Digital Public Defence: Josephine Prener Holtan Josephine Prener Holtan at Institute of Clinical Medicine will be defending the thesis Inherited retinal diseases in Norway. Studies on phenotype and genotype characteristics for the degree of PhD (Philosophiae Doctor). 

The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

Click here to participate in the public defence

Download Zoom here

Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.

Digital Trial Lecture - time and place

See Digital Trial Lecture

Adjudication committee

  • First opponent: Consultant Eeva-Marja Sankila, Helsinki University Central Eye Hospital, Finland
  • Second opponent: Professor Kristinn Pétur Magnússon, University of Akureyri, Iceland
  • Third member and chair of the evaluation committee: Professor Ketil Størdal, Institute of Clinical Medicine, University of Oslo

Chair of defence

Associate Professor Morten Magelssen, Institute of Health and Society, University of Oslo

Principal supervisor

Associate Professor Ragnheidur Bragadottir, Institute of Clinical Medicine, University of Oslo


Inherited retinal disease is a leading cause of vision loss in children and young adults. The majority of inherited retinal diseases are untreatable, consequently leading to irreversible retinal damage and blindness. Inherited retinal diseases consist of approximately 60 clinical diagnoses with monogenic mode of inheritance, caused by variants in more than 270 genes. 

Recent advances in the understanding of the underlying molecular causes of inherited retinal diseases has facilitated the development of gene therapy. The aim of this thesis was to increase knowledge of this patient population by estimating prevalence and providing a detailed analysis of the phenotypes and genotypes of inherited retinal disease in Norway. To achieve this aim, a patient registry of inherited retinal diseases was established, including detailed clinical and genetic data of ≈ 900 patients. A population based study was performed by utilising data from the registry. Through prevalence calculations it was estimated that a minimum of 1,400 patients in Norway live with an inherited retinal disease. The clinical spectrum demonstrated heterogeneity, with over 40 clinical diagnoses registered. Non-syndromic retinitis pigmentosa was the most common clinical diagnosis and was further observed as the most genetically heterogenic diagnosis. The most common disease-causing genes found in the study population were ABCA4, USH2A and BEST1. Descriptive studies of clinical subgroups resulted in a change of phenotype classification of retinitis pigmentosa type 83 and a new phenotype-genotype subclassification of the ABCA4-retinal dystrophies. 

This thesis describes the first ever population based study that includes all inherited retinal disease diagnoses in Norway. The studies significantly increase our knowledge of this patient population and ensures knowledge required for updated clinical recommendations for genetic diagnostics, clinical follow-up as well as improved prognostic guidance. 

Additional information

contact the research support staff

Published May 27, 2021 10:23 AM - Last modified June 10, 2021 12:57 PM