Methodology Study of Retroviral Insertion Site Analysis in Strimvelis Gene Therapy

This non-interventional, retrospective, methodology study will use peripheral blood and bone marrow samples previously taken from subjects treated with gRV-GT. The study does not require subjects to undergo any further treatment, intervention or blood withdrawal. Eligible samples will be shipped to a central laboratory and will undergo DNA extraction prior to S-EPTS/LM-PCR analysis. Each analysis run will include a control DNA sample and up to four subject samples. Each sample will be analysed in triplicate.