ABSTRACT
BACKGROUND: Human mesial temporal lobe epilepsies (MTLE) represent the most frequent form of partial epilepsies and are frequently preceded by febrile seizures (FS) in infancy and early childhood. Genetic associations of several complement genes including its central component C3 with disorders of the central nervous system, and the existence of C3 dysregulation in the epilepsies and in the MTLE particularly, make it the C3 gene a good candidate for human MTLE. METHODOLOGY/PRINCIPAL FINDINGS: A case-control association study of the C3 gene was performed in a first series of 122 patients with MTLE and 196 controls. Four haplotypes (HAP1 to 4) comprising GF100472, a newly discovered dinucleotide repeat polymorphism [(CA)8 to (CA)15] in the C3 promoter region showed significant association after Bonferroni correction, in the subgroup of MTLE patients having a personal history of FS (MTLE-FS+). Replication analysis in independent patients and controls confirmed that the rare HAP4 haplotype comprising the minimal length allele of GF100472 [(CA)8], protected against MTLE-FS+. A fifth haplotype (HAP5) with medium-size (CA)11 allele of GF100472 displayed four times higher frequency in controls than in the first cohort of MTLE-FS+ and showed a protective effect against FS through a high statistical significance in an independent population of 97 pure FS. Consistently, (CA)11 allele by its own protected against pure FS in a second group of 148 FS patients. Reporter gene assays showed that GF100472 significantly influenced C3 promoter activity (the higher the number of repeats, the lower the transcriptional activity). Taken together, the consistent genetic data and the functional analysis presented here indicate that a newly-identified and functional polymorphism in the promoter of the complement C3 gene might participate in the genetic susceptibility to human MTLE with a history of FS, and to pure FS. CONCLUSIONS/SIGNIFICANCE: The present study provides important data suggesting for the first time the involvement of the complement system in the genetic susceptibility to epileptic seizures and to epilepsy.
Subject(s)
Complement C3/genetics , Epilepsy, Temporal Lobe/genetics , Genetic Predisposition to Disease , Promoter Regions, Genetic , Seizures, Febrile/genetics , Adolescent , Case-Control Studies , Child , Child, Preschool , Female , Genetic Variation , Humans , Male , Microsatellite Repeats , Polymorphism, Single Nucleotide , Young AdultABSTRACT
The GIGYF2 (Grb10-Interacting GYF Protein-2) gene has recently been proposed to be the responsible gene for the PARK11 locus. Ten different putative pathogenic variants were identified in cohorts of Parkinson's disease (PD) patients from Italy and France. Among these variants Asn56Ser and Asn457Thr were found repeatedly. In the present study we screened 669 PD patients (predominantly of central European origin) and 1051 control individuals for the presence of these two variants. Asn56Ser was found in one patient with a positive family history of the disease and in one control individual. The affected sister of the patient did not carry this variant. Asn457Thr was found in one patient, who was exceptional for his Egyptian origin and in three control individuals. This variant was not found in 50 control individuals from Egypt. We conclude that neither of these two variants plays a major role in the pathogenesis of PD in our study population.
