Complex segregation analysis of facial melasma in Brazil: evidence for a genetic susceptibility with a dominant pattern of segregation

Made available in DSpace on 2018-12-11T17:22:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Despite high prevalence, the etiopathology of melasma is not fully understood. Nevertheless, many factors have been associated with the disease, including: sun exposure, sex steroids hormones, drugs, stress, and pregnancy. The high occurrence within familiars (40–60%) suggests a genetic predisposition to the disease. This study explored, through complex segregation analysis (CSA), the inheritance model that best fit the family segregation pattern of facial melasma when accounting for the main epidemiological risk factors. We evaluated 686 subjects from 67 families, and 260 (38%) of them had facial melasma. The CSA model, adjusted for age, skin phototype, sex, sun exposure at work, hormonal oral contraceptive, and pregnancy, evidenced a genetic component that was best fitted to a dominant pattern of segregation. Melasma results from an interaction between exposure factors (e.g. pregnancy, hormones, and sun exposure) over genetically predisposed individuals. Departamento de Dermatologia e Radioterapia SN FMB-Unesp, Campus de Rubião Jr. Programa de Pós-Graduação em Ciências da Saúde Escola de Medicina Pontifícia Universidade Católica do Paraná Programa de Pós-Graduação em Odontologia Escola de Ciências da Vida Pontifícia Universidade Católica do Paraná Departamento de Dermatologia e Radioterapia SN FMB-Unesp, Campus de Rubião Jr.