1. ¹Department of Neurology, University of Lübeck, Lübeck, Germany
2. ²Department of Human Genetics, University of Lübeck, Lübeck, Germany
3. ³Faculty of Biology, University of Belgrade, Belgrade, Serbia
4. ⁴Institute of Neurology, University of Bologna, Bologna, Italy
5. ⁵Department of Neurology, University of Genova, Genova, Italy
6. ⁶Department of Medical Genetics, University of Tübingen, Tübingen, Germany
7. ⁷Department of Neurology, General Regional Hospital, Bolzano-Bozen, Italy
8. ⁸Department of Genetic Medicine, EURAC-Research, Bolzano-Bozen, Italy

Correspondence: Dr C Klein, Department of Neurology, University of Lübeck, Ratzeburger Allee 160, Lübeck 23538, Germany. Tel: +49 451 2903 353; Fax: +49 451 2903 355; E-mail: christine.klein@neuro.uni-luebeck.de

⁹These authors contributed equally to this work

Received 21 January 2005; Revised 19 May 2005; Accepted 19 May 2005; Published online 22 June 2005.

Abstract

Recessively inherited early-onset parkinsonism (EOP) has been associated with mutations in the Parkin, DJ-1, and PINK1 genes. We studied the prevalence of mutations in all three genes in 65 Italian patients (mean age of onset: 43.25.4 years, 62 sporadic, three familial), selected by age at onset equal or younger than 51 years. Clinical features were compatible with idiopathic Parkinson's disease in all cases. To detect small sequence alterations in Parkin, DJ-1, and PINK1, we performed a conventional mutational analysis (SSCP/dHPLC/sequencing) of all coding exons of these genes. To test for the presence of exon rearrangements in PINK1, we established a new quantitative duplex PCR assay. Gene dosage alterations in Parkin and DJ-1 were excluded using previously reported protocols. Five patients (8%; one woman/four men; mean age at onset: 38.29.7 (range 25–49) years) carried mutations in one of the genes studied: three cases had novel PINK1 mutations, one of which occurred twice (homozygous c.1602_1603insCAA; heterozygous c.1602_1603insCAA; heterozygous c.836G>A), and two patients had known Parkin mutations (heterozygous c.734A>T and c.924C>T; heterozygous c.924C>T). Family history was negative for all mutation carriers, but one with a history of tremor. Additionally, we detected one novel polymorphism (c.344A>T) and four novel PINK1 changes of unknown pathogenic significance (-21G/A; IVS1+97A/G; IVS3+38_40delTTT; c.852C>T), but no exon rearrangements. No mutations were found in the DJ-1 gene. The number of mutation carriers in both the Parkin and the PINK1 gene in our cohort is low but comparable, suggesting that PINK1 has to be considered in EOP.