Next-generation sequencing and functional characterization of variants of unknown significance in paediatric hepatopathies

• Applicant: Dr. Amelie Stalke
• Subject Area: Human Genetics ; Gastroenterology ; Cell Biology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 433387263

Children presenting with liver disease often have an underlying genetically determined disorder and frequently there is a delay in establishing a diagnosis, which relies on typical clinical phenotypes supported by conventional laboratory or radiological analysis. The manifesting phenotypes are divers and often overlapping making accurate diagnosis challenging. Many paediatric hepatopathies are life-threatening. Patient outcome often extremely depends on timely diagnosis. Molecular genetic diagnostics is a helpful tool to establish a diagnosis. However, a noticeable proportion of detected genetic variants have to be classified as variants of unknown significance (VUS), often leaving the clinicians as well as the patients and their families with a feeling of uncertainty. Therefore, the functional characterization of those variants is desirable to better assess the clinical impact of VUS. A high proportion of patients with paediatric hepatopathies still remain without diagnosis after routine molecular genetic panel diagnostics. As often several family members are affected, a hereditary and potentially yet unknown cause of these diseases seems likely. Here, a comprehensive genetic analysis of the patients beyond the standard panel genes is of particular interest. Aim 1: Functional characterization of VUS in distinct genes (in NOTCH2 and JAG1 associated with Alagille syndrome and in ATP7B associated with Wilson’s disease) identified in routine molecular genetic panel diagnostics using gene-specific in vitro assays as well as investigations of patient material.Aim 2: Analysis of unsolved hepatopathy cases using whole exome sequencing (WES) in trio or multi sample analysis (matching of exome data from index patients with exome data of parents and further family members). This allows narrowing down the number of possibly disease-relevant variants detected in the index exome.

• DFG Programme: Research Grants
• Co-Investigators: Dr. Eva-Doreen Pfister; Dr. Britta Skawran