Clinical implications of genetic polymorphisms in blepharospasm

Area of Science:

• Genetics
• Neurology
• Ophthalmology

Background:

• Blepharospasm (BSP) etiology is not fully understood, with limited knowledge on single-nucleotide polymorphism (SNP) contributions.
• Genetic factors are implicated in BSP and facial dystonia, necessitating further investigation into specific gene polymorphisms.

Purpose of the Study:

• To investigate the role of polymorphisms in the torsin 1A (TOR1A), dopamine receptor D2 (DRD2), and DRD5 genes in South Korean BSP patients.
• To assess the association between genetic variants of TOR1A, DRD2, and DRD5 and BSP risk, as well as response to botulinum neurotoxin A (BoNT) treatment.

Main Methods:

• A prospective case-control study involving 56 BSP patients and 115 healthy controls.
• Single nucleotide polymorphism (SNP) analysis using real-time PCR to examine TOR1A, DRD2, and DRD5 gene variants.

Main Results:

• The TOR1A rs1182CC/DRD5 rs6283TC genotype combination was associated with decreased BSP risk (AOR, 0.288; P=0.013).
• DRD5 rs6283 variants showed associations with periocular BSP and differential BoNT treatment responses.
• TOR1A rs1801968 and DRD2 rs1800497 polymorphisms were linked to superior BoNT treatment responses.

Conclusions:

• Genetic variants in TOR1A, DRD2, and DRD5 play a role in BSP susceptibility and BoNT treatment efficacy.
• DRD2 rs1800497 may confer genetic susceptibility to BSP responses to BoNT treatment.
• The TOR1A rs1182CC/DRD5 rs6283TC genotype combination is associated with BoNT efficacy in BSP patients.