerosis (MS) is a possible differential diagnosis of SPG5. This study aimed to evaluate the frequency of CYP7B1 mutations in patients with MS. METHODS: One hundred and seventeen MS patients with clinical spastic paraplegia or possible AR transmission were selected for the mutational screening. RESULTS: Forty-three patients had primary progressive, 26 relapsing remitting, 26 secondary progressive, and 22 relapsing progressive MS clinical course. No CYP7B1 homozygous mutations were identified. Two novel variants and one pathogenic mutation were found at heterozygous state. CONCLUSIONS: The two novel variants cosegregated with pyramidal signs and autoimmune diseases suggesting that they might be susceptibility factors. Reduced cytochrome P450-7B1 enzymatic activity could alter the balance among neurotoxic and neuroprotective oxysterols promoting motor neuron degeneration and/or immune response.

Powerhouse failure and oxidative damage in autosomal recessive spastic ataxia of Charlevoix-Saguenay.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a neurodegenerative disease due to mutations in SACS, which encodes sacsin, a protein localized on the mitochondrial surface and possibly involved in mitochondrial dynamics. In view of the possible mitochondrial involvement of sacsin, we investigated mitochondrial activity at functional and molecular level in skin fibroblasts obtained from ARSACS patients. We observed remarkable bioenergetic damage in ARSACS cells, as indicated by reduced basal, adenosine triphosphate (ATP)-linked and maximal mitochondrial respiration rate, and by reduced respiratory chain activities and mitochondrial ATP synthesis. These phenomena were associated with increased reactive oxygen species production and oxidative nuclear DNA damage. Our results suggest that loss of sacsin is associated with oxidative stress and mitochondrial dysfunction, and thus highlight a novel mechanism in the pathogenesis of ARSACS. The involvement of mitochondria and oxidative stress in disease pathogenesis has been described in a number of other neurodegenerative diseases. Therefore, on the basis of our findings, which suggest a potential therapeutic role for antioxidant agents, ARSACS seems to fall within a larger group of disorders.

Metabolic Ataxias in Adults.

Metabolic ataxias are rare. They usually start in the childhood and often have autosomal recessive inheritance. They may also present in adulthood. The diagnosis is important since some patients may be successfully managed with diet and treatments.

Inventory of Non-Ataxia Signs (INAS): validation of a new clinical assessment instrument.

Although ataxia is by definition the prominent symptom of ataxia disorders, there are various neurological signs that may accompany ataxia in affected patients. Reliable and quantitative assessment of these signs is important because they contribute to disability, but may also interfere with ataxia. Therefore we devised the Inventory of Non-Ataxia Signs (INAS), a list of neurological signs that allows determining the presence and severity of non-ataxia signs in a standardized way. INAS underwent a rigorous validation procedure that involved a trial of 140 patients with spinocerebellar ataxia (SCA) for testing of inter-rater reliability and another trial of 28 SCA patients to assess short-term intra-rater reliability. In addition, data of the ongoing EUROSCA natural history study were used to determine the reproducibility, responsiveness and validity of INAS. Inter-rater reliability and short-term test-retest reliability was high, both for the total count and for most of the items. However, measures of responsiveness, such as the smallest detectable change and the clinically important change were not satisfactory. In addition, INAS did not differentiate between subjects that were subjectively stable and those that worsened in the 2-year observation period. In summary, INAS and INAS count showed good reproducibility, but unsatisfactory responsiveness. The present analysis and published data from the EUROSCA natural history study suggest that INAS is a valid measure of extracerebellar involvement in progressive ataxia disorders. As such, it is useful as a supplement to the measures of ataxia, but not as a primary outcome measure in future interventional trials.

The natural history of spinocerebellar ataxia type 1, 2, 3, and 6: a 2-year follow-up study.

OBJECTIVE: To obtain quantitative data on the progression of the most common spinocerebellar ataxias (SCAs) and identify factors that influence their progression, we initiated the EUROSCA natural history study, a multicentric longitudinal cohort study of 526 patients with SCA1, SCA2, SCA3, or SCA6. We report the results of the 1- and 2-year follow-up visits. METHODS: As the primary outcome measure we used the Scale for the Assessment and Rating of Ataxia (SARA, 0-40), and as a secondary measure the Inventory of Non-Ataxia Symptoms (INAS, 0-16) count. RESULTS: The annual increase of the SARA score was greatest in SCA1 (2.18 ± 0.17, mean ± SE) followed by SCA3 (1.61 ± 0.12) and SCA2 (1.40 ± 0.11). SARA progression in SCA6 was slowest and nonlinear (first year: 0.35 ± 0.34, second year: 1.44 ± 0.34). Analysis of the INAS count yielded similar results. Larger expanded repeats and earlier age at onset were associated with faster SARA progression in SCA1 and SCA2. In SCA1, repeat length of the expanded allele had a similar effect on INAS progression. In SCA3, SARA progression was influenced by the disease duration at inclusion, and INAS progression was faster in females. CONCLUSIONS: Our study gives a comprehensive quantitative account of disease progression in SCA1, SCA2, SCA3, and SCA6 and identifies factors that specifically affect disease progression.

Myelinated retinal fibers in autosomal recessive spastic ataxia of Charlevoix-Saguenay.

BACKGROUND: Myelinated retinal nerve fibers are considered a hallmark of autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) in French Canadian patients. The demonstration of a worldwide distribution of this disease, as well as the almost invariable presence of a normal retina on fundoscopy in cases outside Canada, suggests that more quantitative methodologies are needed to assess the retina in ARSACS. METHODS: To characterize better the retinal features of ARSACS, we studied five Italian patients by means of optical coherence tomography (OCT), a processing method that allows the creation of three-dimensional images with micrometer resolution. We compared OCT characteristics in ARSACS with those obtained from five subjects with persistent myelination of the retina, a rare congenital non-progressive anomaly. RESULTS: Four patients with ARSACS showed myelinated retinal nerve fibers on ophthalmoscopy, corresponding to an increased thickness of the retina on OCT, a characteristic not present in the subjects with persistent myelination of the retina. CONCLUSIONS: Myelinated retinal fibers are not rare in Italian patients with ARSACS. This finding may be the consequence of the thickening of the retina, as detected by OCT.

Responsiveness of different rating instruments in spinocerebellar ataxia patients.

OBJECTIVE: To determine the longitudinal metric properties of recently developed clinical assessment tools in spinocerebellar ataxia (SCA). METHODS: A subset of 171 patients from the EUROSCA natural history study cohort (43 SCA1, 61 SCA2, 37 SCA3, and 30 SCA6) were examined after 1 year of follow-up. Score changes and effect size indices were calculated for clinical scales (Scale for the Assessment and Rating of Ataxia [SARA], Inventory of Non-Ataxia Symptoms [INAS]), functional tests (SCA Functional Index [SCAFI] and components), and a patient-based scale for subjective health status (EQ-5D visual analogue scale [EQVAS]). Responsiveness was determined in relation to the patient's global impression (PGI) of change and reproducibility described as retest reliability for the stable groups and smallest detectable change. RESULTS: Within the 1-year follow-up period, SARA, INAS, and SCAFI but not EQVAS indicated worsening in the whole group and in the groups with subjective (PGI) worsening. SCAFI and its 9-hole pegboard (9HPT) component also deteriorated in the stable groups. Standardized response means were highest for 9HPT (-0.67), SARA (0.50), and SCAFI (-0.48) with accordingly lower sample size estimates of 143, 250, or 275 per group for a 2-arm interventional trial that aims to reduce disease progression by 50%. SARA and EQVAS performed best to distinguish groups classified as worse by PGI. All scales except EQVAS reached the criterion for retest reliability. CONCLUSION: While both the Scale for the Assessment and Rating of Ataxia and the SCA Functional Index (SCAFI) (and its 9-hole pegboard component) had favorable measurement precision, the clinical relevance of SCAFI and 9-hole pegboard score changes warrants further exploration. The EQ-5D visual analogue scale proved insufficient for longitudinal assessment, but validly reflected patients' impression of change.

Low-dose idebenone treatment in Friedreich's ataxia with and without cardiac hypertrophy.

Left ventricular hypertrophy (LVH) is a frequent finding in Friedreich's ataxia (FRDA). In previous studies treatment with idebenone, a synthetic analogue of coenzyme Q10, has been associated with a substantial decrease in myocardial hypertrophy, despite great variability in cardiac responsiveness among patients. Here we present the results of a retrospective analysis of a cohort of 35 patients (20 with LVH, 15 without LVH) with confirmed molecular diagnosis of FRDA, treated with idebenone 5 mg/kg/day for up to five years. At the end of the study, we found an increase of interventricular septum and posterior wall thickness in the group without LVH before treatment and no change in the group with LVH before treatment. The neurological picture of the disease significantly deteriorated with time in both groups.

Autonomic nervous system abnormalities in spinocerebellar ataxia type 2: a cardiovascular neurophysiologic study.

Autonomic nervous system dysfunction is part of the spinocerebellar ataxia (SCA) clinical picture, but few data are available on this topic. The present study is aimed to report a detailed investigation of autonomic nervous system in patients with molecular diagnosis of SCA type 2, one of the most frequent forms and the commonest in Italy. Nine patients with a mild to moderate form of SCA2 underwent a questionnaire about dysautonomic symptoms and a complete cardiovascular neurophysiologic evaluation of both sympathetic and parasympathetic system, comprising head-up tilt, standing, isometric hand grip, cold pressure, mental arithmetic, Valsalva manoeuvre, deep breathing, and hyperventilation tests. An echocardiographic study and Holter-ECG recording were also performed. All patients complained dysautonomic problems regarding urinary tract, cardiovascular system, or gastrointestinal dysfunction. The neurophysiologic study showed both sympathetic and parasympathetic involvement, with highly variable degree and pattern of dysautonomia. The present study results show that the autonomic dysfunction is common in SCA2 representing a significant component of the complex picture of the disease. We found a wide spectrum of cardiovascular autonomic abnormalities, without a typical pattern of dysfunction and without correlation with clinical variables.

Spinocerebellar ataxia types 1, 2, 3, and 6: disease severity and nonataxia symptoms.

OBJECTIVE: To identify factors that determine disease severity and clinical phenotype of the most common spinocerebellar ataxias (SCAs), we studied 526 patients with SCA1, SCA2, SCA3. or SCA6. METHODS: To measure the severity of ataxia we used the Scale for the Assessment and Rating of Ataxia (SARA). In addition, nonataxia symptoms were assessed with the Inventory of Non-Ataxia Symptoms (INAS). The INAS count denotes the number of nonataxia symptoms in each patient. RESULTS: An analysis of covariance with SARA score as dependent variable and repeat lengths of the expanded and normal allele, age at onset, and disease duration as independent variables led to multivariate models that explained 60.4% of the SARA score variance in SCA1, 45.4% in SCA2, 46.8% in SCA3, and 33.7% in SCA6. In SCA1, SCA2, and SCA3, SARA was mainly determined by repeat length of the expanded allele, age at onset, and disease duration. The only factors determining the SARA score in SCA6 were age at onset and disease duration. The INAS count was 5.0 +/- 2.3 in SCA1, 4.6 +/- 2.2 in SCA2, 5.2 +/- 2.5 in SCA3, and 2.0 +/- 1.7 in SCA6. In SCA1, SCA2, and SCA3, SARA score and disease duration were the strongest predictors of the INAS count. In SCA6, only age at onset and disease duration had an effect on the INAS count. CONCLUSIONS: Our study suggests that spinocerebellar ataxia (SCA) 1, SCA2, and SCA3 share a number of common biologic properties, whereas SCA6 is distinct in that its phenotype is more determined by age than by disease-related factors.

SCA Functional Index: a useful compound performance measure for spinocerebellar ataxia.

OBJECTIVE: To evaluate the usefulness of functional measures in patients with spinocerebellar ataxia (SCA). METHODS: We assessed three functional measures-8 m walking time (8MW), 9-hole peg test (9HPT), and PATA repetition rate-in 412 patients with autosomal dominant SCA (genotypes 1, 2, 3, and 6) in a multicenter trial. RESULTS: While PATA rate was normally distributed (mean/median 21.7/20.5 per 10 s), the performance times for 8MW (mean/median 10.8/7.5 s) or 9HPT (mean/median 47.2/35.0 s in dominant, 52.2/37.9 s in nondominant hand) were markedly skewed. Possible learning effects were small and likely clinically irrelevant. A composite functional index (SCAFI) was formed after appropriate transformation of subtest results. The Z-scores of each subtest correlated well with the Scale for the Assessment and Rating of Ataxia (SARA), the Unified Huntington's disease Rating Scale functional assessment, and disease duration. Correlations for SCAFI with each of these parameters were stronger (Pearson r = -0.441 to -0.869) than for each subtest alone. Furthermore, SCAFI showed a linear decline over the whole range of disease severity, while 9HPT and 8MW had floor effects with respect to SARA. Analysis of possible confounders showed no effect of genotype or study site and only minor effects of age for 8MW. CONCLUSION: The proposed functional measures and their composite SCAFI have favorable properties to assess patients with spinocerebellar ataxia.

DNA methylation in intron 1 of the frataxin gene is related to GAA repeat length and age of onset in Friedreich ataxia patients.

BACKGROUND: The most frequent mutation of Friedreich ataxia (FRDA) is the abnormal expansion of a GAA repeat located within the first intron of FXN gene. It is known that the length of GAA is directly correlated with disease severity. The effect of mutation is a severe reduction of mRNA. Recently, a link among aberrant CpG methylation, chromatin organisation and GAA repeat was proposed. METHODS: In this study, using pyrosequencing technology, we have performed a quantitative analysis of the methylation status of five CpG sites located within the region upstream of GAA repeat, in 67 FRDA patients. RESULTS: We confirm previous observation about differences in the methylation degree between FRDA individuals and controls. We showed a direct correlation between CpG methylation and triplet expansion size. Significant differences were found for each CpG tested (ANOVA p<0.001). These differences were largest for CpG1 and CpG2: 84.45% and 76.80%, respectively, in FRDA patients compared to 19.65% and 23.34% in the controls. Most importantly, we found a strong inverse correlation between CpG2 methylation degree and age of onset (Spearman's rho = -0.550, p<0.001). CONCLUSION: Because epigenetic changes may cause or contribute to gene silencing, our data may have relevance for the therapeutic approach to FRDA. Since the analysis can be performed in peripheral blood leucocytes (PBL), evaluation of the methylation status of specific CpG sites in FRDA patients could be a convenient biomarker.

Cervico-oculo-Acoustic syndrome in a male with consanguineous parents.

BACKGROUND: The cervico-oculo-acoustic syndrome comprises Klippel-Feil anomaly, sensorineural deafness and Duane's retraction syndrome. Polygenic, autosomal dominant, and X-linked inheritance have been hypothesized. The disorder has rarely been reported in males. CASE REPORT: A 42-year-old male, born of consanguineous parents, presented with Duane's syndrome, mixed hearing loss, C2-C3 fusion, neck stiffness, and right facial palsy. A variety of cardiac, neurological and urogenital anomalies occurred in his relatives. The electro-oculographic studies showed impaired abduction and adduction of the right eye and impaired abduction of the left eye. Vergence, vertical eye movements and peripheral vestibular responses were normal. Somatosensory evoked potentials showed absence of the N13 peak and brainstem auditory evoked potentials bilateral delay of the I-III interpeak latencies. CONCLUSIONS: Consanguinity of the patient's parents, not previously reported, suggests autosomal recessive inheritance, but autosomal dominant inheritance is indicated by the family history. The pattern of the oculomotor deficit is consistent with bilateral dysplasia of the abducens nuclei with preserved internuclear neurons in the right abducens nucleus. Neurophysiological investigations revealed lower brainstem and cervical cord involvement.