Stefania Cuccu

Bipolar affective disorder preceding frontotemporal dementia in a patient with C9ORF72 mutation: is there a genetic link between these two disorders?

The FTD includes three main clinical syndromes: the behavioural variant (bvFTD), semantic dementia and progressive non-fluent aphasia [1]. For the BvFTD, which is characterized by a rich constellation of psychiatric and behavioural symptoms, the differential diagnosis with psychiatric disorders like schizophrenia and affective disorders, may be challenging [2, 3]. Recently a hexanucleotide repeat expansion in a noncoding region of the C9ORF72 gene has been identified as the cause of chromosome 9p21-linked ALS, FTD and ALS–FTD [4, 5]. We report the case of a man who developed from the age of 42 years an affective disorder characterized by repeated manic and hypomanic episodes. The manic phases were characterized by euphoria, racing thoughts, logorrhea, very high self-esteem, artistic hyperproductivity, little need for sleep. The patient fulfilled the DSM IV criteria for bipolar affective disorder (BPAD) type I [6] and was put on a long term lithium therapy with a good clinical response; during manic phases haloperidol was administered up to the acute episode resolution. The patient worked as a teacher until the age of 57 years. A patient’s maternal uncle developed a parkinsonism at the age of 60. The patient aged 64 presented to our neurological unit because he developed euphoria, impulsivity, logorrhea, sexual disinhibition with his wife, delusional fixed ideas with repetitive behaviours. He was obsessed by the idea of cleaning or putting petrol in his car and spent all day watching sport TV shows. As many of these symptoms were present in the past BPAD episodes, the patient underwent a new psychiatric examination; low doses of haloperidol were started without any improvement, so the therapy was stopped. Later a progressive cognitive impairment appeared. Neuropsychological assessment showed marked attention and executive functions troubles, working memory impairment, anomia and verbal fluency dysfunction. Neurologic examination revealed mild parkinsonism with postural tremor, camptocormia, diffuse bradykinesia and rigidity. Extrapyramidal symptoms arose when the patient was not under antipsychotic treatment. Mutations of TARDBP and PGRN genes were excluded. The patient has been found positive for a GGGGCC hexanucleotide repeat expansion in the first intron of C9ORF72 gene ([70 repeats). Brain MRI showed bilateral frontotemporal atrophy, prominent in frontal areas (Fig. 1). The orbitofrontal cortex was more involved than the dorsolateral prefrontal cortex; moreover there was a significant involvement of the fronto-insula and anterior cingulate gyrus. Perfusion SPECT demonstrated reduction of uptake in the left frontotemporal and right frontoparietal regions (Fig. 1). Structural and functional neuroimaging findings G. Floris G. Borghero A. Cannas F. D. Stefano F. Marrosu Department of Neurology, Azienda Universitaria-Ospedaliera of Cagliari and University of Cagliari, Cagliari, Italy

Genetic loci linked to Type 1 Diabetes and Multiple Sclerosis families in Sardinia

BackgroundThe Mediterranean island of Sardinia has a strikingly high incidence of the autoimmune disorders Type 1 Diabetes (T1D) and Multiple Sclerosis (MS). Furthermore, the two diseases tend to be co-inherited in the same individuals and in the same families. These observations suggest that some unknown autoimmunity variant with relevant effect size could be fairly common in this founder population and could be detected using linkage analysis.MethodsTo search for T1D and MS loci as well as any that predispose to both diseases, we performed a whole genome linkage scan, sequentially genotyping 593 microsatellite marker loci in 954 individuals distributed in 175 Sardinian families. In total, 413 patients were studied; 285 with T1D, 116 with MS and 12 with both disorders. Model-free linkage analysis was performed on the genotyped samples using the Kong and Cox logarithm of odds (LOD) score statistic.ResultsIn T1D, aside from the HLA locus, we found four regions showing a lod-score ≥1; 1p31.1, 6q26, 10q21.2 and 22q11.22. In MS we found three regions showing a lod-score ≥1; 1q42.2, 18p11.21 and 20p12.3. In the combined T1D-MS scan for shared autoimmunity loci, four regions showed a LOD >1, including 6q26, 10q21.2, 20p12.3 and 22q11.22. When we typed more markers in these intervals we obtained suggestive evidence of linkage in the T1D scan at 10q21.2 (LOD = 2.1), in the MS scan at 1q42.2 (LOD = 2.5) and at 18p11.22 (LOD = 2.6). When all T1D and MS families were analysed jointly we obtained suggestive evidence in two regions: at 10q21.1 (LOD score = 2.3) and at 20p12.3 (LOD score = 2.5).ConclusionThis suggestive evidence of linkage with T1D, MS and both diseases indicates critical chromosome intervals to be followed up in downstream association studies.

Vitamin D Responsive Elements within the HLA-DRB1 Promoter Region in Sardinian Multiple Sclerosis Associated Alleles

Vitamin D response elements (VDREs) have been found in the promoter region of the MS-associated allele HLA-DRB1*15∶01, suggesting that with low vitamin D availability VDREs are incapable of inducing *15∶01 expression allowing in early life autoreactive T-cells to escape central thymic deletion. The Italian island of Sardinia exhibits a very high frequency of MS and high solar radiation exposure. We test the contribution of VDREs analysing the promoter region of the MS-associated DRB1 *04∶05, *03∶01, *13∶01 and *15∶01 and non-MS-associated *16∶01, *01, *11, *07∶01 alleles in a cohort of Sardinians (44 MS patients and 112 healthy subjects). Sequencing of the DRB1 promoter region revealed a homozygous canonical VDRE in all *15∶01, *16∶01, *11 and in 45/73 *03∶01 and in heterozygous state in 28/73 *03∶01 and all *01 alleles. A new mutated homozygous VDRE was found in all *13∶03, *04∶05 and *07∶01 alleles. Functionality of mutated and canonical VDREs was assessed for its potential to modulate levels of DRB1 gene expression using an in vitro transactivation assay after stimulation with active vitamin D metabolite. Vitamin D failed to increase promoter activity of the *04∶05 and *03∶01 alleles carrying the new mutated VDRE, while the *16∶01 and *03∶01 alleles carrying the canonical VDRE sequence showed significantly increased transcriptional activity. The ability of VDR to bind the mutant VDRE in the DRB1 promoter was evaluated by EMSA. Efficient binding of VDR to the VDRE sequence found in the *16∶01 and in the *15∶01 allele reduced electrophoretic mobility when either an anti-VDR or an anti-RXR monoclonal antibody was added. Conversely, the Sardinian mutated VDRE sample showed very low affinity for the RXR/VDR heterodimer. These data seem to exclude a role of VDREs in the promoter region of the DRB1 gene in susceptibility to MS carried by DRB1* alleles in Sardinian patients.

Genetic analysis for five LRRK2 mutations in a Sardinian parkinsonian population: Importance of G2019S and R1441C mutations in sporadic Parkinson’s disease patients

Mutations in the LRRK2 gene are the most common known cause of familial and sporadic Parkinsons disease (PD). Few studies performed to date to assess frequency of these mutations are actually only representative of specific areas. Here we study the frequency and clinical phenotype of LRRK2 G2019S, I2020T and R1441C/G/H mutations in 356 Sardinian patients with idiopathic PD and 208 controls. Seventeen additional subjects, relatives of PD mutated probands, were enrolled. Eight patients were mutated in heterozygosis for LRRK2 gene (2.3%): six carried the G2019S (1.7%) and two the R1441C (0.6%) mutation. Three PD patients G2019S carriers (50%) were detected in two contiguous villages comprising 3921 inhabitants while the other three (50%) were identified in the remaining population of 796,079 inhabitants. Only one mutated proband had a family history of PD. LRRK2 G2019S and R1441C mutations associated with PD were not an uncommon mutation in a Sardinian population, especially in sporadic PD patients. The detection of the G2019S variant in ten unaffected relatives confirms a reduced penetrance of the underlying mutation and might explain its prevalence among patients with sporadic PD. These findings may provide new insights into the importance of studies of frequency of LRKK2 mutations in PD patients originating from small ethnically homogeneous populations.

Parkin Exon Rearrangements and Sequence Variants in LRRK2 Mutations Carriers: Analysis on a Possible Modifier Effect on LRRK2 Penetrance

Mutations in LRRK2 represent the most common causes of Parkinsons disease (PD) identified to date, but their penetrance is incomplete and probably due to the presence of other genetic or environmental factors required for development of the disease. We analyzed the presence of parkin sequence variants (mutations or polymorphisms) and exon rearrangements in LRRK2 mutations carriers (both PD patients and unaffected relatives) in order to detect a possible modifier effect on penetrance. Eight families with nine PD patients with heterozygous LRRK2 mutations (identified within 380 Sardinian PD patients screened for the presence of the five most common LRRK2 mutations) and sixteen additional relatives were genetically investigated for the presence of LRRK2 and parkin mutations. No evidence was found for the presence of pathological parkin mutations or exon rearrangements in patients or not affected family members. Three single-nucleotide polymorphisms (SNPs) were identified both in patients and unaffected relatives but did not significantly differ between the two groups. These data provide no support to the hypothesis whereby such parkin gene mutations may be commonly implicated in possible effect on penetrance in LRRK2 mutation carriers.

Variation of the myelin oligodendrocyte glycoprotein gene is not primarily associated with multiple sclerosis in the Sardinian population

BackgroundMultiple sclerosis (MS) is consistently associated with particular HLA-DRB1-DQB1 haplotypes. However, existing evidence suggests that variation at these loci does not entirely explain association of the HLA region with the disease. The MOG locus is a prime positional and functional candidate for such additional predisposing effects but the analysis is complicated by the strong, albeit labyrinthine pattern of linkage disequilibrium in the region. Here we have assessed the association of MOG variation with MS in the Sardinian population to see if it represents an independent contributor to MS predisposition.ResultsAfter re-sequencing the MOG gene in 21 healthy parents of MS patients we detected 134 variants, 33 of which were novel. A set of 40 informative SNPs was then selected and assessed for disease association together with 1 intragenic microsatellite in an initial data set of 239 MS families. This microsatellite and 11 SNPs were found to be positively associated with MS, using the transmission disequilibrium test, and were followed up in an additional 158 families (total families analysed = 397). While in these 397 families, 8 markers showed significant association with MS, through conditional tests we determined that these MOG variants were not associated with MS independently of the main DRB1-DQB1 disease associations.ConclusionThese results indicate that variation within the MOG gene is not an important independent determinant of MS-inherited risk in the Sardinian population.

Constructional apraxia in frontotemporal dementia associated with the C9orf72 mutation: Broadening the clinical and neuropsychological phenotype

Abstract In our study we analysed clinical and neuropsychological data in a cohort of 57 Sardinian patients with FTD (55 apparently unrelated and two belonging to the same family), who underwent genetic screening for the C9orf72 mutation. Eight out of 56 patients were found positive for the C9orf72 mutation representing 14% of the entire cohort and 31.6% of the familial cases (6/19). C9orf72 mutated patients differed from the other FTD cases of the cohort for a younger age of onset, higher frequency of familial history for FTD and higher prevalence of delusional psychotic symptoms and hallucinations. In the neuropsychological assessment, C9orf72 mutated patients differed from non-mutated for the high frequency of visuospatial dysfunction regarding constructional apraxia (p = 0.02). In conclusion, our study confirms that Sardinian FTD patients have peculiar genetic characteristics and that C9orf72 mutated patients have a distinctive clinical and neuropsychological profile that could help differentiate them from other FTD patients. In our cohort we found that constructional apraxia, rarely reported in FTD, can properly discriminate between C9orf72 mutated and non-mutated patients and contribute to broaden the neuropsychological profile in frontotemporal dementia associated with this mutation.

C9ORF72 repeat expansion and bipolar disorder - is there a link? No mutation detected in a Sardinian cohort of patients with bipolar disorder

Recently (1), we described a patient with C9ORF72 repeat expansion (defined as more than 30 repeats) and a long history of bipolar disorder (BD) type I fulfilling the DSM-IV criteria (2), who developed behavioral frontotemporal dementia (bvFTD) at the age of 64 years. Age at onset of BD was 42 years. The patient responded well to long-term lithium therapy and low doses of haloperidol during the manic phases. Subsequently, we found another patient diagnosed with FTD who had received a diagnosis of BD at the age of 20 years and developed the first FTD symptoms when he was 51 years old. In both cases, there was no family history of BD; the first patient had a family history of Parkinson’s disease, and the second patient had a history of FTD. Meisler et al. (3) screened 89 patients with familial BD and found one two-generation family with BD with an expanded C9ORF72 repeat; in this family, the parent developed BD in the seventh decade and subsequently progressed to FTD, whereas the son was diagnosed with BD in the third decade of life. The authors concluded that C9ORF72 was not a major contributor to BD. Galimberti et al. (4) studied two cohorts of patients composed, respectively, of 206 German and 100 Italian patients with BD and found only one German patient carrying a C9ORF72 repeat expansion. The patient with the mutation was diagnosed with BD at the age of 37 years, had familiarity for Alzheimer’s disease, a negative family history for psychiatric disorders, and no signs of dementia at her last clinical interview at the age of 46 years. To further investigate the link between this repeat expansion and BD, we screened 206 Sardinian patients with BD for C9ORF72 repeat expansion with a technique that has been previously described (5). Sardinians have distinctive genetic characteristics compared with other Europeans and mainland Italians (6). The sample was comprised of 206 patients [65 male and 141 female; age at onset (mean standard deviation) = 26.75 10.75 years] diagnosed using DSM-IV criteria (2) and the Schedule for Affective Disorder and Schizophrenia–Lifetime Version (SADS-L) (7) who were recruited at the Lithium Clinic of the Clinical Psychopharmacology Centre of the University of Cagliari (Cagliari, Italy). Eighty patients had a family history of BD and the other 126 patients had sporadic BD. We did not find any patient with the mutation in our cohort. Taken together, these studies, conducted in different populations, suggest that C9ORF72 mutation is very rare in familial and sporadic BD (0–1%) while its frequency is significantly higher in patients with FTD or amyotrophic lateral sclerosis (8, 9). Considering the low number of patients identified by the different studies, it can be hypothesized that C9ORF72 mutations have a causative role only in rare cases of BD. It is possible that C9ORF72 mutations play a role both in neurodevelopment and in neurodegeneration, predisposing to BD in some cases and causing FTD in others (3). Meisler et al. (3) observed that C9ORF72 expansion may be associated with a form of BD that presents clinically with a classic phenomenology and progression to neurodegenerative disease. To our knowledge, only five patients with BD carrying a C9ORF72 mutation have been described in the literature (1, 3, 4). Three of these patients developed FTD after a long history of BD, while in the other two patients, the onset of FTD in later life cannot be ruled out, considering the young age of these subjects and the short period of follow-up. Therefore, an alternative hypothesis is that long-lasting BD preceding FTD represents a long prodromal phase of FTD that mimics the psychiatric disorder before the onset of

Phenotypic variability related to C9orf72 mutation in a large Sardinian kindred

Abstract We investigated intrafamilial phenotypic variability in carriers of the C9orf72 mutation, analysing clinical, neuropsychological and imaging characteristics of various members from a large Sardinian kindred with FTD or ALS. We compared these with those of C9 + patients in our ALS and FTD cohorts. Results showed that three patients carried the C9orf72 mutation: two with ALS and one with FTD and Parkinsonism. C9 + patients in our bvFTD Sardinian cohort had a higher frequency of Parkinsonism than non-mutated patients (75% vs. 36.3%, p <0.02). Parkinsonism was present in 2.7% of our ALS cohort and 3.3% of the C9 + patients. The prevalence of Parkinsonism in C9 + patients in the bvFTD and ALS cohorts showed a statistically significant difference (p <0.006). In conclusion, Parkinsonism was frequently associated with FTD but not ALS in a large Sardinian family, a finding reflected in the wider C9orf72 associated Sardinian ALS and FTD populations.

A genetic association study of two genes linked to neurodegeneration in a Sardinian multiple sclerosis population: The TARDBP Ala382Thr mutation and C9orf72 expansion

Multiple sclerosis (MS) is a chronic disease of the central nervous system characterized by inflammation and accompanied and followed by neurodegeneration. Missense mutations of the TAR DNA Binding Protein gene (TARDBP) located in the chromosome 1p36.22 region, and the hexanucleotide repeat expansions in chromosome 9 open reading frame 72 (C9orf72) are pathogenic in other neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Assuming that TARDBP Ala382Thr mutation and C9orf72 expansion may underlie MS, we evaluated their frequency in a large cohort of MS patients and controls from Sardinia, an island characterized by a very high frequency of MS and an unusual genetic background. Genomic DNA was extracted from peripheral blood and analyzed for the presence of a TARDBP Ala382Thr mutation and C9orf72 expansion. Difference in the frequency of these mutations between MS patients and controls was calculated using the χ(2) test with a standard 2×2 table. The Ala382Thr mutation in its heterozygous state was found in 27/1833 patients (1.4%) and 20/1475 controls (1.3%), whereas C9orf72 pathogenic repeat expansion was found in 6/1014 MS patients (0.6%) and 2/333 controls (0.6%). Individuals carrying the mutations did not present with other neurodegenerative conditions and any differences were reported between groups. TARDBP Ala382Thr mutation and C9orf72 expansion do not play a major role in MS pathogenesis in the Sardinian population. Further analyses on larger samples of MS patients from other populations are needed to better define the possible role of these genes in the complex interplay between neuroinflammation and neurodegeneration in MS.