Background: Global variation in the incidence of multiple sclerosis (MS) is generally ascribed to differences in genetic and environmental risk factors. Here we investigate temporal trends in the incidence of MS and related disorders in British Columbia, Canada, from 1986 to 2010, focusing particularly on the Asian ethnic subpopulation. Methods: A longitudinal database was screened to identify newly diagnosed cases of MS and related disorders, including neuromyelitis optica and clinically isolated syndromes. Age-standardized, sex-specific mean annual incidence was calculated for the Asian and non-Asian population of British Columbia for 5-year intervals from 1986 to 2010. Temporal changes and cohort differences in incidence rates and demographic characteristics were evaluated. Results: During this period, the incidence of MS and related disorders in the non-Asian population remained relatively unchanged, from 10.41 (95% confidence interval [CI]: 9.87-10.97) to 9.91 (95% CI: 9.46-10.39) per 100,000 (p = 0.167). In contrast, incidence in the Asian population doubled during the same period. This increase was driven by a precipitous rise in the incidence of MS in females from 0.71 (95% CI: 0.01-1.50) to 2.08 (95% CI: 1.43-2.91) per 100,000 (p = 0.004), including both Canadian-born and immigrant Asians. The incidence of neuromyelitis optica did not change significantly during this period. Conclusions: The incidence of MS may be increasing among females in the Asian ethnic population of British Columbia.RÉSUMÉ: Incidence de la sclérose en plaques et des maladies connexes dans les populations asiatiques de la Colombie Britannique. Contexte: La variation de l'incidence de la sclérose en plaques (SP) à travers le monde est généralement attribuée à des différences dans les facteurs de risque génétiques et environnementaux. Nous avons étudié les tendances temporales de l'incidence de la SP et des maladies connexes en Colombie Britannique, au Canada, de 1986 à 2010, surtout dans les sous-populations asiatiques. Méthode: Nous avons identifié les nouveaux cas de SP et de maladies connexes, dont la névrite optique et les syndromes cliniques isolés, dans une base de données longitudinale. Nous avons calculé l'incidence annuelle moyenne par sexe, standardisée pour l'âge, dans la population asiatique et non asiatique de la Colombie Britannique, par intervalles de 5 ans, de 1986 à 2010. Nous avons évalué les changements temporaux et les différences de cohortes dans les taux d'incidence ainsi que les caractéristiques démographiques. Résultats: Pendant cette période de temps, l'incidence de la SP et des maladies connexes dans la population non asiatique est demeurée relativement inchangée, soit de 10,41 (intervalle de confiance [IC] à 95%: 9,87 à 10,97) à 9,91 (IC à 95%: 9,46 à 10,39) par 100 000 (p = 0,167) de population. Par contre, l'incidence dans la population asiatique a doublé au cours de la même période. Cette augmentation s'explique par une hausse rapide de l'incidence de la SP chez les femmes, de 0,71 (IC à 95%: ...

The symptomatic treatment of dopa-responsive dystonia (DRD) emphasizes the importance of molecular analyses of the GCH-1, TH and parkin genes. However, these analyses have not been extensively studied in Chinese DRD patients. Ten DRD families from the Han ethnic group including 14 patients and 28 clinically unaffected relatives were screened for GCH-1, TH and parkin mutations by direct sequencing, semiquantitative polymerase chain reaction (PCR), polymerase chain reaction-restriction fragment length polymorphism analysis and allele-specific PCR. Variations were verified in 200 unrelated control subjects. We have identified six novel mutations and three known mutations. The novel mutations are Leu91Val, Pro95Leu, Val204Gly and 628delC in GCH-1 gene; Gly216Ser in TH gene; and Cys253Phe in parkin gene. After molecular analyses of seven families with identified GCH-1 mutations, nine asymptomatic cases were found among 23 relatives, which confirmed the low penetrance of DRD. Unlike previous publications, male patients with GCH-1 mutations have early onset ages, while some female patients have very late onset ages in this medium-size series. Our data show that it is difficult to establish an evident genotype-phenotype correlation for DRD. However, it is necessary to know the genetic defects of DRD patients in clinics, which will help elucidate the mode of inheritance, facilitate causal therapy with levodopa and evaluate the prognosis.