Examining the relationship of RFC1 gene repeat increases with sporadic parkinson's

Aim: The increase of biallelic AAGGG repeat expansions in the replication factor C subunit 1 (RFC1) gene has been demonstrated through studies to be a common cause of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), as well as late-onset ataxia. The additional clinical effects caused by RFC1 AAGGG expansions continue to be described. There are a limited number of studies investigating the prevalence of RFC1 repeat expansions in Parkinson's disease (PD). Furthermore, no data specific to our country is available. Therefore, our study aims to profile the AAGGG repeat expansions in RFC1 in individuals with PD. Method: In the study, 200 individuals diagnosed with sporadic PD and 100 control subjects were investigated for RFC1 AAGGG repeat expansions. The AAGGG repeat expansions were screened using Long-Range Polymerase Chain Reaction (PCR) and Repeat-Primed PCR techniques. Results: In the patient group, a case of homozygous pathogenic AAGGG expansion was identified (0.5%). The frequency of cases carrying heterozygous pathogenic AAGGG expansions in the patient group was determined to be 8.5%, while in the control group, this rate was 4.08%. No statistically significant difference was observed between the patient and control groups for the pathogenic AAGGGexp motif (p=0.193). Conclusion: The frequency values obtained for biallelic AAGGG expansions in our study are consistent with the literature. The higher prevalence of heterozygous carriers (8.5%) among PD patients suggests that this carrier status may be a risk factor for the disease. To confirm the identified complex motifs and validate the obtained data, further studies should be conducted with larger patient cohorts, and other motifs identified in the RFC1 gene should also be investigated.