title: Mutation analysis of VSX1 and SOD1 in Iranian patients with keratoconus.
abstract: OBJECTIVE
  To evaluate mutations in the visual system homeobox gene 1 (VSX1) and superoxide dismutase 1 (SOD1) genes with keratoconus (KTCN), direct sequencing was performed in an Iranian population.
  
  
  METHODS
  One hundred and twelve autosomal dominant KTCN patients and fifty-two unaffected individuals from twenty-six Iranian families, as well as one hundred healthy people as controls were enrolled. Genomic DNA was extracted from whole blood sample. Then to study the possible linkage between KTCN and six known loci linkage analysis was performed using 12 short tandem repeat (STR) markers. Also, the entire coding region and intron-exon boundaries of VSX1 and SOD1 were amplified by the PCR technique in each proband. Subsequently, PCR products were subjected to direct sequencing. Co-segregation analysis of the identified mutation was conducted in the family members. An Amplification Refractory Mutation System PCR (ARMS-PCR) was additionally employed for detection of the identified mutation in healthy controls.
  
  
  RESULTS
  Linkage analysis of aforementioned loci did not detect evidence for linkage to KTCN. Direct PCR sequencing revealed two single nucleotide polymorphisms (SNPs; g.1502T>G and g.9683C>T), as well as two missense mutations that have been previously reported (R166W and H244R) in VSX1. We also found three undescribed SNPs (g.4886G>A, g.4990C>G, and g.9061T>A) in SOD1. The R166W and H244R mutations were co-segregated in affected family members but not in those that were unaffected. Moreover, the ARMS-PCR strategy did not detect the identified mutations in controls.
  
  
  CONCLUSIONS
  Our data suggest a significant association between KTCN patients and VSX1 genetic alterations (p.R166W and p.H244R). Although our findings support VSX1 as a plausible candidate gene responsible for keratoconus, other chromosomal loci and genes could be involved in KTCN development. Taken together, our results suggest that p.R166W and p.H244R could have possible pathogenic influences on KTCN.
authors.affiliation: Department of Medical Genetics, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Samira
authors.initials: S
authors.lastname: Saee-Rad
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashemi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Miraftab
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Noori-Daloii
authors.forename: Morteza Hashemzadeh
authors.initials: MH
authors.lastname: Chaleshtori
authors.forename: Reza
authors.initials: R
authors.lastname: Raoofian
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Jafari
authors.forename: Wayne
authors.initials: W
authors.lastname: Greene
authors.forename: Ghasem
authors.initials: G
authors.lastname: Fakhraie
authors.forename: Farhad
authors.initials: F
authors.lastname: Rezvan
authors.forename: Mansour
authors.initials: M
authors.lastname: Heidari
mesh_terms: D001483:Base Sequence; D004252:DNA Mutational Analysis; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D020022:Genetic Predisposition to Disease; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007492:Iran; D007640:Keratoconus / Q000201:enzymology* / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D010375:Pedigree; D013482:Superoxide Dismutase / Q000235:genetics*; D000072105:Superoxide Dismutase-1; D020080:Tandem Repeat Sequences / Q000235:genetics
chemical_list: D005136:Eye Proteins; D018398:Homeodomain Proteins; C000606290:SOD1 protein, human; C491583:VSX1 protein, human; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1