Wissinger Lab

Molecular Genetics Laboratory

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Stefanida Shliaga



First name


Position and Title Master student

Business address

Molecular Genetics Laboratory
Institute for Ophthalmic Research
Centre for Ophthalmology,
University of Tübingen
Elfriede-Aulhorn-Strasse 7
D-72076 Tübingen,

Phone: +49 (0)7071 29-80933

E-mail: stefanida.shliaga[at]med.uni-tuebingen.de

Professional background

My professional background includes experience as a laboratory physician in the Center of Genetic Diseases, where our major goal was to reveal genetic diseases in the earliest stage to avoid severe complications and disability. This kind of work was done by means of different biochemical methods (e.g. tandem mass-spectrometry, liquid and gas chromatography, different immunoassays) and molecular biology methods (i.e. PCR and NGS sequencing). My experience in this field led me to the decision to get deeper into fundamental research and continue my studies within the Master program in Molecular Medicine (Eberhard Karls Universität Tübingen) where I focused on genome data analysis and editing approaches.

Project description

Usher syndrome is an autosomal recessive disorder characterized by deafness and retinitis pigmentosa leading to progressive loss of vision. User syndrome is caused by mutations at least in 10 genes and according to clinical phenotype is divided into 3 subtypes. Mutations in USH2A gene are causative for Usher syndrome type II which is characterized by neonatal onset of hearing loss and progressive vision loss that begins in adolescence or adulthood. Pathogenic variants in USH2A gene are responsible for ~50% of all Usher and 85% of Usher type 2 cases. Specifically, the deep intronic variant USH2A:c.7595-2144A>G can account for up to ~ 4% of total USH2A alleles. It results in activation of cryptic splice site and induces the insertion of a pseudoexon. That causes formation of a premature stop-codon and subsequent degradation of the transcript via nonsense-mediated decay and absence of protein product.

The subject of my master´s project is the development of an appropriate CRISPR-Cas9 approach to rescue this pathogenic variant and restore normal mRNA maturation using innovative EDCas9, which is expected to be more efficient in comparison to classic CRISPR-Cas9 systems, and appears to be a promising therapeutic strategy in the future. The gene therapy approach using antisense oligonucleotides is considered as another promising strategy and showed first positive results in pre-clinical trials. Unlike AONs, CRISPR-Cas9 editing is realised on genome level and is expected to provide permanent effect.