New nucleic acid (I) encodes human parkin protein and includes at least one of the following genetic alterations: (a) deletion of one or more exons, optionally in combination; (b) multiplication of exons; (c) point mutations; or (d) deletion or insertion of one or more contiguous base pairs. Independent claims are also included for the following: (1) a polypeptide (II) encoded by (I); (2) an antibody (Ab) specific for (II); (3) a nucleic acid probe (Ia) that hybridizes specifically with (I); (4) primer pairs for amplifying all or part of (I); (5) a method for identifying genetic alterations in the parkin gene by amplifying at least part of the gene and detecting the specified alterations; (6) a method for diagnosing susceptibility to parkinsonism by detecting a specified alteration in the parkin gene; (7) a vector containing (I); (8) a cell containing the vector of (8); and (9) a non-human animal containing (I) in its cells.
