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In previous studies of a genetic isolate, we identified significant linkage of attention deficit hyperactivity disorder (ADHD) to 4q, 5q, 8q, 11q and 17p. The existence of unique large size families linked to multiple regions, and the fact that these families came from an isolated population, we hypothesized that two-locus interaction contributions to ADHD were plausible. Several analytical models converged to show significant interaction between 4q and 11q (P

Clear evidence has been presented correlating gene polymorphisms at 6p21.3 - 21.4 (containing HLA and TNF) and the predisposition to acquire multiple sclerosis (MS). In a previous study, we found that polymorphisms at HLA DQA1 were associated with being or not being predisposed to MS in individuals inhabiting the tropics, where the prevalence of MS is significantly lower than in subtropical areas. Here, we tested the hypothesis that polymorphisms at D6S276, D6S265, D6S273 and D6S291 microsatellite loci are in strong linkage disequilibrium with a major genetic factor predisposing to MS. These microsatellites span the 6p21.3 region with intervals of 5 cM establishing particular landmarks for the HLA and TNF loci. Thirty-five MS patients and 35 controls, age, sex, social, ethnically and geographically matched healthy individuals, were studied. After testing the fit of gene frequencies to the normal distribution and performing the correlation for multiple comparisons, we found significant differences among the case and the control frequencies for the allele 202 belonging to the marker D6S276 (Pc = 0.00455) and for the allele 114 belonging to the marker D6S265 (Pc = 0.0084). For these two alleles at different loci, we found higher frequencies in the cases than in the controls. A nonsignificant p value was found in testing the existence of linkage disequilibrium among the studied loci in the cases and in the controls. In conclusion, the current study adds evidence to the established association among polymorphisms of genes located at 6p21.3 - 21.4 and MS. Furthermore, because of the distribution of the tested microsatellite loci, the more probable critical region could be correlated with the TNF neighborhood. [ABSTRACT FROM AUTHOR]

A cross sectional study was undertaken to determine the prevalence and intensity of parasitic infections in dairy cattle in the high tropics of Colombia. A total of 1003 rectal samples were collected from dairy cows at 29 farms between May and June 2014 to represent the number of farms, age groups, and size of the 65,000-cow population in the municipality of San Pedro de los Milagros. Coprological techniques were used to detect gastrointestinal nematodes, liver flukes, coccidian oocysts, and first larval stage counts of Dictyocaulus viviparus . In order of decreasing prevalence, the following parasites were detected: coccidial oocyst (36.7%; 95% CIs, 31.6-42.7), strongyle nematodes (31.6%, 27.8-35.4), liver flukes (30.9%, 21.5-37.5), cestodes (8.4%, 7.1-9.7), and D. viviparus (5.4%, 3.4-7.5). Co-infections by all possible combinations of the three most predominant groups occurred in 11 to 15% of the animals. There were significant differences in infection rates between age groups, with higher risk of liver fluke infection in animals older than 1 year of age (odds ratio (OR) = 3.2), but lower presence for coccidia and strongyles (OR = 0.19 and 0.51, respectively). For Fasciola hepatica , within-herd prevalences of > 25% in 16 farms and 94 of 281 (33.5%) animals with > 5 eggs per gram (epg) indicate that significant production losses are likely occurring. The variation in the prevalence of gastrointestinal parasites and liver flukes, together with the level of infection among age groups, could be used in integrated management programs to establish selective anthelmintic treatments and select for heritable traits of host resistance. These results serve as a baseline for future studies to determine the success of control measures and should increase awareness that subclinical parasitism is widespread in the livestock sector.

Mastitis is the main disease entity affecting dairy farms in the Colombian High Plains of northern Antioquia, Colombia. However, no previous epidemiologic studies have determined the characteristics that increase the risk of infection in this region, where manual milking is still the prevailing system of milking. A 24-mo longitudinal study was designed to identify the predominant mastitis pathogens and important herd- and cow-level risk factors. Monthly visits were made to 37 commercial dairy farms to collect herd- and cow-level data and milk samples. Herd size varied from 6 to 136 cows (mean 37.0, median 29). Herd-level factors included type of milking system (manual or mechanical) and a range of management practices recommended by the National Mastitis Council (Madison, WI) to prevent mastitis. Individual cow-level risk factors included parity, stage of lactation, breed, udder hygiene, and lameness. A logistic regression analysis was used to investigate associations between herd- and cow-level risk factors with the presence of subclinical mastitis and infection caused by Streptococcus agalactiae at the quarter level. A quarter was considered to have subclinical mastitis if it had a positive California Mastitis Test and was subsequently confirmed to have a somatic cell count of ≥200,000 cells/mL. Any cow with one or more quarters with subclinical mastitis was considered to have subclinical mastitis at the cow level. Using 17,622 cow observations, the mean prevalence of subclinical mastitis at the cow level was 37.2% (95% confidence interval: 31.2, 43.3) for the first month and did not substantially change throughout the study. The predominant microorganisms isolated from quarters meeting the subclinical mastitis definition were contagious pathogens, including Strep. agalactiae (34.4%), Corynebacterium spp. (13.2%), and Staphylococcus aureus (8.0%). Significant variables associated with subclinical mastitis risk at the quarter level included being a purebred Holstein cow, higher parity, and increased months in milk. Variables that were protective for mastitis risk included being a crossbreed cow and adequate premilking udder hygiene. Significant variables associated with Strep. agalactiae infection were higher parity, increased months in milk, and manual milking. Variables that were protective were postmilking teat dipping and adequate cleaning of the udder. The results highlight the importance of hygiene practices in contagious mastitis control in manually milked herds., (Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The Taenia solium larva causes cysticercosis in pigs, as well as economic losses for farmers and taeniosis in humans, constituting a public health problem. Infested pigs must therefore be identified before they enter the food chain. To this end, a dot blot assay was developed for the immunodiagnosis of porcine cysticercosis. A study was made of 44 pigs from different areas of Colombia that had all tested positive to cysticercosis, both by necropsy and the Western blot technique. Another group was formed comprising 44 pigs that had all tested negative to Western blot and necropsy. After analysing these 88 samples to validate the diagnostic assay, the result was a sensitivity of 86.4% and a specificity of 93.2%. The dot blot assay proved useful in diagnosing porcine cysticercosis. As the assay is easy to use in laboratories in endemic areas, as well as under field conditions, it is also appropriate for epidemiological studies.

The neural nicotinic acetylcholine receptor α4 subunit (CHRNA4), at 20q13.2-q13.3, is an important candidate gene for conferring susceptibility to attention deficit/hyperactivity disorder (ADHD). Several studies have already looked for association/linkage between ADHD and CHRNA4 in different populations. We used the Pedigree Disequilibrium Test to search for evidence of association between ADHD and six SNP marker loci in families from the isolated Paisa population. We found that the T allele of SNP rs6090384 exhibits a deficit of transmission in unaffected individuals (OR = 5.43, IC 1.54-19.13) (global P value = 0.014). We also found significant association and linkage to extended haplotypes rs2273502-rs6090384 (combination of variants C-T, respectively) (P = 0.02) and rs6090384-rs6090387 (P = 0.04) (combination of variants T-G, respectively). SNP rs6090384, variant T, has also been reported to be associated with inattention in a previous study. This makes ours the ninth study to examine the association of CHRNA4 with ADHD and the seventh one to find evidence for association in a population with a different ethnicity.

Objective: Describing knowledge and practices regarding taeniasis-cysticercosis and cysticercosis prevalence in the village of Andagoya, Colombia., Methods: The study design was qualitative and quantitative. The study population consisted of pig breeders and their families, local groups and pigs., Results: Study participants had partial knowledge of the taeniasis-cysticercosis complex. They considered taeniasis to be an illness resulting from faecal transmission and not caused by becoming infected with cysticercosis after consuming pork. Pig breeding is not carried out in confined conditions and, although breeders know the right measures for controlling some parasitic illnesses, these practices are not observed. There was 8.7% presence of T. solium antibodies in pig breeders and their relatives and 20.9% in the pigs., Conclusions: An educational programme aimed at raising the population's awareness of the taeniasis-cysticercosis complex cycle should be developed; this will facilitate control measures being applied.

Three independent complex segregation analyses found that the cause of Attention Deficit/Hyperactivity Disorder (ADHD) was the presence of major genes interacting with environmental influences. In order to identify potential environmental risk factors for ADHD in the Paisa community--a very well described, genetically isolated group--we randomly selected a sample of 486 children between 6 and 11 years of age. This group included 200 children with ADHD (149 males and 51 females) and 286 healthy controls (135 males and 151 females). The ADHD DSM-IV diagnosis was obtained using the DICA and BASC evaluation instruments, and the children's mothers or grandmothers filled out a questionnaire on each child's exposure to prenatal, neonatal, and early childhood risk factors. The data were analyzed using cross tabulation and stepwise logistic multiple-regression analyses. Cross tabulation associated ADHD with a variety of factors, including miscarriage symptoms, premature delivery symptoms, maternal respiratory viral infection, moderate to severe physical illness in the mother during gestation, prenatal cigarette and alcohol exposure, neonatal seizures, asphyxia or anoxia, severe neonatal illness, mild speech retardation, moderate brain injury, and febrile seizures (odds ratio >or= 2, P < 0.05). Stepwise logistic multiple-regression analysis also uncovered a block of variables, including male gender, maternal illnesses, prenatal alcohol exposure, mild speech retardation, febrile seizures, and moderate brain injury (odds ratio >or= 2.0, P < 0.05). Future studies on the risk of developing ADHD must include these environmental factors as covariates.

Background: Attention-deficit/hyperactivity disorder (ADHD) comorbid with oppositional defiant disorder (ODD) or conduct disorder (CD) and substance abuse/dependence seems to represent a specific subset within the phenotypic ADHD spectrum., Methods: We applied complex segregation and linkage analyses in a set of multigenerational families densely segregating ADHD comorbid with ODD, CD, alcohol abuse/dependence, and nicotine dependence., Results: Our data suggest that ADHD cosegregates with disruptive behaviors as a unique, phenotypically variable trait as evidenced by highly significant pair-wise linkages among: ADHD and ODD (logarithm of odds [LOD]=14.19), ADHD and CD (LOD=5.34), ODD and CD (LOD=6.68), and CD and alcohol abuse/dependence (LOD=3.98). In addition to previously reported ADHD susceptibility loci, we found evidence of linkage for comorbid ADHD phenotypes to loci at 8q24, 2p21-22.3, 5p13.1-p13.3, 12p11.23-13.3, 8q15, and 14q21.1-22.2. These results were replicated with an affected status phenotype derived from latent class clusters., Conclusions: Patterns of cosegregation of ADHD with comorbidities can inform our understanding of the inheritance patterns not only of ADHD but also of disruptive behavioral disorders and alcohol abuse/dependence. Refining the comorbid ADHD phenotype by determining the cosegregation profile of specific comorbidities might be a powerful tool for defining significant regions of linkage.

Introduction: Cysticercosis is a worldwide public health problem. Currently it is diagnosed by detection of specific antibodies or by imaging techniques., Objective: To evaluate an alternative diagnostic tool, a simple antibody detection assay, called Dot ELISA, for immunological diagnosis of patients with neurocysticercosis as well as for endemic population screening., Materials and Methods: The test was applied to cysticercosis patients, as well as to healthy controls and individuals with other parasitic infections. A total of 45 serum, 41 plasma and 23 cerebrospinal fluid samples were obtained from patients meeting clinical, surgical, imaging and laboratory criteria for cysticercosis. Samples were processed by enzyme-linked immune-electro-transfer blot assay and by Dot ELISA. Controls included 37 serum, 64 plasma and 17 cerebrospinal fluid samples from healthy individuals without epidemiological history for taeniosis-cysticercosis. Similarly, 43 plasma samples from patients with parasitic infections different from cysticercosis and 663 samples from population survey for cysticercosis were also evaluated., Results: A total of 933 samples were analyzed. In samples from cysticercosis patients and healthy control individuals, the Dot ELISA test showed an overall sensitivity of 80.7% (CI 95% = 80.2%-81.2%) and a specificity of 92.4% (CI 95% = 91.9%-92.8%). The Dot ELISA performed in serum had a sensitivity of 91.1%, in plasma 85.4%, and in cerebrospinal fluid 52.2%. Similarly, the same test performed in serum, plasma and cerebrospinal fluid, had a specificity of 100%, 85.9% and 100% respectively. The Dot ELISA was applied as a screening test for the diagnosis of cysticercosis in an endemic population in which 1.8% (12/663) of individuals had T. solium antibodies detected by Enzyme-linked immune-electro-transfer blot assay and showed a sensitivity of 58.3% (CI 95% = 54.0-62.7) and a specificity of 100% (CI 95% = 99.9-100.0) with a positive predictive value of 100% and a negative predictive value of 99.2%. All 43 samples from patients with parasitic infections different from cysticercosis were negative for both tests., Conclusions: These results indicated that Dot ELISA is a promising tool for the diagnosis of cysticercosis as a screening test, as well as for field epidemiological studies.

Introduction: The benign chorea hereditary (BCH, OMIM 118700) represents a childhood movement disorder characterized by its early onset, a slow progressive course (mostly stable) and the absence of mental compromise, which contrast with the clinical features exhibited by the Huntington Disease., Case Reports: Here we describe a multigenerational, extended and inbreed family belonging to a genetic isolate, the Paisa community from Antioquia Colombia, with seven children exhibiting clinical features of BCH. Even though some patients with BCH are heterozygous for a dominant mutation in the thyroid transcription factor-1 gene (TITF1), the pattern in this family resembles a recessive mode of inheritance, which suggests that genetic heterogeneity may be playing a role., Conclusion: Currently, linkage analysis is underway to determine if TITF1 is the gene responsible for this movement disorder in this family.

This study assesses the validity of the Behavioral Assessment System for Children-parent and teacher questionnaires for attention-deficit hyperactivity disorder diagnosis in a randomized sample of 344 Colombian children (145 cases, 199 controls), males and females, ages 6 to 11, with an estimated Wechsler Full Scale Intelligence Quotient over 70. The assessment protocol for both groups included psychiatric, neurologic, and psychological interviews, parent and teacher rating forms, and an Attention-Deficit Hyperactivity Disorder Checklist. All Behavioral Assessment System for Children-parent and teacher dimensions, except withdrawal and somatization, significantly differentiated cases and controls. Parents and teachers rated attention-deficit hyperactivity disorder combined type children as significantly more aggressive. Both questionnaires had good discriminant accuracy for detecting cases and control children, but accuracy for discriminating between attention-deficit hyperactivity disorder subtypes was poor. The Behavioral Assessment System for Children-parent and teacher questionnaires for 6- to 11-year-olds may be useful tools for diagnosing the presence of attention-deficit hyperactivity disorder. Additional assessment methods will be needed to discriminate between the subtypes.

Introduction: Linkage analyses provide strong evidence of how genetic factors influence epilepsy, due to the fact that they involve the determination of the cosegregation of specific marker alleles with epilepsy within families., Aims: Our aim was to determine whether there was some kind of propensity to develop generalised idiopathic epilepsy (GIE) in the 15q22.1-q25.1 region in an extended multigenerational family from the Paisa de Antioquia community, which is a genetic isolate located in Colombia that segregates for GIE and has a strong capacity to detect linkage., Patients and Methods: We selected a family containing a number of individuals suffering from epilepsy who visited the Antioquia Neurological Institute. Each affected individual had to have been diagnosed by a neurologist as suffering from non-myoclonic idiopathic epilepsy or from partial idiopathic epilepsy. All patients suspected of suffering from idiopathic epilepsy were submitted to video monitoring in order to characterise seizures electroencephalographically., Results: Of the 106 individuals in this family who were included in the family tree, 76 were genotyped; 15 of them suffered from generalised clonic tonic seizures and six were considered as being possibly affected. Lod score results were significantly negative for all the markers in relation to each of the models under consideration., Conclusions: The possibility of the genes that code for the a-3, a-5 and b-4 subunits of the neuronal nicotinic acetylcholine receptor (CHRNA3, CHRNA5 and CHRNB4) situated in the 15q region being responsible for the familial aggregation of GIE in this family, as has been suggested in previous studies in other families, was ruled out.

Attention-deficit/hyperactivity disorder (ADHD [MIM 143465]) is the most common behavioral disorder of childhood. Twin, adoption, segregation, association, and linkage studies have confirmed that genetics plays a major role in conferring susceptibility to ADHD. We applied model-based and model-free linkage analyses, as well as the pedigree disequilibrium test, to the results of a genomewide scan of extended and multigenerational families with ADHD from a genetic isolate. In these families, ADHD is highly comorbid with conduct and oppositional defiant disorders, as well as with alcohol and tobacco dependence. We found evidence of linkage to markers at chromosomes 4q13.2, 5q33.3, 8q11.23, 11q22, and 17p11 in individual families. Fine mapping applied to these regions resulted in significant linkage in the combined families at chromosomes 4q13.2 (two-point allele-sharing LOD score from LODPAL = 4.44 at D4S3248), 5q33.3 (two-point allele-sharing LOD score from LODPAL = 8.22 at D5S490), 11q22 (two-point allele-sharing LOD score from LODPAL = 5.77 at D11S1998; multipoint nonparametric linkage [NPL]-log[P value] = 5.49 at approximately 128 cM), and 17p11 (multipoint NPL-log [P value] >12 at approximately 12 cM; multipoint maximum location score 2.48 [alpha = 0.10] at approximately 12 cM; two-point allele-sharing LOD score from LODPAL = 3.73 at D17S1159). Additionally, suggestive linkage was found at chromosome 8q11.23 (combined two-point NPL-log [P value] >3.0 at D8S2332). Several of these regions are novel (4q13.2, 5q33.3, and 8q11.23), whereas others replicate already-published loci (11q22 and 17p11). The concordance between results from different analytical methods of linkage and the replication of data between two independent studies suggest that these loci truly harbor ADHD susceptibility genes.

Association between the major histocompatibility complex (MHC) and the susceptibility/resistance to acquire Chagas' disease has been largely demonstrated. To study the role of candidate genes in this susceptibility/resistance to Chagas, we designed a population-genetic-based case-control approach (chagasic n = 104 and controls n = 60) and tested the presence of genotype and linkage disequilibrium on microsatellite loci establishing specific landmarks for the MHC, interleukin (IL)-2, IL-2Rbeta chain, IL-4, IL-10, and natural resistance-associated mactophage protein 1 (NRAMP1). After demonstrating no genetic stratification among cases and controls (F(st) were not different from 0), we found significant allelic differences among chagasic patients and controls at microsatellite locus D6S291 (MHC) and at the microsatellite pointing out the IL-10. At the MHC, we found significant differences between patients and controls in Hardy-Weinberg equilibrium-expected genotype proportions. Additionally, MHC II-locus-inferred haplotypes in chagasic patients exhibited strong significant departures from the expected proportions predicted by the second Mendelian law. The linkage disequilibrium pattern at MHC involves a region of approximately 10 cM. These results replicate previous analyses and suggest that presence of epistasis between MHC with humoral systems, such as IL-10, could be underlying the susceptibility/resistance to Chagas' disease.

Introduction: Linkage analyses enable us to identify the loci that bestow susceptibility to certain diseases which are assumed to have a genetic aetiology by determining the cosegregation of alleles of specific markers within families., Aims: The aim of this study was to determine whether there is generalised idiopathic epilepsy (GIE) susceptibility in the 8q22.1 -q24.23, 16p13.3 and 21q22.3 regions within an extended multigenerational family belonging to the Paisa community in Antioquia, a genetic isolate located in Colombia segregating for GIE with a strong capacity for detecting linkage., Patients and Methods: A family with a number of individuals affected by idiopathic epilepsy who visited the Instituto Neurológico de Antioquia was selected for study. An affected individual was required to have been diagnosed by a neurologist as suffering from non-myoclonic idiopathic epilepsy or partial idiopathic epilepsy. All patients suspected of suffering from idiopathic epilepsy were submitted to video monitoring in order to characterise the seizures electroencephalographically., Results: Of the 106 individuals in this family that were included in the family tree, 76 were genotyped, 15 of whom were affected by generalised clonic tonic seizures and six were considered to be possibly affected. Results of the lod score were significantly negative for all the markers in relation to each model that was considered., Conclusions: The possibility of the genes located in the 8q22.1 -q24.23, 16p13.3 and 21q22.3 regions being responsible for the familial aggregation of GIE in this family was ruled out, which is in accordance with claims made in previous studies conducted on other families.

Our objective was to estimate the prevalence of Parkinson's disease (PD) and Parkinsonism (Ps) in Antioquia (Colombia), using the Capture-Recapture method. The two biggest institutions for attending neurological patients in Antioquia were selected as sources for the use of the Capture-Recapture method. Prevalences of PD (PPD) and Ps (PPs) were estimated according to the following expression: PPD (or PPs) = n/Nl105. The number of cases (n) of PD (or Ps), n = a + b + c + d, where a = cases identified from the two sources, b = cases identified only in the first source, c = cases identified only in the second source, and d = nondetected cases from any source = bc/a. The projected Antioquian population for the year 2000 was used as denominator. Information obtained between January 1, 1996, and December 31, 2000, was reviewed in order to identify the clinical records of all patients that fulfilled the Ps or PD criteria. General prevalence of PD in Antioquia was 30.7/100.000 (C195% = 29.2-32.2), and that of Ps was 42.1/100.000 (CI95% = 40.3-43.8). Prevalence of PD in people older than 50 years was 176.4/100.000 (CI95% = 166.6-186.3) and that of Ps was of 339.6/100.000 (C195% = 326.0-353.2). Ps and PD prevalences in Antioquia were lower than the figures reported by the National Neuroepidemiologic Study (470/100.000) and similar to the estimated prevalence of these diseases in Caucasian populations (80 to 270/100.000). These findings evidence the great variability of PD prevalence in different regions; therefore, a nationwide study is necessary to determine the prevalence of PD and Ps in Colombia.

Objective: To examine genetic variations in the region surrounding loci of the major histocompatibility complex, and to investigate the probable location of a new candidate region on the short arm of chromosome 6 predisposing to primary Sjögren's syndrome (SS)., Methods: We conducted an association study and positional candidate gene approach by microsatellite analysis. Five polymorphic microsatellite markers, D6S273, D6S439, D6S1645, D6S291, and DS61019, spanning the region 6p21.3, and establishing particular landmarks to discriminate between the human leukocyte antigen class II and tumor necrosis factor-a loci, were genotyped by polymerase chain reaction technique., Results: A total of 64 patients with primary SS and 120 matched controls were examined. There was no genetic stratification among cases and controls. Genotype distribution analysis disclosed a significantly higher number of homozygotes for D6S439 locus in patients than in controls [odds ratio (OR): 3, 95% confidence interval (CI): 1.46-6.14, p = 0.004]. Confirmation of this homozygosity was established by the gene correlation intra-locus test (Fis value = +0.233, p = 0.0007). Allele D6S439*274 was associated to disease (OR: 3, 95% CI: 1.35-6.65, p = 0.006, pc = 0.04). Among patients, no significant linkage disequilibrium (LD) value was found between the studied microsatellites and TAP, HLA-DRB1, or HLA-DQB1 loci. In controls, there was LD between D6S1645 and D6S291 loci., Conclusion: Our results indicate that D6S439 microsatellite defines a new susceptibility region for primary SS, independent of LD with TAP and HLA DQ/DR. These findings might imply that a gene surrounding this location is causally related to the disease.

Introduction: Cysticercosis (CC) caused by Taenia solium in humans and in pigs is endemic in many rural communities in developing countries. The use of Western blot assays (WB) to determine T. solium antibodies has become the best serological tool available to date for identifying positive individuals in field conditions., Aims: The aim of this study was to determine the prevalence of T. solium antibodies in humans and in pigs in two rural communities in Antioquia, Colombia., Patients, Materials and Methods: Serological identification of humans and pigs with T. solium antibodies was performed using WB assays in two communities in Ituango, Antioquia. During the study, demographic variables, housing and health conditions were taken into account. Contingency tables were drawn up using c2 to compare the proportion of seronegative individuals and seropositive individuals with headache, fainting or convulsions., Results: The prevalence of human and porcine CC obtained was 2.23 and 6.82% in Pascuita and 1.17 and 2.33% in Guacharaquero, both respectively. Of the 11 WB positive patients evaluated by imaging techniques, two individuals were found to have single calcifications in the TAC scan and RMI showed another to have an unspecified lesion. The prevalence of infection in humans and in pigs in two rural communities in the north of the district of Antioquia, Colombia, shows that CC is endemic and that steps must be taken to control it.

Introduction: Myasthenia gravis (MG), considered the commonest of all the illnesses that affect neuromuscular transmission, is a disorder in which the autoimmune system attacks the post synaptic acetylcholine receptor proteins in the end plate terminal; it is characterised by weakness and skeletal muscle fatigue, with no anomalies in reflexes, sensitivity or coordination. Epidemiological indicators, such as incidence and prevalence, are not known in Colombia. AIMS. To determine the prevalence of MG among the inhabitants of Antioquia, through the use of the capture recapture method., Patients and Methods: The capture recapture method was used for two sources, the Instituto Neurológico de Antioquia and the Hospital Universitario San Vicente de Pa l, which are the most important institutions for the diagnosis of neurological diseases in Antioquia. MG prevalence was calculated using the following formula: p= n/N 105. We examined the data from the period between 1 July 1995 and 30 June 2000 with the aim of identifying subjects who fitted the profile of MG sufferers., Results: General MG prevalence in Antioquia was 27.7 cases per million inhabitants (CI 95%= 23.2 32.2). The male/female ratio was 1:3.77., Conclusions: The estimated prevalence of MG is lower than that reported in United States and other temperate regions, where it varies between 60 and 150 cases per million. The prevalence of MG is low in Antioquia, as in other tropical areas

Individuals affected with multiple sclerosis (MS) from a genetically homogeneous Caucasian population in Antioquia, a tropical region of Colombia, were evaluated in order to observe the clinical behavior of the disease. The frequency of clinical manifestations in 65 patients with definite MS from Antioquia was compared with those reported from temperate regions. The most common manifestations were optic neuritis and motor symptoms with absence of cerebellar symptoms. This presentation is significantly different from the frequency distribution at onset in series from temperate regions. These differences suggest that environmental factors could modify the clinical expression of MS in this population.

Objective: To perform linkage analysis between the Short Tandem Repeats (STR) microsatellite markers D19S923, D19S929, D19S22, which are in strong genetic linkage to Notch3 gene in order to contrast the hypothesis that the vascular hereditary dementia phenotype described in a multigenerational extended pedigree from Colombia correspond to CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy). Even we know that using techniques as the Single Strand Conformational Polymorphisms (SSCP) could determine mutations in Notch3, the rationality of this approach is that intronic variations could not be defined and that we are interested in determine if some forms of the clinical presentation and its phenotypic variability make part of CADASIL., Introduction: The CADASIL phenotype is caused by mutations in the Notch3 gene. Clinical features of CADASIL are: 1. Recurrent cerebra-vascular episodes; 2. Migraine history; 3. History of transitory ischemic attack and, 4. Behavior changes and dementia., Material and Methods: By using SIMLINK we showed that the extended genealogy had the enough power to detect significant LOD (logarithm of oods) score values when Notch3 was considered the disorder cause. Linkage analysis was carried out by using parametric and non parametrical methods. The Elston-Stewart general method was used as the parametrical analysis and the sib pair method as the non-parametrical one. We perform simulations changing the affection status codification by including as affected or not including those individuals with migraine. Furthermore, in order to detect the stability of the results, we changed the penetrance values, the genetic frequencies on both, the marker loci and the affection locus., Results: The maximum pair-wise LOD score was 2.04 which was detected at the marker D19S23 with q= 0.11cM. This distance correspond exactly with the Notch3 location. That is 100 times more probable that there is linkage that there is not. In other words this probability could be explained as if the phenotype correspond to CADASIL than to other vascular dementia. The non parametric results were compatibles with the parametric ones. When the migraine symptom was considered as a part of the affected status, the LOD score values showed not linkage., Conclusions: The results of the linkage analysis to these STR microsatellite markers suggest that the vascular hereditary dementia phenotype described in this family correspond to CADASIL caused by a polymorphism on the Notch3 gene. On the contrary, these same results suggest that the migraine phenotype is not a part of the progressive dementia.

Introduction: Multiple sclerosis (MS) is the commonest demyelinating condition of the nervous system. It is characterized by numerous demyelinating areas or plaques of demyelination which are found dispersed throughout the nervous system. It has been shown that MS is less frequent in tropical regions than in subtropical regions. In Latin America particularly, there are some studies which show this phenomenon. However, in Colombia no studies of prevalence of MS have been done., Objective: To determine the prevalence of multiple sclerosis in five provinces of Colombia (Antioquia, Caldas, Santander, Risaralda and Bolivar)., Patients and Methods: The capture-recapture method was used for two sources to determine the number of cases defined on the criteria of Poser et al seen between July 1995 and June 2000., Results: The prevalence (cases of MS per 100,000 inhabitants) varied between 1.48 in Antioquia (95% CI 1.12; 1.78) and 4.98 in Risaralda (95% CI 3.52; 6.43). Seventy two percent were women. The regions included in this study represented 25% of the population of Colombia., Conclusions: There is a low prevalence of MS which is as expected in tropical areas. Persons with MS in these regions may be very useful in the study of other factors involved in the aetiology of MS (genetic). The capture-recapture method is an excellent tool for carrying out prevalence studies since it is cheap and requires little time.

Introduction: There are more than 40 clinical types of epilepsy classified according to aetiology and/or mode of clinical onset. The term idiopathic epilepsy is reserved for cases with convulsions but no detectable structural lesions of the brain or neurological anomalies., Development and Conclusions: In spite of many studies confirming the importance of genetic factors in the occurrence of idiopathic epilepsy, these appear to be complex and probably involve a locus of variable expression or several loci with similar phenotype expression (epistaxis). Also, environmental factors have variable effects. In recent years the principal genes involved in susceptibility to develop epilepsy have been mapped. In this way one mitochondrial and three autosomic genes have been cloned as responsible for the development of certain forms of this disorder. Also several studies of genetic linkage have given evidence, sometimes inconsistent, regarding the influence of another five loci in the susceptibility to develop epilepsy (6p21.2, 6q23-25, 8q24, 8p, 10q). On occasions the same locus has been linked with different forms of epilepsy, and on other occasions one form of epilepsy has been shown to be linked to several loci.