Genetic Analysis of Leucin-Rich Repeat Kinase 2 (LRRK2) G2019S Mutation in a Sample of Egyptian Patients with Parkinson's Disease, a Pilot Study

Abstract

Aim: Many causative genes and susceptibility loci have been identified to be associated with Parkinson's disease (PD) in different ethnic populations. One of these genes is the Leucin-rich repeat kinase 2 (LRRK2) gene. The G2019S substitution in that gene is the most common mutation identified to co-segregates with PD. In the North part of Egypt (Alexandria and nearby region), an incidence of 9.7% of heterozygous mutation in LRRK2 G2019S was reported in a sample of Egyptians with sporadic PD. We investigated the same mutation in 69 Egyptian patients with sporadic PD and 96 ethnically matched controls who all were inhabitants of Upper Egypt to find out if it could be a susceptibility gene for PD among Egyptians. Place and Duration of Study: Departments of pharmacology, neurology, and clinical pathology, Assiut University (Egypt) and Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany between June 2010 and September 2011. Methodology: Sixty nine patients with PD of sporadic type and ninety six controls were included in the study and all were inhabitants of Assiut Governorate and nearby region in Upper Egypt. PCR-genotyping analysis for the point mutation G2019S in the exon 41 was performed and presence or absence of mutation was confirmed by direct sequencing of the probands identified of the DNA. Results: Genotyping analysis and sequencing of DNA showed only one patient who was carrier to the mutation G2019S (1/69; incidence: 1.45%) and it was of heterozygous style. The rest of subjects (patients and control) were not carrying the mutation. This rarity of this kind of mutation among the Egyptian sample studied suggests that it may be a rare cause of PD in Upper Egypt region. However, if it is observed, it may have a trend of heterozygosity genotyping style as previously defined in the Egyptians living in the North region of Egypt Conclusion: The very low incidence of G2019S mutation in Egyptians living in Upper Egypt compared to Egyptians inhabitants in North Egypt suggests a multicenter study on a large number of Egyptians with Parkinson’s disease to reach a real incidence of that mutation and if it has (or not) a correlation to causation and course of Parkinson’s disease among Egyptians.