Molecular genetic diagnostics is available for increasing number of genetically determined diseases. Awide spectrum
of mutations can be detected by laboratory methods. A mutation can be defined as a change in a specific DNA
sequence when compared with the reference sequence published in the gene database. However, in some cases it is
difficult to distinguish if the detected sequence variant is a causal mutation or a neutral (polymorphic) variation
without any effect on phenotype. The interpretation of rare sequence variants of unknown significance detected in
disease-causing genes becomes an increasingly important problem. Further analysis on DNA and on protein levels
with the use of bioinformatics are needed to reveal the effect of rare sequence variants. Inherited complex disorders,
for example rare hereditary forms of cancer diseases, represent a challenge tomolecular geneticists. The identification
of exact causal mutation directly responsible for the development of the disease and for the assessment of disease
risk resulting from this genetic variation has further implications. Predictive genetic diagnostics allows identify
relatives at high risk of genetically determined disease and use of targeted preventive and therapeutic approaches.
In severe cases it allows also prenatal or pre-implantation diagnostics.
mutation, polymorphism, bioinformatics, predictive program, database.