Fragile X-associated tremor ataxia syndrome with co-occurrent progressive supranuclear palsy-like neuropathology.

Co-occurrence of multiple neuropathologic changes is a common phenomenon, most prominently seen in Alzheimer's disease (AD) and Parkinson's disease (PD), complicating clinical diagnosis and patient management. Reports of co-occurring pathological processes are emerging in the group of genetically defined repeat-associated non-AUG (RAN)-translation related diseases. Here we report a case of Fragile X-associated tremor-ataxia syndrome (FXTAS) with widespread and abundant nuclear inclusions of the RAN-translation related FMRpolyG-peptide. In addition, we describe prominent neuronal and glial tau pathology representing changes seen in progressive supranuclear palsy (PSP). The highest abundance of the respective pathological changes was seen in distinct brain regions indicating an incidental, rather than causal correlation.

Association of cognition with functional trajectories in patients admitted to geriatric wards: A retrospective observational study.

AIM: Impaired cognition is common among older patients admitted to acute hospitals, but its association with functional trajectories has not been well studied. METHODS: A retrospective observational study was carried out in an English tertiary university hospital. We analyzed all first episodes of county residents aged ≥75 years admitted to the Department of Medicine for the Elderly wards between December 2014 and May 2015. A history of dementia or a cognitive concern in the absence of a known diagnosis of dementia were recorded on admission. A cognitive concern included possible undiagnosed dementia or delirium. Function was retrospectively measured with the modified Rankin Scale at preadmission baseline, admission and discharge. RESULTS: There were 663 first hospital episodes over the period, of which 590 patients survived. Among the latter, 244 had no cognitive impairment, 134 a diagnosis of dementia, 66 a cognitive concern in the absence of a known dementia and 146 had missing cognitive data. When frailty, acuity, age and comorbidity were controlled for, people with known dementia had a similar functional recovery compared with those with no cognitive impairment. People with a cognitive concern, but no known dementia, had lesser functional recovery and greater disability at discharge than those with no cognitive impairment (mean discharge modified Rankin Scale 3.4 compared with 3.1, P = 0.011). CONCLUSIONS: Dementia per se might not be a marker of poor rehabilitation potential. Older people with acute cognitive concerns might be more vulnerable to poor functional recovery. Our cognitive variables are not gold standard, and further research is required to clarify this relationship. Geriatr Gerontol Int 2017; 17: 1438-1443.

Clinical frailty and functional trajectories in hospitalized older adults: A retrospective observational study.

AIM: Frailty predicts inpatient mortality and length of stay, but its link to functional trajectories is under-researched. Addenbrooke's Hospital, Cambridge, UK, collects the Clinical Frailty Scale (CFS) within 72 h of admission for those aged ≥75 years. We studied whether the CFS links to functional trajectories in hospitalized older adults. METHODS: This was a retrospective observational study in an English university hospital. We analyzed all first episodes of county residents aged ≥75 years admitted to the Department of Medicine for the Elderly wards between December 2014 and May 2015. Data were extracted from the hospital's information systems. Patients were classified as non-frail (CFS 1-4), moderately frail (CFS 5-6) and severely frail (CFS 7-8). Function was retrospectively measured with the modified Rankin Scale (mRS) at preadmission, admission and discharge. RESULTS: Of 539 eligible patients, 46 died during admission (mortality rates: 2% in CFS 1-4, 5% in CFS 5-6, 19% in CFS 7-8). Among the 493 survivors, 121 were non-frail, 235 moderately and 137 severely frail. The mean mRS of the non-frail was 1.8 (95% CI 1.7-2.0) at baseline, 3.3 (95% CI 3.1-3.5) on admission and 2.2 (95% CI 2.0-2.3) on discharge (mean length of stay 9 days). The moderately frail had a mean mRS of 2.9 (95% CI 2.8-3.0) at baseline, 4.0 (95% CI 3.8-4.1) on admission and 3.2 (95% CI 3.1-3.3) on discharge (mean length of stay 15 days). The severely frail had mean mRS of 3.5 (95% CI 3.3-3.6) at baseline, 4.3 (95% CI 4.1-4.4) on admission and 3.7 (95% CI 3.6-3.9) on discharge, respectively (mean length of stay 17 days). CONCLUSIONS: In older inpatients, frailty might be linked to lower and slower functional recovery. Prospective work is required to confirm these trajectories and understand how to influence them. Geriatr Gerontol Int 2017; 17: 1063-1068.

Unbiased screen reveals ubiquilin-1 and -2 highly associated with huntingtin inclusions.

Recently mutations in ubiquilin-2 were identified in patients with amyotrophic lateral sclerosis (ALS) and ALS/dementia providing direct evidence for the importance of this protein in neurodegenerative diseases. Histological studies have suggested that ubiquilin-1/-2 are associated with various pathological inclusions including Lewy bodies in Parkinson's disease, neurofibrillary tangles in Alzheimer's disease, polyQ inclusions in expansion repeat diseases and various proteinopathies associated with ALS and frontotemporal dementia. Using specific ubiquilin-2 antibodies and a series of transgenic mouse models of proteinopathies associated with neurodegenerative disease, we show that ubiquilin-2 preferentially associates with huntingtin polyQ expansion aggregates compared to α-synuclein, tau and several other types of protein inclusions. These results were confirmed by similar findings for ubiquilin-1 and -2 in human brain tissue sections, where accumulation was observed in huntingtin inclusions, but only infrequently in other types of protein inclusions. In cultured cells, ubiquilin-2 associates with huntingtin/polyQ aggregates, but this is not compromised by disease-causing mutations. Although ubiquilin proteins can function as chaperones to shuttle proteins for degradation, there is persistent co-localization between ubiquilin-2 and polyQ aggregated proteins during disease progression in the N586-82Q-C63 Huntington's disease mouse model. Thus, the co-localization of ubiquilin-2 with the huntingtin aggregates does not appear to facilitate aggregate removal.

Characterization of frontotemporal dementia and/or amyotrophic lateral sclerosis associated with the GGGGCC repeat expansion in C9ORF72.

Numerous kindreds with familial frontotemporal dementia and/or amyotrophic lateral sclerosis have been linked to chromosome 9, and an expansion of the GGGGCC hexanucleotide repeat in the non-coding region of chromosome 9 open reading frame 72 has recently been identified as the pathogenic mechanism. We describe the key characteristics in the probands and their affected relatives who have been evaluated at Mayo Clinic Rochester or Mayo Clinic Florida in whom the hexanucleotide repeat expansion were found. Forty-three probands and 10 of their affected relatives with DNA available (total 53 subjects) were shown to carry the hexanucleotide repeat expansion. Thirty-six (84%) of the 43 probands had a familial disorder, whereas seven (16%) appeared to be sporadic. Among examined subjects from the 43 families (n = 63), the age of onset ranged from 33 to 72 years (median 52 years) and survival ranged from 1 to 17 years, with the age of onset <40 years in six (10%) and >60 in 19 (30%). Clinical diagnoses among examined subjects included behavioural variant frontotemporal dementia with or without parkinsonism (n = 30), amyotrophic lateral sclerosis (n = 18), frontotemporal dementia/amyotrophic lateral sclerosis with or without parkinsonism (n = 12), and other various syndromes (n = 3). Parkinsonism was present in 35% of examined subjects, all of whom had behavioural variant frontotemporal dementia or frontotemporal dementia/amyotrophic lateral sclerosis as the dominant clinical phenotype. No subject with a diagnosis of primary progressive aphasia was identified with this mutation. Incomplete penetrance was suggested in two kindreds, and the youngest generation had significantly earlier age of onset (>10 years) compared with the next oldest generation in 11 kindreds. Neuropsychological testing showed a profile of slowed processing speed, complex attention/executive dysfunction, and impairment in rapid word retrieval. Neuroimaging studies showed bilateral frontal abnormalities most consistently, with more variable degrees of parietal with or without temporal changes; no case had strikingly focal or asymmetric findings. Neuropathological examination of 14 patients revealed a range of transactive response DNA binding protein molecular weight 43 pathology (10 type A and four type B), as well as ubiquitin-positive cerebellar granular neuron inclusions in all but one case. Motor neuron degeneration was detected in nine patients, including five patients without ante-mortem signs of motor neuron disease. While variability exists, most cases with this mutation have a characteristic spectrum of demographic, clinical, neuropsychological, neuroimaging and especially neuropathological findings.

Mutations in the colony stimulating factor 1 receptor (CSF1R) gene cause hereditary diffuse leukoencephalopathy with spheroids.

Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is an autosomal-dominant central nervous system white-matter disease with variable clinical presentations, including personality and behavioral changes, dementia, depression, parkinsonism, seizures and other phenotypes. We combined genome-wide linkage analysis with exome sequencing and identified 14 different mutations affecting the tyrosine kinase domain of the colony stimulating factor 1 receptor (encoded by CSF1R) in 14 families with HDLS. In one kindred, we confirmed the de novo occurrence of the mutation. Follow-up sequencing identified an additional CSF1R mutation in an individual diagnosed with corticobasal syndrome. In vitro, CSF-1 stimulation resulted in rapid autophosphorylation of selected tyrosine residues in the kinase domain of wild-type but not mutant CSF1R, suggesting that HDLS may result from partial loss of CSF1R function. As CSF1R is a crucial mediator of microglial proliferation and differentiation in the brain, our findings suggest an important role for microglial dysfunction in HDLS pathogenesis.

Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS.

Several families have been reported with autosomal-dominant frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), genetically linked to chromosome 9p21. Here, we report an expansion of a noncoding GGGGCC hexanucleotide repeat in the gene C9ORF72 that is strongly associated with disease in a large FTD/ALS kindred, previously reported to be conclusively linked to chromosome 9p. This same repeat expansion was identified in the majority of our families with a combined FTD/ALS phenotype and TDP-43-based pathology. Analysis of extended clinical series found the C9ORF72 repeat expansion to be the most common genetic abnormality in both familial FTD (11.7%) and familial ALS (23.5%). The repeat expansion leads to the loss of one alternatively spliced C9ORF72 transcript and to formation of nuclear RNA foci, suggesting multiple disease mechanisms. Our findings indicate that repeat expansion in C9ORF72 is a major cause of both FTD and ALS.

Ataxin-2 repeat-length variation and neurodegeneration.

Expanded glutamine repeats of the ataxin-2 (ATXN2) protein cause spinocerebellar ataxia type 2 (SCA2), a rare neurodegenerative disorder. More recent studies have suggested that expanded ATXN2 repeats are a genetic risk factor for amyotrophic lateral sclerosis (ALS) via an RNA-dependent interaction with TDP-43. Given the phenotypic diversity observed in SCA2 patients, we set out to determine the polymorphic nature of the ATXN2 repeat length across a spectrum of neurodegenerative disorders. In this study, we genotyped the ATXN2 repeat in 3919 neurodegenerative disease patients and 4877 healthy controls and performed logistic regression analysis to determine the association of repeat length with the risk of disease. We confirmed the presence of a significantly higher number of expanded ATXN2 repeat carriers in ALS patients compared with healthy controls (OR = 5.57; P= 0.001; repeat length >30 units). Furthermore, we observed significant association of expanded ATXN2 repeats with the development of progressive supranuclear palsy (OR = 5.83; P= 0.004; repeat length >30 units). Although expanded repeat carriers were also identified in frontotemporal lobar degeneration, Alzheimer's and Parkinson's disease patients, these were not significantly more frequent than in controls. Of note, our study identified a number of healthy control individuals who harbor expanded repeat alleles (31-33 units), which suggests caution should be taken when attributing specific disease phenotypes to these repeat lengths. In conclusion, our findings confirm the role of ATXN2 as an important risk factor for ALS and support the hypothesis that expanded ATXN2 repeats may predispose to other neurodegenerative diseases, including progressive supranuclear palsy.

Alzheimer disease-like phenotype associated with the c.154delA mutation in progranulin.

OBJECTIVE: To characterize a kindred with a familial neurodegenerative disorder associated with a mutation in progranulin (PGRN), with emphasis on the unique clinical features in this kindred. DESIGN: Antemortem and postmortem characterization of a kindred with a familial neurodegenerative disorder. SETTING: Multispecialty group academic medical center. PATIENTS: Affected members of a kindred with dementia with or without parkinsonism associated with a unique mutation in PGRN. MAIN OUTCOME MEASURE: Genotype-phenotype correlation. RESULTS: Of 10 affected individuals identified, 6 presented with early amnestic symptoms which resulted in initial diagnoses of Alzheimer disease or amnestic mild cognitive impairment. Some individuals presented with features characteristic of frontotemporal dementia. Mean age at onset was substantially younger in generation III (75.8 years; range, 69-80 years) than in generation II (60.7 years; range, 55-66 years). The pattern of cerebral atrophy varied widely in the affected individuals. Neuropathologic features in 6 individuals included frontotemporal lobar degeneration with ubiquitin-positive neuronal cytoplasmic and intranuclear inclusions (FTLD-U with NII). PGRN analysis revealed a single base pair deletion in exon 2 (c.154delA), which caused a frameshift (p.Thr52HisfsX2) and, therefore, creation of a premature termination codon and a likely null allele. CONCLUSIONS: In this large kindred, most affected individuals had clinical presentations that resembled Alzheimer disease or amnestic mild cognitive impairment associated with a mutation in PGRN and underlying FTLD-U with NII neuropathologic abnormalities. This finding is in distinct contrast to previously reported kindreds, in which clinical presentations have typically been within the spectrum of FTLD. The basis for the large difference in age at onset between generations requires further study.

Prominent phenotypic variability associated with mutations in Progranulin.

Mutations in progranulin (PGRN) are associated with frontotemporal dementia with or without parkinsonism. We describe the prominent phenotypic variability within and among eight kindreds evaluated at Mayo Clinic Rochester and/or Mayo Clinic Jacksonville in whom mutations in PGRN were found. All available clinical, genetic, neuroimaging and neuropathologic data was reviewed. Age of onset ranged from 49 to 88 years and disease duration ranged from 1 to 14 years. Clinical diagnoses included frontotemporal dementia (FTD), primary progressive aphasia, FTD with parkinsonism, parkinsonism, corticobasal syndrome, Alzheimer's disease, amnestic mild cognitive impairment, and others. One kindred exhibited maximal right cerebral hemispheric atrophy in all four affected individuals, while another had maximal left hemisphere involvement in all three of the affected. Neuropathologic examination of 13 subjects revealed frontotemporal lobar degeneration with ubiquitin-positive inclusions plus neuronal intranuclear inclusions in all cases. Age of onset, clinical phenotypes and MRI findings associated with most PGRN mutations varied significantly both within and among kindreds. Some kindreds with PGRN mutations exhibited lateralized topography of degeneration across all affected individuals.

Early onset familial Alzheimer Disease with spastic paraparesis, dysarthria, and seizures and N135S mutation in PSEN1.

OBJECTIVE: Early onset familial Alzheimer disease (EOFAD) can be caused by mutations in genes for amyloid precursor protein, presenilin 1 (PSEN1), or presenilin 2 (PSEN2). There is considerable phenotypic variability in EOFAD, including some patients with spastic paraparesis. The objective is to describe clinical and neuropathologic features of a family with a PSEN1 mutation that has been reported previously, without autopsy confirmation, in a single Greek family whose affected members presented with memory loss in their 30s, as well as variable limb spasticity and seizures. METHODS: We prospectively evaluated 2 children (son and daughter) with EOFAD and reviewed medical records on their mother. Archival material from the autopsy of the mother was reviewed and postmortem studies were performed on the brain of the daughter. RESULTS: All 3 individuals in this family had disease onset in their 30s, with cognitive deficits in multiple domains, including memory, language, and attention, as well as less common features such as spastic dysarthria, limb spasticity, and seizures. At autopsy both the mother and her daughter had pathologic findings of Alzheimer disease, and histologic evidence of corticospinal tract degeneration. Genetic studies revealed a mutation in PSEN1 leading to an asparagine to serine substitution at amino acid residue 135 (N135S) in presenilin 1. CONCLUSIONS: This is the first description of neuropathologic findings in EOFAD owing to N135S PSEN1 mutation. The clinical phenotype was remarkable for spastic dysarthria, limb spasticity, and seizures, in addition to more typical features of EOFAD.

Cholesterol-related genetic risk scores are associated with hypometabolism in Alzheimer's-affected brain regions.

We recently implicated a cluster of nine single nucleotide polymorphisms from seven cholesterol-related genes in the risk of Alzheimer's disease (AD) in a European cohort, and we proposed calculating an aggregate cholesterol-related genetic score (CREGS) to characterize a person's risk. In a separate study, we found that apolipoprotein E (APOE) epsilon4 gene dose, an established AD risk factor, was correlated with fluorodeoxyglucose (FDG) positron emission tomography (PET) measurements of hypometabolism in AD-affected brain regions in a cognitively normal American cohort, and we proposed using PET as a presymptomatic endophenotype to help assess putative modifiers of AD risk. Thus, the objective in the present study is to determine whether CREGS is related to PET measurements of hypometabolism in AD-affected brain regions. DNA and PET data from 141 cognitively normal late middle-aged APOE epsilon4 homozygotes, heterozygotes and noncarriers were analyzed to evaluate the relationship between CREGS and regional PET measurements. Cholesterol-related genetic risk scores were associated with hypometabolism in AD-affected brain regions, even when controlling for the effects of APOE epsilon4 gene dose. The results support the role of cholesterol-related genes in the predisposition to AD and support the value of neuroimaging in the presymptomatic assessment of putative modifiers of AD risk.

Phenotypic variability associated with progranulin haploinsufficiency in patients with the common 1477C-->T (Arg493X) mutation: an international initiative.

BACKGROUND: The progranulin gene (GRN) is mutated in 5-10% of patients with frontotemporal lobar degeneration (FTLD) and in about 20% of patients with familial FTLD. The most common mutation in GRN is Arg493X. We aimed to establish the contribution of this mutation to FTLD and related disorders. METHODS: We measured the frequency of Arg493X in 3405 unrelated patients with various neurodegenerative diseases using Taqman single-nucleotide polymorphism (SNP) genotyping. Clinicopathological characterisation and shared haplotype analysis were done for 30 families with FTLD who carry Arg493X. To investigate the effect of potential modifying loci, we did linear regression analyses with onset age as the covariate for GRN variants, for genotypes of the apolipoprotein E gene (APOE), and for haplotypes of the microtubule-associated protein tau gene (MAPT). FINDINGS: Of 731 patients with FTLD, 16 (2%) carried Arg493X. This mutation was not detected in 2674 patients who did not have FTLD. In 37 patients with Arg493X from 30 families with FTLD, clinical diagnoses included frontotemporal dementia, primary progressive aphasia, corticobasal syndrome, and Alzheimer's disease. Range of onset age was 44-69 years. In all patients who came to autopsy (n=13), the pathological diagnosis was FTLD with neuronal inclusions that contained TAR DNA-binding protein or ubiquitin, but not tau. Neurofibrillary tangle pathology in the form of Braak staging correlated with overall neuropathology in the Arg493X carriers. Haplotype analyses suggested that Arg493X arose twice, with a single founder for 27 families. Linear regression analyses suggested that patients with SNP rs9897528 on their wild-type GRN allele have delayed symptom onset. Onset ages were not associated with the MAPT H1 or H2 haplotypes or APOE genotypes, but early memory deficits were associated with the presence of an APOE epsilon4 allele. INTERPRETATION: Clinical heterogeneity is associated with GRN haploinsufficiency, and genetic variability on the wild-type GRN allele might have a role in the age-related disease penetrance of GRN mutations.

Voxel-based morphometry in frontotemporal lobar degeneration with ubiquitin-positive inclusions with and without progranulin mutations.

BACKGROUND: Mutations in the progranulin gene (PGRN) have recently been identified as a cause of frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) in some families. OBJECTIVE: To determine whether there is a difference in the patterns of atrophy in FTLD-U cases with and without PGRN mutations. DESIGN: Case-control study. SETTING: Brain bank of a tertiary care medical center. Patients Eight subjects who had screened positive for PGRN mutations (PGRN-positive) and who underwent volumetric magnetic resonance imaging were identified. Subjects were then matched by clinical diagnosis to a group of 8 subjects with a pathological diagnosis of FTLD-U who had screened negative for PGRN mutations (PGRN-negative). All subjects were then age-matched and sex-matched to a control subject. MAIN OUTCOME MEASURES: Voxel-based morphometry was used to assess the patterns of gray matter atrophy in the PGRN-positive group compared with the PGRN-negative group and compared with controls. RESULTS: The PGRN-positive group showed a widespread and severe pattern of gray matter loss predominantly affecting the frontal, temporal, and parietal lobes. The PGRN-negative group showed a less severe pattern of gray matter loss restricted mainly to the temporal and frontal lobes. On direct comparison, the PGRN-positive group showed greater gray matter loss in the frontal and parietal lobes compared with the PGRN-negative group. CONCLUSION: Findings from this study suggest that PGRN mutations may be associated with a specific and severe pattern of cerebral atrophy in subjects with FTLD-U.

Identification of a novel risk locus for progressive supranuclear palsy by a pooled genomewide scan of 500,288 single-nucleotide polymorphisms.

To date, only the H1 MAPT haplotype has been consistently associated with risk of developing the neurodegenerative disease progressive supranuclear palsy (PSP). We hypothesized that additional genetic loci may be involved in conferring risk of PSP that could be identified through a pooling-based genomewide association study of >500,000 SNPs. Candidate SNPs with large differences in allelic frequency were identified by ranking all SNPs by their probe-intensity difference between cohorts. The MAPT H1 haplotype was strongly detected by this methodology, as was a second major locus on chromosome 11p12-p11 that showed evidence of association at allelic (P<.001), genotypic (P<.001), and haplotypic (P<.001) levels and was narrowed to a single haplotype block containing the DNA damage-binding protein 2 (DDB2) and lysosomal acid phosphatase 2 (ACP2) genes. Since DNA damage and lysosomal dysfunction have been implicated in aging and neurodegenerative processes, both genes are viable candidates for conferring risk of disease.

Neuropathologic features of frontotemporal lobar degeneration with ubiquitin-positive inclusions with progranulin gene (PGRN) mutations.

Frontotemporal lobar degeneration is heterogeneous; cases with tau- and synuclein-negative, ubiquitin-positive neuronal inclusions are the most common, and some have mutations in the gene for progranulin (PGRN). The purpose of this study was to determine whether there were distinctive clinical and neuropathologic features of frontotemporal lobar degeneration with ubiquitin-positive inclusions with PGRN mutations. A retrospective review of medical records and semiquantitative neuropathologic analysis was performed on 18 PGRN(+) and 24 PGRN(-) cases. Clinically, PGRN(+) cases had more frequent language impairment and parkinsonism. Pathologically, PGRN(+) cases had smaller brains, more marked global atrophy, and more frontal atrophy. There was no difference in the frequency of hippocampal sclerosis. The pathology of PGRN(+) cases was relatively homogeneous, whereas PGRN(-) cases were more heterogenous. PGRN(+) cases had greater density of cortical ubiquitin-immunoreactive lesions, especially dystrophic neurites in layer II. Intranuclear inclusions were present in all PGRN(+) and 42% of PGRN(-) cases. The results suggest that frontotemporal lobar degeneration with ubiquitin-positive inclusions due to PGRN mutations has several characteristic features, including ubiquitin-immunoreactive neuritic pathology in superficial cortical layers and neuronal intranuclear inclusions. On the other hand, there is no histopathologic feature or combination of features that is pathognomonic. Neuronal intranuclear inclusions are virtually always present, but they can be detected in PGRN(-) cases.

Progranulin mutations in primary progressive aphasia: the PPA1 and PPA3 families.

BACKGROUND: Primary progressive aphasia (PPA) is a language-based dementia characterized by fluent or nonfluent language disorder as its principal feature. OBJECTIVE: To describe progranulin gene mutations in 2 families with PPA. DESIGN: Report of affected families. SETTING: Academic research. PATIENTS: Two families, PPA1 and PPA3, were studied. Genomic DNA was isolated from 3 of 4 siblings in PPA1, from all 3 siblings in PPA3, and from more than 200 control subjects. MAIN OUTCOME MEASURES: All 12 coding exons of the progranulin gene and the 5" and 3" untranslated regions were amplified by polymerase chain reaction and were sequenced in both directions using relevant primers. RESULTS: Both affected members of PPA1 for whom DNA was available and both affected sisters of PPA3 had a progranulin gene mutation not found in the unaffected siblings or in the controls. The mutations likely cause a null allele and a reduction in the level of functional progranulin protein. Both affected members of PPA1 with autopsies had frontotemporal lobar degeneration with tau-negative ubiquinated inclusions. CONCLUSIONS: To our knowledge, these are the only known families in which affected members display phenotypical homogeneity for PPA in the initial stages of the disease. In both families, the disease segregated with progranulin gene mutations. Whether progranulin dysfunction also extends to sporadic PPA and how it affects the initial anatomical specificity of neurodegeneration remain to be determined.

APOE is a potential modifier gene in an autosomal dominant form of frontotemporal dementia (IBMPFD).

PURPOSE: Inclusion-body myopathy, Paget's disease of bone and frontotemporal dementia is an adult-onset autosomal dominant illness (IBMPFD) caused by mutations in the valosin-containing protein (VCP) on chromosome 9p21.1-p12. The penetrance of the gene is 82% for myopathy, 49% for Paget's disease, but may be as low as 30% for frontotemporal dementia. Modifier genes could account for decreased frontotemporal dementia penetrance. In this study apolipoprotein-E (APOE) was evaluated for this role in IBMPFD families based on its known modifier effect in Alzheimer's disease. METHODS: From a database of 231 members of 15 families, 174 had APOE genotype available for analysis. Logistic regressions on APOE genotype and frontotemporal dementia were performed, using appropriate covariates. RESULTS AND CONCLUSION: FTD was associated with APOE 4 genotype (P=0.0002), myopathy (P=0.0006), and age (P=0.01), but not microtubule associated protein tau (MAPT) H2 haplotype (P=0.5) or gender (0.09) after adjustment for membership in pedigrees with at least one APOE 4 genotype. These data suggest a potential link between APOE 4 genotype and the specific form of frontotemporal dementia found in IBMPFD. The molecular basis of this link bears further investigation. We did not observe an association of frontotemporal dementia and H2 MAPT haplotype.

Lrrk2 G2019S substitution in frontotemporal lobar degeneration with ubiquitin-immunoreactive neuronal inclusions.

Leucine-rich repeat kinase 2 (LRRK2) mutation carriers can develop clinical symptoms other than typical parkinsonism such as dementia, amyotrophy or dystonia. To determine if LRRK2 mutations might be involved in frontotemporal dementia (FTD), 5 individuals with multiplex familial FTD kindreds and 41 pathologically confirmed cases of FTD, including 23 with a family history of dementia, were screened for genetic variations in the LRRK2 gene. We identified a LRRK2 mutation leading to the G2019S amino acid substitution in a 79-year-old woman with frontotemporal lobar degeneration with ubiquitinated neuronal intranuclear inclusions (FTLD-U/NII) and a possible family history of tremor. These findings may be coincidental; however, there is a small nucleus of LRRK2-positive patients displaying atypical features suggesting a role for this protein in other neurodegenerative disorders.

New genes, new dilemmas: FTLD genetics and its implications for families.

After Alzheimer's disease, frontotemporal lobar degeneration (FTLD) is the second leading cause of dementia in persons less than 65 years of age. Up to 40% of FTLD cases have a positive family history. Research on these families has led to the discovery of four disease-causing genes: microtubule-associated protein tau (MAPT), progranulin (PGRN), valosin-containing protein (VCP), and charged multivesicular body protein 2B (CHMP2B). MAPT and PGRN are responsible for the largest number of familial cases. Each of these genes differs by disease mechanism. Moreover mutations in both genes are associated with significant interfamilial and intrafamilial phenotypic variation. Genetic counseling needs to address the differences between the PGRN and MAPT mutations as well as the variation in clinical symptoms. The aims of this article are to describe the genetics of the FTLD spectrum and aid in the genetic counseling of individuals who may carry genetic mutations.