title: Myasthenia gravis in South Africans: racial differences in clinical manifestations.
abstract: We present data on the phenotypic variation in myasthenia gravis of 205 subjects from a multi-racial South African cohort. Consecutive subjects seen more than twice from 1996 to 2006, were included. Documented observational data included a myasthenia gravis and extra-ocular eye muscle score. Results showed Black subjects were more likely than Whites to develop treatment-resistant complete ophthalmoplegia and ptosis (18% vs. 2%; p=0.041). Of the 14 patients with this phenotype, 13 had generalised disease and positive AChR antibodies. Despite similar sized cohorts, White subjects were more likely than Blacks to develop generalised myasthenia poorly responsive to therapy (p=0.005). There were no significant racial differences in the time between diagnosis to initiation of therapy, or the performance and timing of thymectomy. The racial variation in some phenotypic features of myasthenia gravis and outcome to therapy, highlights the need to study biological factors in different subgroups to develop a more rational approach to immuno-suppressive therapy.
authors.affiliation: Division of Neurology, E8-74, Groote Schuur Hospital and University of Cape Town Observatory, 7925, South Africa. jeanine.heckman@uct.ac.za
authors.forename: J M
authors.initials: JM
authors.lastname: Heckmann
authors.forename: E P
authors.initials: EP
authors.lastname: Owen
authors.forename: F
authors.initials: F
authors.lastname: Little
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001323:Autoantibodies / Q000235:genetics; D044383:Black People; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D007113:Immunity, Innate; D007165:Immunosuppression Therapy / Q000592:standards; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000453:epidemiology / Q000208:ethnology* / Q000503:physiopathology*; D009886:Ophthalmoplegia / Q000453:epidemiology / Q000208:ethnology / Q000503:physiopathology; D010641:Phenotype; D044469:Racial Groups / Q000208:ethnology / Q000235:genetics; D011950:Receptors, Cholinergic / Q000276:immunology; D013019:South Africa / Q000453:epidemiology / Q000208:ethnology; D013934:Thymectomy / Q000592:standards / Q000706:statistics & numerical data; D044465:White People
chemical_list: D001323:Autoantibodies; D011950:Receptors, Cholinergic