Whole Genome Association Twin Study of Myopia and Glaucoma Risk Factors

Myopia and glaucoma are highly prevalent ophthalmic disorders worldwide and contribute significantly to ocular morbidity. There

is substantial evidence that genetic factors play a significant role in the development of non-syndromic myopia and glaucoma. We propose to

perform mapping studies for well-characterized twin populations in the United Kingdom and Australia in order to ultimately identify implicated

genes for these disorders and related ocular parameters. This will provide a fundamental molecular understanding of how these disorders

develop, and may lead to directed physiologic (i.e. pharmacologic, gene therapy) interventions.

Our aim is to dissect the genetic basis of the eye disorders myopia and glaucoma. Instead of limited analyses of the trait/disease in

a dichotomous manner, we are using continuous phenotypes of measures of refraction and intermediate phenotypes of glaucoma to analyze quantitative

traits in unselected population samples of volunteer twins. Achievement of this goal requires cooperative efforts and large sample sizes.

Thus, we have created an international collaboration of large complementary studies.]]>
The Twins Eye Study In Tasmania, Field Trip ProtocolsTwin Study of Glaucoma Screening ParametersAus UV Exposure QuestionnaireGuidelines for the quantification of anterior optic nerve head structuresAus Original TEST Children QuestionnaireAus Original TEST Children Recording SheetTwins Eye Study Newsletter 2006Consent FormTwins UK Volunteer Information SheetDNA Consent FormInclusion Criteria: UK twin participants, age 16-90 years, no previous intraocular surgery.

Exclusion Criteria: Non-twin relationship, age below 16 years, previous intraocular surgery, inability to understand consenting process, inability to undergo complete eye examination.]]>
We have performed classic twin studies (comparing monozygotic [MZ] correlations with DZ correlations to determine heritability) for myopia

and glaucoma by analyzing quantitative traits including: refraction, axial eye length, CCT, intraocular pressure (IOP), optic disc

area, and optic disc cup area using twins from the Australian Twin Registry and the TwinsUK Adult Twin Registry.

We have performed comprehensive ophthalmic examination of 800 DZ twin pairs (500 in Queensland and 300 in Tasmania), and 2000 DZ

twin pairs and 1000 MZ samples in the UK for glaucoma and myopia endophenotypes. These subjects have been consented for DNA genetic study.

We wish to conduct the CIDR SNP WGA scan on all of these individuals, and analyze these SNP data in both linkage and association

studies, to identify regions of the human genome likely to contain loci that influence variation in these measurements. The goal

is to identify the genes in these loci associated with a particular trait. We will also compare and analyze the genes and loci

identified by this twin genome-wide scan with other myopia and glaucoma mapping and gene discovery studies. These include the 280

multiplex pedigrees of the International Myopia Consortium (Dr. Young-PI) and the Glaucoma Inheritance Study in Tasmania

(Dr. Mackey-PI), with over 400 glaucoma pedigrees and 2000 cases of glaucoma.]]>