Frontotemporal dementia (FTD) is the second most common cause of dementia in people under the age of 65 years. A large proportion of FTD patients (35-50%) have a family history of dementia, consistent with a strong genetic component to the disease. In 1998, mutations in the gene encoding the microtubule-associated protein tau (MAPT) were shown to cause familial FTD with parkinsonism linked to chromosome 17q21 (FTDP-17). The neuropathology of patients with defined MAPT mutations is characterized by cytoplasmic neurofibrillary inclusions composed of hyperphosphorylated tau. However, in multiple FTD families with significant evidence for linkage to the same region on chromosome 17q21 (D17S1787-D17S806), mutations in MAPT have not been found and the patients consistently lack tau-immunoreactive inclusion pathology. In contrast, these patients have ubiquitin (ub)-immunoreactive neuronal cytoplasmic inclusions and characteristic lentiform ub-immunoreactive neuronal intranuclear inclusions. Here we demonstrate that in these families, FTD is caused by mutations in progranulin (PGRN) that are likely to create null alleles. PGRN is located 1.7 Mb centromeric of MAPT on chromosome 17q21.31 and encodes a 68.5-kDa secreted growth factor involved in the regulation of multiple processes including development, wound repair and inflammation. PGRN has also been strongly linked to tumorigenesis. Moreover, PGRN expression is increased in activated microglia in many neurodegenerative diseases including Creutzfeldt-Jakob disease, motor neuron disease and Alzheimer's disease. Our results identify mutations in PGRN as a cause of neurodegenerative disease and indicate the importance of PGRN function for neuronal survival.

Frontotemporal dementia and amyotrophic lateral sclerosis are closely related clinical syndromes with overlapping molecular pathogenesis. Several families have been reported with members affected by frontotemporal dementia, amyotrophic lateral sclerosis or both, which show genetic linkage to a region on chromosome 9p21. Recently, two studies identified the FTD/ALS gene defect on chromosome 9p as an expanded GGGGCC hexanucleotide repeat in a non-coding region of the chromosome 9 open reading frame 72 gene (C9ORF72). In the present study, we provide detailed analysis of the clinical features and neuropathology for 16 unrelated families with frontotemporal dementia caused by the C9ORF72 mutation. All had an autosomal dominant pattern of inheritance. Eight families had a combination of frontotemporal dementia and amyotrophic lateral sclerosis while the other eight had a pure frontotemporal dementia phenotype. Clinical information was available for 30 affected members of the 16 families. There was wide variation in age of onset (mean = 54.3, range = 34-74 years) and disease duration (mean = 5.3, range = 1-16 years). Early diagnoses included behavioural variant frontotemporal dementia (n = 15), progressive non-fluent aphasia (n = 5), amyotrophic lateral sclerosis (n = 9) and progressive non-fluent aphasia-amyotrophic lateral sclerosis (n = 1). Heterogeneity in clinical presentation was also common within families. However, there was a tendency for the phenotypes to converge with disease progression; seven subjects had final clinical diagnoses of both frontotemporal dementia and amyotrophic lateral sclerosis and all of those with an initial progressive non-fluent aphasia diagnosis subsequently developed significant behavioural abnormalities. Twenty-one affected family members came to autopsy and all were found to have transactive response DNA binding protein with M(r) 43 kD (TDP-43) pathology in a wide neuroanatomical distribution. All had involvement of the extramotor neocortex and hippocampus (frontotemporal lobar degeneration-TDP) and all but one case (clinically pure frontotemporal dementia) had involvement of lower motor neurons, characteristic of amyotrophic lateral sclerosis. In addition, a consistent and relatively specific pathological finding was the presence of neuronal inclusions in the cerebellar cortex that were ubiquitin/p62-positive but TDP-43-negative. Our findings indicate that the C9ORF72 mutation is a major cause of familial frontotemporal dementia with TDP-43 pathology, that likely accounts for the majority of families with combined frontotemporal dementia/amyotrophic lateral sclerosis presentation, and further support the concept that frontotemporal dementia and amyotrophic lateral sclerosis represent a clinicopathological spectrum of disease with overlapping molecular pathogenesis.

The most common pathology in frontotemporal dementia (FTD) is tau-negative, ubiquitin-immunoreactive (ub-ir) neuronal inclusions (FTLD-U). Recently, we identified mutations in the progranulin (PGRN) gene as the cause of autosomal dominant FTLD-U linked to chromosome 17. Here, we describe the neuropathology in 13 patients from 6 different families, each with FTD caused by a different PGRN mutation. The most consistent feature was the presence of ub-ir lentiform neuronal intranuclear inclusions (NII) in the neocortex and striatum. In addition, the neocortex showed moderate-to-severe superficial laminar spongiosis, chronic degenerative changes, ub-ir neurites and well-defined ub-ir neuronal cytoplasmic inclusions (NCI). In the striatum, there were numerous ub-ir neurites. NCI in the hippocampus usually had a granular appearance. In contrast, familial FTLD-U cases without PGRN mutations had no NII, less severe neocortical and striatal pathology and hippocampal NCI that were more often solid. Eight cases in which genetic analysis was not available also had NII and an overall pathology similar to those with proven mutations. None of our cases of FTLD-U without NII showed the same pattern of pathology as those with mutations. These findings suggest that FTD caused by PGRN mutations has a recognizable pathology with the most characteristic feature being ub-ir NII.

Over 30 different mutations have now been identified in MAPt that cause frontotemporal dementia (FTD). However, there are several families with FTD that show definite linkage to the region on chromosome 17 that contains MAPt, in which no mutation(s) has been identified. Although these families could have a complex mutation of the MAPt locus that has evaded detection it is also possible that another gene in this region is associated with FTD. This possibility is supported by neuropathological findings in these families, which consist of neuronal inclusions that are immunoreactive for ubiquitin (ub-ir) but not for tau. In addition to neuronal cytoplasmic inclusions, several chromosome 17-linked families are reported to have ub-ir neuronal intranuclear inclusions (NII); a finding which is uncommon in sporadic FTD. Here, we describe detailed clinical and neuropathological findings in a new large, multigenerational family with autosomal dominant FTD and autopsy proven tau-negative, ub-ir neuronal cytoplasmic and intranuclear inclusions. We have demonstrated that this family is linked to a 19.06 cM region of chromosome 17q21 with a maximum multipoint LOD score of 3.911 containing MAPt. By combining the results of our genetic analysis with those previously published for other families with similar pathology, we have further refined the minimal region to a 3.53 cM region of chromosome 17q21. We did not identify point mutations in MAPt by direct sequencing or any gross MAPt gene alterations using fluorescent in situ hybridization. In addition, tau protein extracted from members of this family was unremarkable in size and quantity as assessed by western blotting. Neuropathological characterization of the ub-ir NII in this family shows that they are positive for promyelocytic leukaemia protein (PML) and SUMO-1 that suggests that these inclusions form in the nuclear body and suggests a possible mechanism of neurodegeneration in tau-negative FTD linked to chromosome 17q21.

This study indicates that an MS diagnosis does not completely deter the consideration of childbearing in MS patients of both genders.

Objectives:In 2007, a novel pathogenic genetic mutation associated with early onset familial Alzheimer disease was identified in a large First Nation family living in communities across British Columbia, Canada. Building on a community-based participatory study with members of the Nation, we sought to explore the impact and interplay of medicalization with the Nation’s knowledge and approaches to wellness in relation to early onset familial Alzheimer disease.Methods:We performed a secondary content analysis of focus group discussions and interviews with 48 members of the Nation between 2012 and 2013. The analysis focused specifically on geneticization, medicalization, and traditional knowledge of early onset familial Alzheimer disease, as these themes were prominent in the primary analysis.Results:We found that while biomedical explanations of disease permeate the knowledge and understanding of early onset familial Alzheimer disease, traditional concepts about wellness are upheld simultaneously.Conclusion:The analysis brings the theoretical framework of “two-eyed seeing” to the case of early onset familial Alzheimer disease for which the contributions of different ways of knowing are embraced, and in which traditional and western ways complement each other on the path of maintaining wellness in the face of progressive neurologic disease.

A novel, pathogenic presenilin 1 (PS1) mutation has recently been identified in a large Aboriginal kindred living in dispersed communities throughout British Columbia, Canada. Disseminating genetic information and ensuring that appropriate genetic counseling services are provided to all concerned relatives have posed several unique challenges. These challenges include knowledge exchange and continuity of care in a geographically remote and culturally distinct community. To our knowledge, this is the first time a specific genetic counseling approach has been needed for early-onset familial Alzheimer disease (EOFAD) in a North American Aboriginal community.

The meaningful consideration of cultural practices, values and beliefs is a necessary component in the effective translation of advancements in neuroscience to clinical practice and public discourse. Society’s immense investment in biomedical science and technology, in conjunction with an increasingly diverse socio-cultural landscape, necessitates the study of how potential discoveries in neurodegenerative diseases such as Alzheimer disease are perceived and utilized across cultures. Building on the work of neuroscientists, ethicists and philosophers, we argue that the growing field of neuroethics provides a pragmatic and constructive pathway to guide advancements in neuroscience in a manner that is culturally nuanced and relevant. Here we review a case study of one issue in culturally oriented neuroscience research where it is evident that traditional research ethics must be broadened and the values and needs of diverse populations considered for meaningful and relevant research practices. A global approach to neuroethics has the potential to furnish critical engagement with cultural considerations of advancements in neuroscience.