Does Complement Factor H Gene Polymorphism Play a Role in the Regulation of Vascular Tone in the Choroid?

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00708929

Enrollment

100

Registered

2008-07-03

Start date

2009-06-30

Completion date

2011-12-31

Last updated

2013-03-19

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Genetic Polymorphism, Macular Degeneration, Regional Blood Flow, Ocular Physiology

Keywords

Age-related macular degeneration, Complement factor H, Choroidal blood flow

Brief summary

Age related macular degeneration (AMD) is a multifactorial disease with a strong genetic component. Most importantly a genetic polymorphism in the gene encoding for the complement factor H (CFH) has been recently identified which is highly associated with an increased risk of developing AMD. This Tyr402His polymorphism located on chromosome 1q31 has been implicated to play a role in the development of the disease. Given that it is known that impaired regulation of choroidal vascular tone is present in patients with AMD, the current study seeks to investigate whether the Tyr402His polymorphism is associated with altered choroidal autoregulation in healthy subjects. For this purpose a total of 100 healthy volunteers will be included in order to test the hypothesis that an impaired regulation of choroidal blood flow is present in subjects with homozygous Tyr402His variant.

Interventions

PROCEDURESquatting

Squatting for 6 minutes

Study design

Allocation

NON_RANDOMIZED

Intervention model

PARALLEL

Primary purpose

BASIC_SCIENCE

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 45 Years

Healthy volunteers

Yes

Inclusion criteria

* Men and women aged between 18 and 35 years * Nonsmokers * Normal findings in the medical history and physical examination unless the investigator considers an abnormality to be clinically irrelevant * Normal ophthalmic findings, ametropy less than 3 diopters

Exclusion criteria

* Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study * Treatment in the previous 3 weeks with any drug * Symptoms of a clinically relevant illness in the 3 weeks before the first study day * Blood donation during the previous 3 weeks

Design outcomes

Primary

Measure	Time frame
Choroidal blood flow during isometric exercise	10 minutes
Tyr402His genotyping	screening

Secondary

Measure	Time frame
Mean arterial pressure	20 minutes
Intraocular pressure	before and after blood flow measurements
Systolic/diastolic blood pressure	20 minutes
Pulse rate	20 minutes

Countries

Austria

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026