Absence of altered expression of optineurin in primary open angle glaucoma patients.
OBJECTIVE
To investigate the expression level of the optineurin gene (OPTN) in the blood of primary open angle glaucoma (POAG) patients to determine if altered expression is playing a role in primary open angle glaucoma systemically.


METHODS
Patients (n=47) were eligible for inclusion if they met standard clinical criteria for POAG, including age greater than 40 years, intraocular pressure ≥21 mmHg in at least one eye before treatment, normal-appearing anterior chamber angles bilaterally on gonioscopy, and optic nerve injury characteristic of POAG. Control subjects (n=27) were recruited who were free from glaucoma by examination. DNA from patient was sequenced to look for possible mutations in the coding region of OPTN or its promoter. RNA was extracted from leukocytes of patients and controls and converted to cDNA by reverse transcriptase enzyme, and quantitative PCR was used to assess expression levels of OPTN and the β-globulin gene. The ratio of OPTN expression to β-globulin gene expression for POAG patients was compared to that of controls and to clinical characteristics of POAG patients.


RESULTS
No mutation(s) were detected in any of the patients after sequencing the full OPTN gene and its promoter region. Mean OPTN (p≤0.35), and β-globulin (p≤0.48) gene expression values were statistically similar in POAG patients and controls. OPTN/β-globulin (p≤0.83) ratios were also indistinguishable between POAG patients and controls. OPTN/β-globulin ratios were not significantly associated with age, sex, or ethnicity of patients within the POAG group. Similarly, OPTN/β-globulin ratios were not significantly affected by ethnicity or clinical parameters related to POAG severity including maximum intraocular pressure, vertical cup-to-disk ratio, static perimetry mean deviation, or static perimetry pattern standard deviation.


CONCLUSIONS
OPTN expression is not altered in the blood of POAG patients, suggesting that OPTN expression is not changed systemically and implying that other mechanisms are involved in POAG pathogenesis.
Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia. abuamero@gmail.com
Khaled K
KK
Abu-Amero
Taif Anwar
TA
Azad
George L
GL
Spaeth
Jonathan
J
Myers
L Jay
LJ
Katz
Marlene
M
Moster
Thomas M
TM
Bosley
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001609:Beta-Globulins / Q000235:genetics; D016022:Case-Control Studies; D018797:Cell Cycle Proteins; D004252:DNA Mutational Analysis; D005260:Female; D015870:Gene Expression; D005902:Glaucoma, Open-Angle / Q000097:blood / Q000235:genetics*; D006801:Humans; D008297:Male; D026901:Membrane Transport Proteins; D008875:Middle Aged; D016366:Open Reading Frames; D018579:Patient Selection; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012720:Severity of Illness Index; D035582:Transcription Factor TFIIIA / Q000097:blood / Q000235:genetics*
D001609:Beta-Globulins; D018797:Cell Cycle Proteins; D026901:Membrane Transport Proteins; C409460:OPTN protein, human; D035582:Transcription Factor TFIIIA