Epidemiology of Huntington disease: first post-HTT gene analysis of prevalence in Italy.

Huntington disease (HD) prevalence shows geographic variability and has been recently updated by taking into account the mutation diagnostic test. In Italy, the last epidemiological estimation was reported well before the HTT gene discovery and the availability of the corresponding genetic test. It reported a prevalence of affected subjects ranging between 2.3 and 4.8/100,000 in some restricted areas of Northern Italy. We have performed a service-based epidemiological analysis in a very restricted geographic area named Molise, where our institutions currently operate and represent the only point of reference for rare neuropsychiatric diseases. The estimated prevalence rate found was 10.85/100,000 (95% confidence interval (CI): 7.20-14.50), remarkably higher than that previously described before the gene test analysis was available, and expected to an increase of an additional 17% by 2030, because of Italian population aging. According to our analysis, we estimate that about 6500 subjects are currently affected by HD in Italy, and that this number will further increase in the next decades because of population aging, variable phenotype penetrance and improved life expectancy.

The Corticospinal Tract in Huntington's Disease.

Huntington's disease (HD) is characterized by progressive motor impairment. Therefore, the connectivity of the corticospinal tract (CST), which is the main white matter (WM) pathway that conducts motor impulses from the primary motor cortex to the spinal cord, merits particular attention. WM abnormalities have already been shown in presymptomatic (Pre-HD) and symptomatic HD subjects using magnetic resonance imaging (MRI). In the present study, we examined CST microstructure using diffusion tensor imaging (DTI)-based tractography in 30-direction DTI data collected from 100 subjects: Pre-HD subjects (n = 25), HD patients (n = 25) and control subjects (n = 50), and T2*-weighted (iron sensitive) imaging. Results show decreased fractional anisotropy (FA) and increased axial (AD), and radial diffusivity (RD) in the bilateral CST of HD patients. Pre-HD subjects had elevated iron in the left CST, regionally localized between the brainstem and thalamus. CAG repeat length in conjunction with age, as well as motor (UHDRS) assessment were correlated with CST FA, AD, and RD both in Pre-HD and HD. In the presymptomatic phase, increased iron in the inferior portion supports the "dying back" hypothesis that axonal damage advances in a retrograde fashion. Furthermore, early iron alteration may cause a high level of toxicity, which may contribute to further damage.

MRI measures of corpus callosum iron and myelin in early Huntington's disease.

Increased iron in subcortical gray matter (GM) structures of patients with Huntington's disease (HD) has been suggested as a causal factor in neuronal degeneration. But how iron content is related to white matter (WM) changes in HD is still unknown. For example, it is not clear whether WM changes share the same physiopathology (i.e. iron accumulation) with GM or whether there is a different mechanism. The present study used MRI to examine iron content in premanifest gene carriers (PreHD, n = 25) and in early HD patients (n = 25) compared with healthy controls (n = 50). 3T MRI acquisitions included high resolution 3D T1, EPI sequences for diffusion tensor imaging (DTI) as an indirect measure of tissue integrity, and T2*-weighted gradient echo-planar imaging for MR-based relaxometry (R2*), which provides an indirect measure of ferritin/iron deposition in the brain. Myelin breakdown starts in the PreHD stage, but there is no difference in iron content values. Iron content reduction manifests later, in the early HD stage, in which we found a lower R2* parameter value in the isthmus. The WM iron reduction in HD is temporally well-defined (no iron differences in PreHD subjects and iron differences only in early HD patients). Iron level in callosal WM may be regarded as a marker of disease state, as iron does not differentiate PreHD subjects from controls but distinguishes between PreHD and HD.

Multimodal MRI analysis of the corpus callosum reveals white matter differences in presymptomatic and early Huntington's disease.

Recent magnetic resonance imaging (MRI) studies suggest that abnormalities in Huntington's disease (HD) extend to white matter (WM) tracts in early HD and even in presymptomatic stages. Thus, changes of the corpus callosum (CC) may reflect various aspects of HD pathogenesis. We recruited 17 HD patients, 17 pre-HD subjects, and 34 healthy age-matched controls. Three-dimensional anatomical MRI and diffusion tensor images of the brain were acquired on a 3T scanner. Combining region-of-interest analyses, voxel-based morphometry, and tract-based spatial statistics, we investigated callosal thickness, WM density, fractional anisotropy, and radial and axial diffusivities. Compared with controls, pre-HD subjects showed reductions of the isthmus, likely due to myelin damage. Compared with pre-HD subjects, HD patients showed reductions of isthmus and body, with axonal damage confined to the body. Compared with controls, HD patients had significantly decreased callosal measures in extended regions across almost the entire CC. At this disease stage, both myelin and axonal damage are detectable. Supplementary multiple regression analyses revealed that WM reduction density in the isthmus as well as Disease Burden scores allowed to predict the "HD development" index. While callosal changes seem to proceed in a posterior-to-anterior direction as the diseases progresses, this observation requires validation in future longitudinal investigations.

Molecular analysis of new mutations for Huntington's disease: intermediate alleles and sex of origin effects.

Huntington's disease (HD) is associated with expansion of a CAG repeat in a novel gene. We have assessed 21 sporadic cases of HD to investigate sequential events underlying HD. We show the existence of an intermediate allele (IA) in parental alleles of 30-38 CAG repeats in the HD gene which is greater than usually seen in the general population but below the range seen in patients with HD. These IAs are meiotically unstable and in the sporadic cases, expand to the full mutation associated with the phenotype of HD. This expansion has been shown to occur only during transmission through the male germline and is associated with advanced paternal age. These findings suggest that new mutations for HD are more frequent than prior estimates and indicate a previously unrecognized risk of inheriting HD to siblings of sporadic cases of HD and their children.

The relationship between trinucleotide (CAG) repeat length and clinical features of Huntington's disease.

Huntington's disease (HD) is associated with the expansion of a CAG trinucleotide repeat in a novel gene. We have assessed 360 HD individuals from 259 unrelated families and found a highly significant correlation (r = 0.70, p = 10(-7)) between the age of onset and the repeat length, which accounts for approximately 50% of the variation in the age of onset. Significant associations were also found between repeat length and age of death and onset of other clinical features. Sib pair and parent-child analysis revealed that the CAG repeat demonstrates only mild instability. Affected HD siblings had significant correlations for trinucleotide expansion (r = 0.66, p < 0.001) which was not apparent for affected parent-child pairs.

Four novel SPG3A/atlastin mutations identified in autosomal dominant hereditary spastic paraplegia kindreds with intra-familial variability in age of onset and complex phenotype.

Mutation of the atlastin gene (SPG3A) is responsible for approximately 10% of autosomal dominant hereditary spastic paraplegia (AD-HSP) cases. The goal of this study was to identify novel disease causing atlastin mutations. Atlastin nucleotide variations were detected by direct sequencing of all 14 exons in 70 autosomal dominant (AD), 16 single sibship and 14 sporadic spastic paraplegia patients. Six mis-sense mutations (four of which were novel) were identified in six unrelated AD-HSP kindreds in exons 4, 7 and 8 of the atlastin gene. One kindred with a novel mutation showed variability in clinical phenotype and age of onset. Mutations are predicted to decrease GTPase activity, cause morphological abnormalities of the endoplasmic reticulum and prevent maturation of the Golgi complex resulting in impaired vesicle trafficking. Our study significantly adds to the spectrum of mutations and clinical phenotype of SPG3A. We advocate that all spastin mutation negative AD-HSP kindreds should be screened for pathogenic atlastin mutations regardless of age of onset or phenotypic complexity.

Emotional processing in RRMS patients: Dissociation between behavioural and neurophysiological response.

BACKGROUNG: Multiple sclerosis (MS) results in a broad range of symptoms, including motor, visual, cognitive, and neuropsychiatric deficits. Some studies, considering affective facial expressions to study emotion processing, demonstrated emotion recognition difficulties in MS patients. OBJECTIVE: We investigated the impact of MS on the emotional-behaviour rating and neurophysiological response (Event Related Potentials-ERP) through a battery of affective visual stimuli selected from the International Affective Picture System (IAPS). METHODS: Twenty patients with diagnosis of Relapsing Remitting MS (RRMS) and 20 Healthy Controls (HC) matched by age, gender and education were enrolled. Each of them, after a neuropsychological assessment, were asked to evaluate arousal and valence of affective visual stimuli. RESULTS: Our results showed higher P300 amplitudes in RRMS patients than HC group for pleasant and unpleasant images. Moreover, RRMS patients showed lower Reaction Time (RT) respect HC in valence rating. No other effect did emerge between groups. CONCLUSION: Our study shows early compensatory cerebral mechanisms in RRMS patients throughout emotional information processing, particularly for unpleasant and pleasant stimuli. We hypothesize that this compensatory cerebral mechanism reduces the behavioural dissimilarity between patients and HC.

ZPLD1 gene is disrupted in a patient with balanced translocation that exhibits cerebral cavernous malformations.

The past few years have seen rapid advances in our understanding of the genetics and molecular biology of cerebral cavernous malformations (CCM) with the identification of the CCM1, CCM2, and CCM3 genes. Recently, we have recruited a patient with an X/3 balanced translocation that exhibits CCM. By fluorescent in situ hybridization analysis, sequence analysis tools and database mining procedures, we refined the critical region to an interval of 200-kb and identified the interrupted ZPLD1 gene. We detected that the mRNA expression level of ZPLD1 gene is consistently decreased 2.5-fold versus control (P=0.0006) with allelic loss of gene expression suggesting that this protein may be part of the complex signaling pathway implicated in CCM formation.

Increased apoptosis, Huntingtin inclusions and altered differentiation in muscle cell cultures from Huntington's disease subjects.

Mutated huntingtin (htt) is ubiquitously expressed in tissues of Huntington's disease (HD) patients. In the brain, the mutated protein leads to neuronal cell dysfunction and death, associated with formation of htt-positive inclusions. Given increasing evidence of abnormalities in HD skeletal muscle, we extensively analyzed primary muscle cell cultures from seven HD subjects (including two unaffected mutation carriers). Myoblasts from presymptomatic and symptomatic HD subjects showed cellular abnormalities in vitro, namely mitochondrial depolarization, cytochrome c release, increased caspase-3, -8, and -9 activities, and defective cell differentiation. Another notable feature was the formation of htt inclusions in differentiated myotubes. This study helps to advance current knowledge about the downstream effects of the htt mutation in human tissues. Further applications may include drug screening using this human cellular model.

Cognitive Impairment in Relapsing-Remitting Multiple Sclerosis Patients with Very Mild Clinical Disability.

Cognitive dysfunction affects 40-65% of multiple sclerosis (MS) patients and can occur in the early stages of the disease. This study aimed to explore cognitive functions by means of the Italian version of the minimal assessment of cognitive function in MS (MACFIMS) in relapsing-remitting MS (RRMS) patients with very mild clinical disability to identify the primarily involved cognitive functions. Ninety-two consecutive RRMS patients with Expanded Disability Status Scale (EDSS) scores ≤ 2.5 and forty-two healthy controls (HC) were investigated. Our results show that 51.1% of MS patients have cognitive dysfunction compared to HC. An impairment of verbal and visual memory, working memory, and executive functions was found in the RRMS group. After subgrouping RRMS by EDSS, group 1 (EDSS ≤ 1.5) showed involvement of verbal memory and executive functions; moreover, group 2 (2 ≤ EDSS ≤ 2.5) patients were also impaired in information processing speed and visual memory. Our results show that utilizing a comprehensive neuropsychological assessment, approximately half of MS patients with very mild physical disability exhibit cognitive impairment with a primary involvement of prefrontal cognitive functions. Detecting impairment of executive functions at an early clinical stage of disease could be useful to promptly enroll MS patients in targeted rehabilitation.

Loss of normal huntingtin function: new developments in Huntington's disease research.

Huntington's disease is characterized by a loss of brain striatal neurons that occurs as a consequence of an expansion of a CAG repeat in the huntingtin protein. The resulting extended polyglutamine stretch confers a deleterious gain-of-function to the protein. Analysis of the mutant protein has attracted most of the research activity in the field, however re-examination of earlier data and new results on the beneficial functions of normal huntingtin indicate that loss of the normal protein function might actually equally contribute to the pathology. Thus, complete elucidation of the physiological role(s) of huntingtin and its mode of action are essential and could lead to new therapeutic approaches.

Family and molecular data for a fine analysis of age at onset in Huntington disease.

We analyzed the data on age at onset and CAG size of 319 patients clinically diagnosed with Huntington disease (HD) and 86 presymptomatic subjects recorded by four Italian Centers over the last 14 years. To overcome the problem of different CAG numbers found in each subject, also in the same family, the data were analyzed in terms of deviations from the average exponential relationship between onset and CAG number. The subject's year of birth was also considered to quantify possible sampling biases. Observations between relatives were compared with those of the whole group. The deviations were equal, on average, in subjects who inherited their HD gene from their fathers or mothers. Overall, our data argue in favor of a greater similarity across the same generation than across successive generations. In particular, an excess of parents with later than expected age of onset was observed, paralleled by a CAG-independent anticipation of onset in parent-child transmissions. These results can be interpreted in terms of a shared environment determining similar departures from the average CAG-onset relationship but also of a systematic effect that differentiates the two generations here examined.

Mutation of the PRNP gene at codon 211 in familial Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) belongs to a group of chronic, progressive, neurodegenerative disorders that may be hereditary, infectious, or sporadic. Hereditary CJDs are associated with mutations in the PRNP gene on chromosome 20p12-pter. We report a family in which four patients developed classical clinical signs of CJD, including severe cognitive decline, cerebellar signs, myoclonic jerks, and synchronic periodic discharges on electroencephalogram. The E211Q mutation has been identified in family members, but not in 97 sporadic CJD patients referred to the Italian registry of CJD nor in 205 healthy normal subjects, suggesting a pathogenic role for this mutation.

The prolonged cortical silent period in patients with Huntington's disease.

OBJECTIVES: In a group of patients with Huntington's disease and age-matched controls, we studied the cortical silent period (SP) elicited by single transcranial magnetic stimulation (TMS) pulses. METHODS: We measured the area of the pre-stimulus electromyographic (EMG) activity, the area of the motor evoked potentials (MEPs) and the duration of the SP induced by stimuli delivered at an intensity of 150% of motor threshold with a round coil placed over the vertex. We determined the cortical SP by sampling only the 5 traces containing the shortest SPs and by collecting 10 consecutive unselected traces without selecting trials. RESULTS: Patients and controls had normal EMG background areas, and MEP latencies and areas. Whereas data measured from selected trials gave a normal duration of the SP (patients, 154+/-58 ms; controls, 166+/-22 ms), data from unselected trials yielded a significantly longer SP duration in patients than in controls (356+/-251 vs. 159+/-44 ms) and also a larger variance and range. CONCLUSIONS: We conclude that in Huntington's disease, an abnormal cortical SP is best sought by collecting unselected consecutive traces. We suggest that the prolonged SP in HD originates from a dysfunction of the mechanisms controlling the restart of voluntary movement after TMS.

Onset and pre-onset studies to define the Huntington's disease natural history.

Huntington's disease's (HD) clinical history has not been defined yet. However, many aspects of the most confusing clinical stages, i.e., the first and last disease phases, including the symptom progression and the disease duration, have been better approached after discovery of the responsible gene. The existence of accurate genetic tests, available for affected and pre-symptomatic subjects (i.e., mutation carriers) and the possibility to study transgenic in vivo models, are actually helping us to understand some of the aspects of HD clinical presentation. HD may present with motor symptoms other than chorea, the psychiatric manifestations may represent part of the clinical picture and cognitive deterioration may occur very early in the disease and depend on early cortical involvement. Pre-onset studies are of crucial importance in understanding the temporal sequence of the clinical events. This is also very important for future therapeutic strategies in those diseases initiating late in the life, such as HD.

A double-blind cross-over trial of amantadine hydrochloride in Friedreich's ataxia.

We performed a double-blind cross-over study with amantadine hydrochloride in 12 patients with Friedreich's disease and 2 with autosomal dominant cerebellar ataxia. Patients were randomly assigned to a placebo-amantadine or amantadine-placebo sequence. The interval between the treatments was two weeks. Patients were graded according to a functional ataxia scoring scale and videotaped in basal conditions and 90 min after a single oral dose of 100 mg amantadine or placebo. Three evaluators independently scored the videotapes. Statistical analysis showed no significant effect of amantadine in Friedreich's disease.