Research article

Analysis of Parkinson disease patients from Portugal for mutations in SNCA, PRKN, PINK1 and LRRK2

Jose Bras^1,3 , Rita Guerreiro^1,3 , Maria Ribeiro^1,2 , Ana Morgadinho² , Cristina Januario² , Margarida Dias⁴ , Ana Calado⁴ , Cristina Semedo⁴ , Catarina Oliveira^1,2 , John Hardy³ and Andrew Singleton³

¹Center for Neurosciences and Cell Biology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal

²Neurology Service, Coimbra University Hospital, Coimbra, Portugal

³Laboratory of Neurogenetics, National Institutes on Aging, National Institutes of Health, Bethesda, Maryland, USA

⁴Neurology Service, Lisbon Hospital Center – Center Region EPE, Lisbon, Portugal

author email corresponding author email

BMC Neurology 2008, 8:1doi:10.1186/1471-2377-8-1

Published:	22 January 2008

Abstract

Background

Mutations in the genes PRKN and LRRK2 are the most frequent known genetic lesions among Parkinson's disease patients. We have previously reported that in the Portuguese population the LRRK2 c.6055G > A; p.G2019S mutation has one of the highest frequencies in Europe.

Methods

Here, we follow up on those results, screening not only LRRK2, but also PRKN, SNCA and PINK1 in a cohort of early-onset and late-onset familial Portuguese Parkinson disease patients. This series comprises 66 patients selected from a consecutive series of 132 patients. This selection was made in order to include only early onset patients (age at onset below 50 years) or late-onset patients with a positive family history (at least one affected relative). All genes were sequenced bi-directionally, and, additionally, SNCA, PRKN and PINK1 were subjected to gene dosage analysis.

Results

We found mutations both in LRRK2 and PRKN, while the remaining genes yielded no mutations. Seven of the studied patients showed pathogenic mutations, in homozygosity or compound heterozygosity for PRKN, and heterozygosity for LRRK2.

Conclusion

Mutations are common in Portuguese patients with Parkinson's disease, and these results clearly have implications not only for the genetic diagnosis, but also for the genetic counseling of these patients.