Despite the progress of molecular genetics and the resulting improved possibilities for precise risk classification in affected families, the principles of formal risk assessment continue to be of great importance as a decision‐making aid for a targeted molecular genetic analysis and an adequate interpretation of molecular findings. Assuming a genetic model, which is both the basis for risk assessment and the interpretation of molecular findings is of great importance. Even in the molecular era Bayesian theorem has to be applied in monogenetic diseases like Huntington disease, spinal muscular atrophy and Duchenne muscular dystrophy. Precise risk assessment in genetic counseling often deserves Bayesian risk calculation.
Key Concepts
Risk assessment in families with genetic diseases is of great importance in spite of improved molecular diagnostics.
Risk assessment is important for both the indication of molecular diagnostics and the interpretation of possible molecular findings.
The prerequisite for the risk assessment is the assumption of a specific genetic model.
Taking a larger number of variables (e.g. incomplete penetrance, spontaneous mutations and late onset) into account, risk calculation can significantly modify a priori risks.