Numerous disorders of the nervous system such as developmental delay, intellectual disability, epilepsy, autism, neuromuscular and neurodegenerative diseases may be due to genetic causes. Neurological manifestations with a wide spectrum of symptoms and severity are observed in many of the 8.000 diseases with assumed monogenic inheritance, and they may be part of a syndrome that affects organs outside the nervous system.
Neurogenetic disorders often display extensive genetic heterogeneity, i.e. hundreds or even thousands of genes have to be taken into account. Hence, making a clinical diagnosis may be difficult.
For the patients, a genetic diagnosis may avoid stressful and expensive further examinations (e.g. imaging, repeated hospitalizations, extensive laboratory analyses) and pave the way for an anticipatory disease management (also in cases, where no possibilities for a causal therapy are available).
In addition, the results provide important information about the recurrence risk that play a pivotal role for further family planning. In some cases, like certain defects of metabolism, ion channel and mitochondrial diseases, genetic diagnosis may also enable therapeutic options.
Familial clustering of cancers may indicate that hereditary factors play an important role for cancer development in such families. Genetic counselling and molecular genetic diagnostics may enable targeted preventive screening measures and might be important for individual treatment in some tumour entities.