Genodermatoses: Epidemiology and application of advanced laser microscopy techniques

Abstract

Genodermatoses encompass a wide range of hereditary skin disorders that significantly affect the quality of life of patients and pose substantial challenges for research. Most genodermatoses are rare, and their incidence and prevalence often are only roughly estimated. This thesis comprises three registry-based retrospective cohort studies and an experimental prospective study. The primary aim was to ascertain the incidence and prevalence of genodermatoses in Sweden, along with their healthcare needs, and to provide a comprehensive overview of these conditions. The secondary aim was to investigate the cancer risk associated with specific genodermatoses, including, porokeratosis and Darier disease. The experimental section assessed the applicability of reflectance confocal microscopy (RCM) and multiphoton microscopy (MPM) in diagnosing porokeratosis compared to traditional histopathology. We described a local patient cohort by searching the local patient registry at Sahlgrenska University Hospital in Gothenburg, Sweden. This included patients who visited the Department of Dermatology and Venereology during the period from 2016 to 2020. To gather nationwide data, we used the National Patient Registry, where we identified both inpatients and outpatients using ICD-10-SE codes between January 1, 2001, and December 31, 2020. The same patient cohorts were used for Papers I, II, and III. A total of 73 genodermatoses were registered in Sweden, and the incidence and prevalence of these diseases were reported in Paper I. The results showed that porokeratosis and Darier disease were among the most common genodermatoses. We observed an association between keratinocyte cancer and melanoma among patients with porokeratosis, as discussed in Paper II, and Darier disease, as discussed in Paper III. A prospective descriptive study presented in Paper IV evaluated the potential of the laser microscopy techniques RCM and MPM as alternatives to histopathology, with the goal of identifying a rapid, noninvasive diagnostic tool.