Myocilin Gly252Arg mutation and glaucoma of intermediate severity in Caucasian individuals.
OBJECTIVE
To determine the phenotype of an Australian pedigree with the myocilin (MYOC) Gly252Arg mutation, comparing it with other pedigrees carrying the same mutation.


METHODS
All recruited subjects underwent a comprehensive clinical examination, including optic disc assessment, applanation tonometry, and visual field measurement. Mutation analysis was performed through direct sequencing. Haplotype analysis was performed using microsatellite markers around the MYOC gene.


RESULTS
Eight Gly252Arg mutation carriers with glaucoma were identified from the same pedigree. Carriers' mean +/- SD age at diagnosis was 46.3 +/- 11.4 years (range, 31-60 years). Highest recorded intraocular pressure ranged from 27 to 42 mm Hg (mean +/- SD, 32.4 +/- 5.6 mm Hg). Cup-disc ratios in the worst eye ranged from 0.6 to 0.9. Six of the 8 individuals had undergone filtration surgery. A common founding haplotype between MY5 and D1S218 was found for Caucasian individuals tested with this mutation. One subject was compound heterozygotic for the MYOC Gly252Arg mutation and a novel MYOC Gly244Val variant.


CONCLUSIONS
Although a common founder for Gly252Arg across Caucasian subjects was found, the phenotype from this Australian MYOC mutation-carrying pedigree is less severe than previously described. The severity of glaucoma caused by the Gly252Arg mutation may be similar to the Thr377Met MYOC mutation, yet is more severe than the most common Gln368Stop mutation.


CONCLUSIONS
Since its implication in glaucoma, much work has been performed investigating the clinical features of MYOC-related glaucoma. Given the strong genotype-phenotype correlations with MYOC disease-causing variants, health care professionals armed with such molecular information are able to accurately counsel patients on their likely disease course. Our work suggests that the disease associated with MYOC Gly252Arg is less severe than previously described in other pedigrees with this specific mutation.
Hewitt
Alex W
AW
Clinical Genetics Unit, Eye Research Australia, University of Melbourne, Royal Victorian Eye & Ear Hospital, Melbourne, Australia.
Bennett
Sonya L
SL
Richards
Julia E
JE
Dimasi
David P
DP
Booth
Adam P
AP
Inglehearn
Chris
C
Anwar
Rashida
R
Yamamoto
Tetsuya
T
Fingert
John H
JH
Héon
Elise
E
Craig
Jamie E
JE
Mackey
David A
DA
D000328:Adult; D000369:Aged, 80 and over; D003598:Cytoskeletal Proteins / Q000235:genetics*; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000145:classification / Q000235:genetics*; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D009901:Optic Nerve Diseases / Q000235:genetics; D010375:Pedigree; D010641:Phenotype; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012720:Severity of Illness Index; D014794:Visual Fields; D044465:White People; D000099179:Myocilin
D003598:Cytoskeletal Proteins; D005136:Eye Proteins; D006023:Glycoproteins; D000099179:Myocilin