All human beings are genetically very similar, sharing approx. 99.9% of the DNA code. The remaining 0.1% explains the natural differences between people, including our predisposition to hereditary diseases. Although sequencing of our genetic material is becoming a routine diagnostic analysis, it is unfortunately far from simple to determine whether specific small differences in our DNA affect our risk of developing disease. The usefulness of DNA sequencing is therefore often limited to the few cases where it is already known if a gene variant increases the risk of disease.