Prevalence of myasthenia gravis in the Catalan county of Osona. / Prevalencia de miastenia gravis en la comarca de Osona (Barcelona, Cataluña).

INTRODUCTION: The reported prevalence of myasthenia gravis ranges between 5 and 24 cases per 100,000, and people over 65years account for less than 50% of all cases. The prevalence and clinical characteristics of myasthenia gravis in the county of Osona were studied in patients younger and older than 65. METHODS: The study draws from the county-based prospective myasthenia gravis register implemented by the Neurology Department at Hospital General de Vic in 1991. RESULTS: The prevalence of myasthenia gravis was 32.89×105 inhabitants (95%CI, 23.86-41.91). The standardized prevalence (European population) was 35.47×105 inhabitants (95%CI, 26.10-44.84). The ratio of women to men was 1.3. Overall, the group of patients older than 65 accounted for 62.75% of all cases. The prevalence of myasthenia gravis increased considerably in older age groups. No cases were registered among patients under 25years old, prevalence was 21.87×105 in the 25 to 64 age group, and prevalence in patients over 65 years increased to 122.35×105. The clinical characteristics prior to treatment and at the cut-off date are similar (P>.05) in patients younger than 65 and those aged 65 and older. CONCLUSIONS: These figures show the highest prevalence rate reported to date. This high prevalence is due to the rate observed among patients older than 65. These results provide a new warning that myasthenia gravis may be underdiagnosed in the elderly population.

Increase in the prevalence of multiple sclerosis over a 17-year period in Osona, Catalonia, Spain.

The prevalence of multiple sclerosis in the south of Europe seems to be higher than previously considered. This study aimed to probe a possible increase in the prevalence of multiple sclerosis (MS) in Osona over the past 17 years. This was a cross-sectional study including MS-confirmed cases from several sources of information. Crude and adjusted prevalence rates were obtained. One hundred and twenty patients fulfilled the study criteria. The crude prevalence of MS was 79.9 (95% CI: 66.3-95.6) per 100,000 inhabitants and 91.2 (95% CI: 75.5-109.2) per 100,000 among Spanish born individuals. The prevalence of multiple sclerosis cases in Osona has increased over the past 17 years to being one of the highest reported in Spain.

[Alzheimer's disease and brain evolution: is Alzheimer's disease an example of antagonistic pleiotropy?]. / Enfermedad de Alzheimer y evolución cerebral: es la enfermedad de Alzheimer un ejemplo de pleiotropía antagónica?

INTRODUCTION: Alzheimer's disease (AD) appears to be exclusive to our species. This suggests a relationship between the disease and genetic, functional and structural changes that have taken place throughout the evolution of the human brain. DEVELOPMENT: The expression of genes linked to neurotransmission, neuroplasticity, axonal transport, aerobic metabolism and neuroprotection seems to have increased within the human cerebral cortex and such phenomena represent adaptations that induce greater neuronal activity throughout a long lifespan. High levels of neuroplasticity increase neuronal vulnerability to factors capable of triggering the lesions that are typically found in AD. Several genes related to increased neuronal activity are extremely vulnerable to factors related to old age, such as oxidative stress. Some kind of dysfunction in such genes can disrupt proper regulation of a number of pathways (neuroplasticity, axonal transport) and promote the abnormal accumulation of peptides that is characteristic of AD. Possessing certain polymorphisms of neuroprotective genes or of the electron transport chain could afford protection against AD. Increased intake of animal fats could alter the balance of polyunsaturated fatty acids in the neuronal membrane and favour a higher susceptibility to oxidative stress. CONCLUSIONS: AD could constitute an example of antagonistic pleiotropy: the increased expression of advantageous genes at an early age could turn out to be harmful at an advanced age.

Onset-adjusted incidence of multiple sclerosis in the Girona province (Spain): Evidence of increasing risk in the south of Europe.

BACKGROUND: Recent studies show an increasing incidence of multiple sclerosis (MS) in southern Europe. Although by its geographical location and genetic characteristics Spain is expected to be similar to other southern European regions, data on incidence are scarce. The aim of this study was to determine the onset-adjusted incidence of MS in the Girona province in Catalonia (Spain). METHODS: A prospective incidence study pooling data from the population-based Catalonia MS Registry was performed. Incident cases were defined as patients who had the onset of symptoms compatible with a clinically isolated syndrome (CIS) suggestive of MS in 2009 and fulfilled McDonald-2005 criteria during follow-up. Age- and sex-specific incidence rates were obtained. RESULTS: The Registry included 182 patients residing in Girona that presented a CIS from January 2009 to December 2013. Fifty one patients had the onset of symptoms in 2009, of whom 27 patients fulfilled the diagnostic criteria, giving an incidence of 3.6 per 100,000 (CI 95% 2.4-5.3) inhabitants; 4.3 (CI 95% 2.5-7.1) for women and 2.9 (CI 95% 1.4-5.2) for men. The age-adjusted incidence rate for the European population was 3.29 (CI 95% 3.2-3.3). CONCLUSION: The incidence estimation derived in this study is consistent with recent epidemiological data of MS in southern Europe suggesting an increase in incidence in this region.

[Are symbolic behaviour and neuroplasticity an example of gene-culture coevolution?]. / Conducta simbólica y neuroplasticidad: un ejemplo de coevolución gen-cultura?

INTRODUCTION AND DEVELOPMENT: The brain size in the Homo genus not only has not increased during the last 150,000 years but has also experienced a slight reduction in the last 35,000 years. This reduction coincides with the generalization of the symbolic culture that was most likely established during the Upper Palaeolithic. Therefore, the cognitive capacities characteristic in the Homo sapiens could be due to structural and functional changes during the brain evolution, rather than an increase of the brain size. Dependence of symbolic culture probably required an increase of the learning and memory skills, thus demanding, at the same time, an improvement of neuroplasticity. CONCLUSIONS: The epsilon3 and epsilon2 alleles of the apolipoprotein E seem to contribute to a better synaptic repairing, in relation to the ancestral epsilon4 allele. Mutation leading to the epsilon3 allele occurred between 220,000 and 150,000 years ago. Its selection and expansion may have continued until a relatively recent period that coincides with the emergence and expansion of the complex symbolic culture. Other factors favouring neuroplasticity, such as certain polymorphisms and the expression increase of certain proteins as reelin, could also have been selected. Emergence of the symbolic behaviour and increase of its deriving technical and social complexity could have made an intense selective pressure leading to a selection of genes that induced an improvement in neuroplasticity. This would constitute an example of gene-culture coevolution.

[Multiple sclerosis epidemiological situation update: pertinence and set-up of a population based registry of new cases in Catalonia]. / Situación epidemiológica actual de la esclerosis múltiple: pertinencia y puesta en marcha de un registro poblacional de nuevos casos en Cataluña.

INTRODUCTION: The first epidemiological studies on multiple sclerosis (MS) around the world pictured a north to south latitudinal gradient that led to the first genetic and environmental pathogenic hypothesis. MS incidence seems to be increasing during the past 20 years based on recent data from prospective studies performed in Europe, America and Asia. This phenomenon could be explained by a better case ascertainment as well as a change in causal factors. The few prospective studies in our area together with the increase in the disease in other regions, justifies an epidemiological MS project in order to describe the incidence and temporal trends of MS. DEVELOPMENT: A prospective multicenter MS registry has been established according to the actual requirements of an epidemiological surveillance system. Case definition is based on the fulfillment of the McDonald diagnostic criteria. The registry setting is the geographical area of Cataluna (northeastern Spain), using a wide network of hospitals specialized in MS management. CONCLUSION: Recent epidemiological studies have described an increase in MS incidence. In order to contrast this finding in our area, we consider appropriate to set up a population based registry.

[Prevalence of cognitive deterioration in people over 80-years-old: COGMANLLEU study]. / Prevalencia de deterioro cognitivo en personas mayores de 80 años: estudio COGMANLLEU.

INTRODUCTION: We want to detect the prevalence of cognitive prevalence deterioration in the elderly population of 80-years-old or older, their grade of deterioration and the causal pathogenic entity. DESIGN: a cross-sectional population study, including a first phase of screening and a second one of diagnosis confirmation. STUDY SUBJECTS: a total of 877 elderly people of 80-years-old or older belonging to the basic health care area of Manlleu (Osona, Catalonia midlands). In the first phase, relatives and/or caregivers were interviewed, and the participating subjects underwent a set of tests. Those who obtained 24 points or less on the Mini-Mental State Examination (MMSE) and/or an equal Global Deterioration Scale (GDS) or over 3 were admitted to the second phase. During the second phase, a general and a neurological examination were performed, along with blood tests, cranial computed tomography scan and a neuropsychological study. DSM-IV criteria were used for dementia diagnosis, NINCDS-ADRA criteria for Alzheimer's disease (AD) and NINCS-AIREN for vascular dementia. RESULTS: Half of the people over 80-years-old had cognitive deterioration. One-fourth had dementia. A total of 70.3% of these dementias corresponded to AD (47.2% AD without vascular lesions and 23.1% AD with vascular lesions) and 12% corresponded to vascular dementia. The percentage of other degenerative dementias was 17.6%. Age and gender were observed to be associated to dementia. CONCLUSIONS: The prevalence of dementia in the COGMANLLEU study is similar to other European studies. AE is the most frequent dementia.

[Genetic and environmental factors that may influence in the senile form of Alzheimer's disease: nested case control studies]. / Factores genéticos y ambientales que pueden influir en la forma senil de la enfermedad de Alzheimer: estudio de casos y controles anidado.

INTRODUCTION: We identify the genetic and environmental factors associated to Alzheimer's disease (AD) in a population aged 80 years or greater. POPULATION STUDIED: subjects who participated in the COGMANLLEU study on prevalence of cognitive deterioration in Manlleu (Osona, Central Catalonia). DESIGN: nested case control studies. The subjects who were diagnosed of AD (cases) in phases 2 of said study were paired 1:1 by age and gender with control subjects who were selected from among those who had no suspicion of cognitive deterioration and who had been examined in phase 1 of the study. The participating subjects (cases and controls) and their family or caregivers were interviewed. This included psychometric tests, physical examination, biological measurements, cranial computed tomography scan and determination of ApoE genotype. RESULTS: Age is the principal factor associated to AD: risk of getting the disease is six time greater among those over 85 years (odds ratio [OR]: 6.54; 95% confidence interval [CI]: 2.05-20.81; p<0.05). Other factors associated of AD were female gender (OR: 3.17; 95 % CI: 0.80-12.50) and having been exposed to general anesthesia (OR: 3.22; 95 % CI: 1.03-10.09; p < 0.05). Arterial hypertension (AHT) presented a negative association (OR: 0.37; 95% CI: 0.10-1.31; p<0.05). An association was also observed between AD and the presence of ApoE4 allele so that the likelihood of ApoE4 in subjects with AD was three times greater than in the control group (OR: 3.44; 95% CI: 0.67-17.62). CONCLUSIONS: The results agree with the hypothesis that senile AD is a complex, multifactorial disease in which different genetic and environmental factors play a part, among which having received general anesthesia has a role that can be considered in future research.

Prevalence of multiple sclerosis in the region of Osona, Catalonia, northern Spain.

To ascertain the prevalence of multiple sclerosis in the region of Osona in Catalonia, northern Spain, an intensive study was undertaken in a small population of 72,000 people over a period of five years, using many sources of information. Patients were classified according to the Poser criteria. Most of the patients presented with mild symptoms only and many had not seen a neurologist or attended a large hospital. The prevalence of definite and probable multiple sclerosis was 58 per 100,000. This is nine to 10 times higher than had been found previously in Catalonia and is a similar prevalence to that found in southern Spain, in Sicily, and in Greek speaking Cyprus.

Myasthenia gravis: a higher than expected incidence in the elderly.

This 10-year (1991 to 2000) prospective study of MG in the county of Osona (Barcelona, Spain) reveals an annual incidence rate of 21.27 cases per million inhabitants (95% CI 13.89 to 31.16). Incidence increased from 5.03 x 10(6) in the age group of 0 to 14 years to 14.68 x 10(6) in the age group of 15 to 64 years and to 63.38 x 10(6) in the older population. These results, the highest reported to date, may be explained by the population aging.

[Deletion of 17p11.2 chromosome in Spanish families with hereditary neuropathy and abnormal sensitivity to pressure]. / Deleción del cromosoma 17p11.2 en familias españolas con neuropatía hereditaria por vulnerabilidad excesiva a la presión.

Hereditary neuropathy with abnormal liability to pressure palsies (HNPP) is a dominant autosomally transmitted disease that gives rise to foci of peripheral nerve myelination, reducing conduction and leading to episodes of palsy and sensory changes that are all linked to sensitivity to pressure and traction on the affected nerve roots. The molecular basis of HNPP has been identified as a submicroscopic deletion of the 17p11.2 chromosome in exactly the same region that it is duplicated in Charcot-Marie-Tooth disease, type 1A (CMT1A). We report genetic analyses of 13 patients (belonging to 3 families) diagnosed of HNPP by means of physical examination and electrophysiologic and morphologic tests (the last in 3 cases only). Inter- and intrafamilial variation in symptomatology was studied. Some patients presented the usual clinical signs, such as recidivating brachial plexus palsy, permanent sensory polyneuropathy, foot deformities and others that might also be found in patients with CMT1A. All the patients showed electrophysiologic signs of underlying demyelinating polyneuropathy. Genetic study centered on detecting the deletion of 17p11.2 by segregation analysis with the polymorphic markers VAW409R3a (D17S122) and EW401HE (D17S61). Our results confirmed deletion at the CTM1A location of chromosome 17p11.2 in all 13 patients examined. These data suggest that the deletion of 17p11.2 plays a causal role in HNPP and that it is the most prevalent mutation in this disease; our findings constitute new evidence of the importance of the CMT1A/HNPP locus in the formation and control of peripheral myelin and in the ultimate functioning of peripheral nerves.