Screening for SNCA and LRRK2 mutations in Greek sporadic and autosomal dominant Parkinson’s disease: identification of two novel LRRK2 variants G. Xiromerisiou a,b , G. M. Hadjigeorgiou a , V. Gourbali a , J. Johnson b , I. Papakonstantinou c , A. Papadimitriou a and A. B. Singleton b a Neurogenetics Unit, Department of Neurology, Medical School, University of Thessaly, Larissa, Greece; b Molecular Genetics Unit, NIA, NIH, Bethesda, MD, USA; and c Department of Neurology, General Hospital of Trikala, Trikala, Greece Keywords: alpha-synuclein gene, leucine-rich repeat kinase 2 gene, mutation, Parkin- son’s disease Received 27 October 2005 Accepted 16 November 2005 Mutations in SNCA and LRRK2 genes, encoding alpha-synuclein and leucine-rich repeat kinase 2, respectively, cause autosomal dominant Parkinson’s disease (AdPD). The LRRK2 G2019S (c.6055G > A) and R1441G (c.4321C > G) mutations have also been identified in sporadic PD (sPD). We studied 55 unrelated patients with AdPD, 235 patients with sPD, and 235 healthy age- and gender-matched controls all of Greek origin. Patients with AdPD were screened for SNCA and LRRK2 mutations by direct sequencing. SNCA gene dosage analysis was also performed for AdPD using quantitative duplex polymerase chain reaction of genomic DNA. In addition, we investigated the frequency of the LRRK2 G2019S mutation in sPD. We found no missense mutations or multiplications in the SNCA gene. Here we report two novel variants, A211V (c.632C > T) and K544E (c.1630A > G) in LRRK2 gene in two patients with AdPD that was not present in controls. We identified only one patient with sPD (1/235; 0.4%) carrying the G2019S mutation. LRRK2 mutations are present in AdPD and sPD patients of Greek origin. Introduction Parkinson’s disease (PD) is the second most common neurodegenerative disorder affecting more than 1% of population older than 60 years of age [1]. About 15% of PD patients have a first-degree relative with disease [2]. The alpha-synuclein gene (SNCA) was the first to be linked to an autosomal dominant form of PD (AdPD). To date three missense mutations (A53T, A30P and E46K) [3–5] and several multiplications of the SNCA gene [6–8] in AdPD families have been reported. Recently, the identification of pathogenic mutations in a novel gene, the leucine-rich repeat kinase 2 gene (LRRK2) in families with AdPD from different popu- lations heralds an exciting time in the field of neuro- genetics [9,10]. An heterozygous LRRK2 mutation (G2019S) was identified in 1.6% of patients with sporadic PD (sPD) and in 5–6% of those with familial PD [11–14]; this is the most common LRRK2 mutation identified to date. The A53T mutation in SNCA has been identified as a frequent cause of AdPD in several Greek families [15,16]. As mutations in LRRK2 are a newly identified cause of AdPD, we were prompted to investigate the frequency of mutations in these two genes in a Greek population. Materials and methods Subjects Two hundred and thirty-five patients with sPD (112 fe- male and 123 male) and 55 unrelated PD patients (20 male and 35 female) with family history of autosomal dominant inheritance were included in this study. Ten (18.2%) patients with AdPD had one affected relative; 19 (34.5%) had two affected relatives; 19 (34.5%) had three affected relatives; six (10.9%) had five affected relatives; one (1.8%) had seven affected relatives. The diagnosis of PD was based on published criteria [17]. All patients were residents of Thessaly (Central Greece; 150 000 inhabit- ants) and were identified during a 3-year period (2001– 2004) in the outpatient clinic for movement disorders in University Hospital in Larissa (the only clinic for movement disorders in Thessaly) and were followed up for at least 1–3 years. The patients with sporadic disease were on average 69 ± 9.7 SD (range 44–95) years old at the time of initial examination whilst their mean age at onset of disease was 63.3 ± 9.6 SD years. The patients with family history of dominant inheritance were on average 70 ± 9.7 SD (range 40–82) years old at time of initial examination whilst their mean age at onset of disease was 60 ± 9.2 SD (38–80) years. Correspondence: Georgios M. Hadjigeorgiou MD, Neurogenetics Unit, Department of Neurology, Medical School, University of Thessaly, Papakyriazi 22 Street, Larissa 41222, Greece (tel.: +30 2410 682320; fax: +30 2410 611097; e-mail: gmhadji@med.uth.gr). Ó 2006 EFNS 7 European Journal of Neurology 2007, 14: 7–11 doi:10.1111/j.1468-1331.2006.01551.x