[Neurogenetics--the challenge for neurology. Part 1. Gene mapping and gene diagnostics]

Recent advances in gene mapping have provided distinct chromosomal locations for a number of neurological disease genes. Mapping strategies include the identification of chromosomal aberrations associated with disorders and the candidate gene approach which requires correct assumptions about the primary biochemical defect. The most successful strategy, linkage analysis, relies on family studies and allows the mapping of genes without knowledge of the molecular cause of a disorder. Once the chromosomal position for a disease gene is known, indirect DNA diagnosis becomes available, providing risk estimates for individuals in affected families. Identification of the disease gene itself allows the characterization of the protein involved and direct diagnosis at DNA and protein level, thus leading to a greater understanding of the molecular pathology of neurogenetic disorders.