title: Investigations on the association between normal tension glaucoma and single nucleotide polymorphisms of the endothelin-1 and endothelin receptor genes.
abstract: OBJECTIVE
  In normal tension glaucoma (NTG), intraocular pressure is within normal the range; thus, some mechanism other than increased pressure contributes to the optic neuropathy. Endothelin may be an important contributor to the development of the optic neuropathy characteristic of glaucoma. We investigated whether polymorphisms of the endothelin-1, endothelin receptor type A, and endothelin receptor type B genes were associated with NTG.
  
  
  METHODS
  Sixty-seven Korean NTG patients and 100 healthy Korean subjects were enrolled. DNA from peripheral blood leukocytes was extracted and genotype distributions of six polymorphisms in genes encoding endothelin-1 (EDN1:c.-131dupA, EDN1:c.594G > T), endothelin receptor type A (EDNRA:c.-231G > A, EDNRA:c.*70C > G, EDNRA:c.*1222C > T), and endothelin receptor type B (EDNRB:c.831A > G) were determined. Genotype and allele distributions were compared between patients and controls. In NTG subjects, untreated baseline intraocular pressure and age at the time of diagnosis, as well as the mean deviation and pattern standard deviation values of automated static perimetry were examined for an association with these genetic polymorphisms.
  
  
  RESULTS
  The polymorphism of EDNRA:c.*1222C > T was significantly associated with NTG (p = 0.028, OR = 3.33, 95% CI 1.05-10.24). In addition, the AA genotype of the EDNRA:c.-231G > A polymorphism was associated with a lower baseline intraocular pressure than in the GG+GA genotype group (14.0 +/- 2.8 mm Hg versus 16.2 +/- 2.3 mm Hg, p = 0.047). No polymorphism was associated with visual field parameters.
  
  
  CONCLUSIONS
  A polymorphism of the endothelin receptor type A gene is associated with NTG.
authors.affiliation: Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea.
authors.forename: Seok Hwan
authors.initials: SH
authors.lastname: Kim
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Kim
authors.forename: Dong Myung
authors.initials: DM
authors.lastname: Kim
authors.forename: Hyun Su
authors.initials: HS
authors.lastname: Ko
authors.forename: Sung Yeun
authors.initials: SY
authors.lastname: Kim
authors.forename: Taiwoo
authors.initials: T
authors.lastname: Yoo
authors.forename: Seung Sik
authors.initials: SS
authors.lastname: Hwang
authors.forename: Sung Sup
authors.initials: SS
authors.lastname: Park
mesh_terms: D000328:Adult; D044466:Asian People / Q000235:genetics; D019332:Endothelin-1 / Q000235:genetics*; D005260:Female; D005838:Genotype; D005901:Glaucoma / Q000235:genetics / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D017466:Receptors, Endothelin / Q000235:genetics*
chemical_list: D019332:Endothelin-1; D017466:Receptors, Endothelin