Epidemiological surveillance of amyotrophic lateral sclerosis and parkinsonism-dementia in the Commonwealth of the Northern Mariana Islands

Amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia (PD), two fatal neurological diseases of unknown cause, occur in high incidence among the Chamorro people of Guam, the largest and southernmost island within the Mariana archipelago. To reassess and extend our present epidemiological knowledge of these degenerative diseases in this focal geographical region, a systematic search for both disorders was conducted on the remaining inhabited islands of Rota, Tinian, Saipan, and the four remote islands of Anatahan, Alamagan, Pagan, and Agrihan within the Marianas chain. One case of ALS (on Saipan), 2 cases of PD (on Rota and Saipan), and 6 cases of parkinsonism without dementia (2 on Rota, 3 on Saipan, 1 on Tinian) were encountered among the approximately 17,000 inhabitants. No cases of either ALS, PD, or parkinsonism were found in the four remote Northern Islands. An additional 22 cases of ALS and 8 cases of PD were identified from reports of previous case-finding surveys, hospital records, and death certificates. Among Chamorros born on Rota, the average annual age-adjusted mortality rates of ALS per 100,000 population were 37.7 for the 15-year period 1956 to 1970 and 22.5 for the past decade, 1971 to 1980. Among Chamorros born on Saipan, the average annual mortality rates were 7.2 and 3.2 per 100,000, respectively, for the two periods. The mortality rates of PD were also significantly lower on Saipan than on Rota. In general, the age-adjusted mortality rates of ALS and PD on Rota were similar to those currently observed on Guam. Since the origins and current genotypic composition of Chamorros on all the Mariana Islands are indistinguishable, the strikingly lower mortality rates of ALS and PD on Saipan suggest that environmental factors are far more important than genetic factors in the pathogenesis of these diseases.     

ALS incidence in Nova Scotia over a 20-year-period: a prospective study

OBJECTIVE: Previous studies have suggested that the incidence of amyotrophic lateral sclerosis (ALS) in Nova Scotia is relatively high and increasing over time. This study was performed to determine the current incidence of ALS in Nova Scotia and to compare this to data collected in 1984 and 1995. METHODS: All physiatrists and neurologists were surveyed on a monthly basis over one year to record all new cases of ALS diagnosed in Nova Scotia. Data was compared to that collected using similar methods in 1984 and 1995. To validate our methods, we also performed a retrospective study using a provincial health care database. RESULTS: There were 21 new ALS cases in Nova Scotia during the 2003 study period, yielding a crude incidence of 2.24/100,000. The age-adjusted incident rate for 2003 was 2.13 (95% CI = 0.11-4.15). The age-adjusted rate for 1995 was 2.3 (95% CI = 0.08-4.53) while the age-adjusted rate for 1984 was 2.22 (95% CI = 0.13-4.32). Analysis of provincial health records identified 24 cases of ALS and an age-adjusted incidence of 2.44/100,000. CONCLUSIONS: The age-adjusted incidence of ALS in Nova Scotia has remained stable over the period 1984-2003. The incidence is similar to that reported in several other parts of the world.     

Muro disease or ALS-parkinsonism-dementia complex of the Kii peninsula of Japan]

"Muro disease" is an endemic ALS in the Muro district that includes the southern coastal mountainous areas of the Kii peninsula of Japan. Epidemiological survey in 1960s disclosed extremely high incidence of ALS in two villages, Hohara and Kozagawa, and disappearance of high incidence by early 1980s was reported with its etiology unsolved. We resurveyed for neurodegenerative diseases in Hohara and found continuous high ALS incidence. We also found parkinsonism-dementia complex (PDC) verified neuropathologically. ALS and PDC frequently occurred in one individual simultaneously and affected many members in the same family, and neuropathological findings of ALS and PDC were similar to each other, showing a combination of upper and lower motor neuron involvements and many neurofibrillar tangles (NFTs) in the brainstem and cerebral cortex, resembling those of ALS/PDC on Guam. TDP-43 positive inclusions were found in the dentate gyrus of the hippocampus and spinal motor neurons in all cases examined. Age-adjusted incidence rates during 1950 and 2000 have showed that incidence of ALS was gradually declining for 50 years while that of PDC rose up steeply in 1990s. No particular environmental factors were confirmed and gene analyses of candidate genes of ALS, parkinsonism and dementia failed to reveal any mutations. Continuing high incidence and high rates of familial occurrence suggest that primary cause of Kii ALS/PDC may be genetic rather than environmental.     

ALS-parkinsonism-dementia complex of Kii and other related diseases in Japan

The ALS/parkinsonism-dementia complex (PDC) of Kii is an endemic disease with a diverse phenotypic expression characteristic of classical ALS, parkinsonism and dementia. Its clinical and neuropathological manifestations are similar to a syndrome found in Guam, sharing classical ALS pathology together with many neurofibrillary tangles in the brain. The incidence rates of ALS declined dramatically between the 1950s and 1980s. In the 1990 s, Kuzuhara found a high incidence of PDC with abundant neurofibrillary tangles, similar to Guamanian PDC. The incidence rates of PDC dramatically rose during the 1980s and 1990 s, and PDC replaced ALS. More than 70% of patients in the endemic region had a family history of ALS or PDC. We recently found a new gene OPTN causing ALS, and have extended its clinical survey in Japan. Two autopsied cases showed involvement of basal ganglia and/or cerebral cortex with neurofibrillary tangles. A few family members also showed dementia and parkinsonism without evidence of motor neuron disease. Moreover the penetrance seems to be incomplete. Despite these similarities, OPTN mutations were not found in the Kii patients. We speculate that the Kii/ALS-PDC could primarily be a genetic disease, and its clinical manifestation is modified by other genes or environmental factors.     

The nature of the parkinsonism-dementia complex and amyotrophic lateral sclerosis of Guam and magnesium deficiency

The parkinsonism-dementia complex (PDC) and amyotrophic lateral sclerosis (ALS) were the fatal neurological diseases, showing very high incidence during 1950-1970 and dramatic decrease after 1970 on Guam. Through the research, the present author insisted that; (1) NFTs in Guam ALS patients are merely a background feature widely dispersed in the population, (2) Guam ALS and PDC are basically different diseases, and (3) Guam ALS occurs initially as classic ALS. As pathogeneses of the diseases, intake of low calcium (Ca) and magnesium (Mg) and high aluminum water and of some plant excitatory neurotoxin has been speculated. To elucidate the pathogenesis, the author performed an experiment exposing rats to low Ca and/or Mg intake for two generations, so as to follow the actual way of human living on the island, since several generations live continuously in the same environment. The study indicates that continuous low Mg intake for two generations induces exclusive loss of dopaminergic neurons in in rats, and may support the Mg hypothesis in the pathogenesis of PDC of Guam.     

Hippocampal and entorhinal cortex neurofibrillary tangle formation in Guamanian Chamorros free of overt neurologic dysfunction

Since first described, amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of Guam has represented an important model of age-related neurodegenerative disease. ALS/PDC is characterized neuropathologically by severe widespread involvement by neurofibrillary tangles (NFTs). Over the past 30 years there has been a dramatic decrease in the incidence of ALS and a 10-year increase in the age of onset of ALS and PDC. In 1979, Anderson et al reported evidence of significant NFT involvement in Guam natives who had been free of evidence of neurologic dysfunction. Using the slides from this study, we re-examined the extent of hippocampus and entorhinal NFT involvement and compared it to brains recently obtained from neurologically intact Guam natives and age-matched controls from New York. The tendency towards hippocampal and entorhinal NFT formation continues to be encountered among the inhabitants of Guam, particularly among those over age 50. although severe involvement was less commonly noted in relatively young individuals (< 50 years). As noted by Anderson et al, the pattern of neuropathologic lesions seen in those with extensive NFT involvement suggests that such cases represent preclinical examples of ALS/PDC in individuals who have yet to accumulate a sufficient burden of pathology to attract clinical attention and diagnostic evaluation.     

Temporal trend of amyotrophic lateral sclerosis incidence in southern Europe: a population study in the health district of Ferrara, Italy

Data about the temporal trend of amyotrophic lateral sclerosis (ALS) incidence in southern Europe are scarce. Incidence studies on ALS have been carried out in the health district of Ferrara, Italy, since 1960s. We expanded the previous studies from 1964 to 2009. The study was prospective with a subsequent retrospective intensive survey of multiple sources of case ascertainment. All patients with a definite and probable ALS according to the original El Escorial criteria were selected. There were 130 incident cases in the years 1964-2009 giving an average annual crude incidence of 1.82 per 100,000 population (95% CI 1.53-2.17). An incidence increase during the study period was estimated in women (χ(2) test for trend = 7.19, p < 0.01) and in the elderly (χ(2) test for trend = 7.803, p < 0.01). The age-adjusted incidence was stable over time in both women (1.19 per 100,000, 95% CI 0.90-1.52) and men (1.45 per 100,000, 95% CI 0.12-1.84). The annual number of new ALS cases in the study population followed the Poisson distribution in both sexes as well as in the elderly group of the population. The present findings suggest that ALS incidence is nearly stable over time. The crude incidence increase we estimated over time among women is mainly explained by population ageing. The increasing incidence in the elderly population was likely the consequence of an increasing precision in ALS diagnosis in the elderly since the increasing attention and care over time of neurologic elderly patients that likely concern elderly women more than previous time periods rather than better case ascertainment of diagnosed patients. The present findings do not support the role of specific environmental factors in ALS pathogenesis.     

Lessons from Guam ALS/PDC study]

An extraordinarily high incidence of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) affecting the native population was discovered on the island of Guam a half century ago. Guam ALS is identical to classic ALS clinically and pathologically while PDC is marked by progressive parkinsonism and dementia. The unusual histological finding in these fetal neurodegenerative diseases is the presence of numerous neurofibrillary tangles in a selective topographic distribution unassociated with senile plaques. There have been remarkable advances in field of age-associated neurodegenerative disease after our initial study of Guam cases. Four noteworthy topics are presented in this communication. 1) Clinically, the coexistence of parkinsonism and dementia was frequently recognized in Parkinson disease and Alzheimer disease. Some other new disease entities characterized by coexistence of parkinsonism and dementia have been reported. These include progressive supranuclear palsy, frontotemporal dementia and parkinsonism linked to chromosome 17. 2) Neuropathologically, abundant neurofibrillary tangles unassociated with senile plaques were demonstrated in many diseases such as aftermath of boxing and tangle-only dementia. Furthermore, tau-positive structures were recognized not only in neurons but in glial cells in certain diseases. Tauopathy is one of the current hot research subjects. 3) Familial aggregation of Guam ALS patients provoked investigation of familial ALS elsewhere. Familial motor neuron disease with SOD1 mutation is the target of worldwide intense investigation at the present time. SOD1 gene mutation is, however, not found in Guam ALS. 4) The most striking findings of the Guam study is the gradual decline in the incidence of ALS on Guam during a quarter century and virtual disappearance of new patients. This may be linked to a remarkable change in environment and life style of the Chamorro population. The etiology of ALS is still unknown and no new treatment is available. Guam ALS/PDC is certainly one of the most mysterious riddles among age-associated neurodegenerative diseases during the last half a century.     

Changes in the incidence of amyotrophic lateral sclerosis in Israel

The incidence of amyotrophic lateral sclerosis (ALS) in Israel was determined for the period 1959 through 1974. A total of 246 patients with ALS was ascertained. The male-female ratio was 1.62:1. The average annual age-adjusted incidence per 100,000 persons increased during this period by 41%. The increase was almost entirely due to a higher rate in persons more than 60 years of age and was greater in women than in men. This led to a decrease in the male-female ratio. The mean age of onset increased from 52.8 to 58.6 years during the same period. The increment in incidence could not be explained by better case ascertainment or increased life expectancy, but greater precision in diagnosis of ALS in the aged may have partially contributed to the increase.     

Amyotrophic lateral sclerosis of Guam: the nature of the neuropathological findings

To elucidate the fundamental differences and similarities of the neuropathological features and etiopathogenesis of the amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) of Guam, we conducted a topographic, quantitative and histological investigation of tau-containing neurons, neurofibrillary tangles (NFTs), Bunina bodies and ubiquitinated inclusion bodies in 27 non-ALS non-PDC Guamanian subjects, as well as 10 Guam ALS patients, 28 PDC patients, and 5 patients with combined ALS and PDC (ALS-PDC). The topographic distribution of NFTs was basically the same in each disease and also in the non-ALS non-PDC group. There were relatively few, if any, NFTs in non-ALS non-PDC subjects and ALS patients, but there were many, especially in the frontal and temporal cortex, in Guam PDC and ALS-PDC patients. The histological and ultrastructural features of Bunina bodies in Guam ALS and ALS-PDC patients were similar to those reported in classic ALS. The ratio of occurrence of the inclusion in Guam ALS and ALS-PDC patients was similar to that reported so far in classic ALS. Ubiquitinated skein-like inclusion bodies were observed in the spinal anterior horn cells in Guam ALS and ALS-PDC patients. These findings indicate that classic ALS does exist on Guam, that NFTs in Guam ALS patients are merely a background feature widely dispersed in the population, that the mechanism of neuronal degeneration of Guam ALS is basically different from that of PDC, and that Guam ALS occurs initially as classic ALS.Supported in part by a Grant-in-Aid for Scientific Research (c) 05680653 from the Ministry of Education, Science and Culture and a research grant for CNS degenerative diseases from the Ministry of Health and Welfare, JapanMedical student of Leiden University, Holland, in 1981. He stayed on Guam and accomplished his thesis on part of this study under the guidance of Drs. K.-M. Chen and K. Oyanagi.     

Clinical features and changing patterns of neurodegenerative disorders on Guam, 1997-2000.

BACKGROUND: In the 1950s, high-incidence ALS and Parkinson-dementia complex (PDC) were identified among Chamorros, the native inhabitants of Guam. Brains of patients with these syndromes showed widespread neurofibrillary tangles. Although ALS and PDC were reported to have dramatically declined in the 1980s, new cases are still encountered. Late-life dementia has received little study among Chamorros. METHODS: From 1997 to 2000, the authors evaluated newly referred and previously identified patients. They screened first-degree relatives of previous registries, and subjects aged 60 or older. Subjects who scored below a cognitive test cutoff or had symptoms or signs consistent with parkinsonism or ALS underwent psychometric testing, assessment by a neurologist, and laboratory studies as appropriate. Consensus diagnoses were made. RESULTS: The authors identified 194 Chamorros with ALS (n = 10), PD (n = 11), PDC (n = 90), or late-life dementia (n = 83). Mean ages at onset were 55 for ALS, 68 for PDC, 63 for PD, and 74 for dementia. Late-life dementia was more common in women, and met criteria for probable or possible AD. The APOE-epsilon 4 allele frequency was uniformly low regardless of neurologic diagnosis. CONCLUSIONS: The rapid decline of high-incidence ALS on Guam over the past 40 years suggests the contribution of a modifiable environmental factor. PDC remains relatively common, with an unchanged clinical picture apart from later age at onset. Dementia among elderly Chamorros (termed "Mariana dementia") resembles AD. Autopsy studies will clarify whether this dementia is related to AD pathology or represents a late-life neurofibrillary tangle syndrome more closely allied to PDC.     

Neuroepidemiologic research initiatives on Guam: past and present.

Since the middle of this century, a remarkable concentration of cases of neurodegenerative disease(s), referred to as amyotrophic lateral sclerosis and Parkinson-dementia complex (ALS/PDC), has been recognized among Chamorro natives of Guam. Intense investigations over the last 4 decades have failed to determine the etiology of these invariably fatal diseases. Over the same time period, the incidence of ALS has decreased dramatically, the incidence of PDC has decreased, but to a lesser degree, and age at onset has shifted to a later age by about 1 decade. Almost 50% of demented patients present without the classical Parkinsonian features of PDC, and the morphological picture has changed. Results of past and present research initiatives are reviewed.     

Amyotrophic lateral sclerosis-parkinsonism-dementia complex of the Kii Peninsula of Japan]

The Hohara village of the Kii peninsula is one of the high incidence ALS foci, and the high incidence was reported to have ended in early 1980s. However, we have found the ALS incidence rate has been still high, more than 100 times of the other areas of Japan. In addition, we have found many cases of parkinsonism-dementia complex (PDC). ALS and PDC often occur simultaneously in a single patient or in a single family. Family history was positive in more than 70% of patients. ALS and PDC showed common neuropathological findings consisting of ALS pathology and many neurofibrillary tangles (NFT) without senile plagues, and isoform pattern of NFT tau protein was similar to that of Alzheimer disease (AD), but different from that of progressive supranuclear palsy (PSP) or Pick's disease (PiD). Kii ALS/PDC may be a novel tauopathy that differ from AD, PSP or PiD.     

Neuropathology of parkinsonism-dementia complex and amyotrophic lateral sclerosis of Guam: an update

A comparative study was performed to investigate the differences and similarities of the neuropathological findings in the parkinsonism-dementia complex (PDC) and amyotrophic lateral sclerosis (ALS) of Guam, progressive supranuclear palsy and classic ALS. Based on the findings, it is proposed that (a) PDC is a discrete disease entity, (b) NFTs in Chamorro ALS are merely a background feature widely distributed in this population, (c) Chamorro ALS is a disease combined with classic ALS and neurofibrillary degeneration, (d) thus a subtype of “Guam ALS” is not present, and (e) PDC and ALS of Guam are different diseases.

     

Amyotrophic lateral sclerosis a population study

Summary A country-wide study of the frequency of amyotrophic lateral sclerosis (ALS) was undertaken in Israel for the period 1960–1970. Israel was chosen for this study because of its excellent medical facilities and detailed demographic information. Moreover, the population includes representative groups from all parts of the world for comparison of frequency. A wide variety of motor system disease was screened in all hospitals, clinics, and chronic care facilities in the country, death certificates were reviewed and physicians with a neurological practice were contacted to derive a tentative list of cases. Only those who fit strict clinical diagnostic criteria or had autopsy confirmation were included in estimates of prevalence and incidence.On January 1, 1965, the mid-point of the study, 62 patients with ALS were living in Israel. The age-adjusted prevalence of ALS on that date was 3 per 100000 population. The average annual age-adjusted incidence for the period 1960–1970 was 0.78 per 100000 population (0.86 in males, 0.46 in females; ratio 1.9:1). There was no appreciable change in trend of incidence over the study interval. Age-specific incidence rates were similar in native-born inhabitants of Israel, immigrants from Europe and immigrants from Afro-Asian countries. The range in age-adjusted incidence among subgroups of immigrants to Israel from various countries was 0.25 to 1.20 per 100000 population but small numbers precluded testing the statistical significance of these rather narrow differences.Mean age at onset was 55.4 years for males and 52.4 years for females. The mean age at death was 60.2 for males and 58.0 for females. The average annual mortality from ALS was 0.58 per 100000 population. There were no familial aggregates of ALS in Israel and autopsy data showed no neurofibrillary changes, granulovacuolar or inclusion bodies.There are only a few other population studies of ALS in different regions of the world. The average annual incidence in these other studies ranged from 0.4 to 1.4 per 100000 population. Thus, the incidence in Israel falls within this narrow range. The present study lends further support to the impression that ALS has a remarkably uniform geographic distribution with Guam and the Kii peninsula of Japan being the only known areas with significantly high rates. If an environmental factor contributes to the pathogenesis of ALS, the factor must also have a uniform geographic distribution.Supported in part by the Minneapolis Veterans Administration Hospital.     

ALS and PDC of Guam: forty-year follow-up

BACKGROUND: It was noticed in the mid-1950s that the incidence of ALS and parkinsonism--dementia complex (PDC) were much higher on Guam than anywhere else in the world. In 1958, a registry of patients and controls was established to ascertain the familial and genetic aspects of these diseases. Patients and individually matched controls and their relatives were registered from 1958 to 1963. The registry was updated and analyzed in 1998 through 1999. OBJECTIVE: To ascertain whether first-degree relatives of patients had a higher risk for developing ALS or PDC than relatives of controls. Methods: During the period of 1958 to 1963, 126 new patients and 126 individually matched controls and their respective first-degree relatives and spouses were evaluated neurologically and registered. Forty years later, the number of new cases among the patient and control relatives were compared to an expected number of new cases based on the age- and sex-specific incidence of ALS and PDC in the population at large. RESULTS: From 1958 to 1999, there were 102 new ALS or PDC cases among relatives of patients and 33 among relatives of controls. These values were compared with the derived expected values. There were more observed than expected new cases among patients' relatives, and less observed cases than expected among the controls' relatives. CONCLUSIONS: Relatives of patients with ALS or PDC have significantly higher risks for developing the disease than the Guamanian population, whereas relatives of controls have significantly lower risks.     

The ALS/PDC syndrome of Guam and the cycad hypothesis

There is a high incidence on Guam of a severe tauopathy known as the Parkinson- dementia complex (PDC). It is linked with an even more malignant amyotrophic lateral sclerosis (ALS) syndrome. There is great interest in determining the cause, or causes, of the Guam ALS/PDC syndrome because insight might be gained regarding ALS and the more common tauopathies found throughout the world. Research into the disorder is stimulated by hypotheses as to cause. Such hypotheses should be compatible with the known epidemiology and pathology of the syndrome. These include a high, if not exclusive, restriction to the Chamorro population, familial occurrence, a regional variation on Guam itself, a definite persistence but with declining incidence, and a possible duplication in isolated villages on the Kii peninsula of Japan. Proposed causation factors should also be able to reproduce the syndrome in experimental systems. This includes induction of neurofibrillary tangles with a tau isoform distribution similar to that of Alzheimer disease and association of the lesions with TDP-43 and Lrrk2. A recurring hypothesis as to causation is exposure to Cycas micronesica, the false Sago palm known locally as fadang. We review the reasons why this hypothesis falls short of the minimal criteria needed for further serious consideration and discuss some other possibilities that should not be excluded.     

Clinical aspects, imaging and neuropathology of Kii ALS/PDC]

During 1996 and 2006, we examined clinically 37 patients and neuropathologically 13 autopsy cases with amyotrophic lateral sclerosis/parkinsonism-dementia complex of the Kii peninsula (Kii ALS/PDC). The ages of onset were between 52 years and 74 years (mean age: 65.3 years). The male to female ratio was 1:1.85. The ratio of positive family history where ALS or PDC occurred within the fourth degree of the relatives was 78.4% in the patients with Kii ALS/PDC. The average duration of the illness was 6.47 years. Kii ALS/PDC was divided into five clinical subtypes, pure ALS form, ALS with dementia form, PDC with parkinsonism predominant form, PDC with dementia predominant form (that is called late-life dementia in Guam) and PDC with ALS features form. Unique pigmentary retinopathy was found in 33.3% of the patients with Kii ALS/PDC. CT/MRI images showed atrophy of the frontal and temporal lobes and SPECT images showed a decrease in the blood flow of the frontal and temporal lobes. The cardiac 123I-MIBG uptake was decreased in 4 out of 8 patients with ALS/PDC and the decrease in uptake correlated with the modified Hoehn-Yahr staging. The cardinal neuropathological features of Kii ALS/PDC were abundant neurofibrillary tangles (NFTs) associated with loss of nerve cells in the cerebral cortex and the brain stem, and findings of ALS neuropathology. Ultrastructurally, NFTs consisted of paired helical filaments. Tau protein, a main component of NFTs, was consisted of 3R and 4R tau isoforms, and phosphoryrated at 18 sites of tau phosphoryrated sites. The neurons of dentate gyrus of hippocampus and anterior horn cells were stained with anti-TDP-43 antibody. The clinical and neuropathological aspects of Kii ALS/PDC are regarded as being identical with those of Guam ALS/PDC.     

Amyotrophic lateral sclerosis/parkinsonism dementia complex: transgenic mice provide insights into mechanisms underlying a common tauopathy in an ethnic minority on Guam

Intracytoplasmic filamentous tau inclusions are neuropathological hallmarks of amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC) of Guam and the defining lesions of other neurodegenerative disorders known as tauopathies. Here we review current insights into the cell and molecular neuropathology of ALS/PDC, a common tauopathy in the Chamorro population on Guam. We also summarize recent advances in understanding this disorder through studies of transgenic (Tg) mouse models of this tauopathy. Briefly, overexpression of human tau isoforms in the central nervous system of Tg mice resulted in a neurodegenerative tauopathy with a phenotype similar to ALS/PDC. Specifically, argyrophilic, congophilic, and tau immunoreactive inclusions accumulated with age in cortical and brainstem neurons of these mice, but they were most abundant in spinal cord neurons, and the inclusions contained 10- to 20-nm tau-positive straight filaments. There also was extensive gliosis in spinal cord associated with axonal degeneration in the ventral roots, while remaining axons in spinal nerves showed a loss of microtubules and reduced fast axonal transport. With advancing age, these Tg mice showed increasing motor weakness, and this was accompanied by a progressive increase in the phosphorylation and insolubility of brain and spinal cord tau proteins. Thus, tau Tg mice recapitulate key phenotypic features of ALS/PDC neuropathology in an ethnic minority on Guam, and these animal models provide new opportunities to discover novel therapies for this and related tauopathies.