1 / 23

The Eyes Have It Studying Age-Related Macular Degeneration …. The GenEpi Way

The Eyes Have It Studying Age-Related Macular Degeneration …. The GenEpi Way. Brooke Longville PhD Candidate Supervisors: Prof. Lyle Palmer (Western Australian Institute for Medical Research) Prof. Piroska Rakoczy (Lions Eye Institute) Dr Wayne Greene (Murdoch University).

tansy
Download Presentation

The Eyes Have It Studying Age-Related Macular Degeneration …. The GenEpi Way

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. The Eyes Have ItStudying Age-Related Macular Degeneration….The GenEpi Way Brooke Longville PhD Candidate Supervisors: Prof. Lyle Palmer (Western Australian Institute for Medical Research) Prof. Piroska Rakoczy (Lions Eye Institute) Dr Wayne Greene (Murdoch University) Western Australian Institute for Medical Research

  2. So… what is a macula?

  3. Your Eye: The macula contains a high concentration of rod and cone photoreceptors… This enables high quality, detailed vision- very useful!

  4. What is Age-Related Macular Degeneration (AMD)? • AMD is the leading cause of blindness in the elderly • Causes 60% of all severe vision loss • Characterized by changes in the macula: (a region of the retina responsible for our central and most important field of vision) • Deposition of waste debris (drusen) • New formation of unwanted blood vessels • Atrophy = very irregular and distressed retina surface!

  5. What causes AMD? • Complex array of risk factors suspected: • Genetic • Inherited risk (20% of sufferers have a first relative family history) • Possible correlation with other diseases/disorders such as cardiovascular, inflammatory etc.. • Environmental • SMOKING – associated with 2 - 4x increased risk • Diet • UV exposure • And many more suspects • No cure yet (hence the research…)

  6. Taking a closer look…

  7. … at a chunk of your retina.

  8. Dry AMD Wet AMD Choroidal Neovascularisation Geographic Atrophy Drusen (hard type) Drusen (Exudative/wet/soft type)

  9. This is an example of what a person with severe AMD would see

  10. Now, for a wee bit more detail…

  11. AMD- Two Forms: Dry and Wet • Dry Form • Most common form of AMD • Accounts for 90% of AMD cases • Less impact on vision than wet form • Clinical Signs: • Geographic Atrophy (GA) • shrinkage/degeneration of retinal cells, resulting in thinning of retina • Drusen • yellow deposits of debris on the retina • No known effective treatment

  12. AMD- Two Forms: Dry and Wet • Wet Form(aka Exudative/Neovascular) • Less common than dry form • Accounts of 10% of AMD cases • But more serious… • Accounts for 85% of AMD-related legal blindness • Clinical Signs: • Drusen • Choroidal Neovascularisation (CNV) • Formation of new, undesired blood vessels behind the retina • Can result in leakage or bleeding • Vision loss may be sudden and severe • Has been linked to smoking… nicotine is an angiogenic agent • Existing treatments for management of wet AMD • Laser treatment may help destroy the new blood vessels • Surgery to remove haemorrhage

  13. Impact of AMD • 800,000 Australians currently have some signs of AMD, and 2/3rds of us will experience AMD symptoms at some stage of our lives • AMD significantly impairs quality of life • Reduced ability to work, socialize, perform daily tasks independently • Economic importance • Reduced productivity • Increased medical and caring expenditure

  14. Getting down to business.(Here’s where I come in)The WA Macular Degeneration StudyAKA Brooke’s PhD research

  15. Study Hypothesis • We hypothesize that genetic factors contribute significantly to the risk of AMD development, and that these factors may be found by studying whole genome scans of AMD affected patients. • This technique has been used successfully by Haines, Klein and Edwards(2005) to discover one such genetic risk factor, a complement factor H gene variant.

  16. The AMD Study… • Prospective study: 5 years, 5000 participants • all participants are AMD patients at Lions Eye Institute • Collect blood – extract DNA • Whole Genome Scan (100,000 SNPs) • Questionnaire • Environmental factors • Clinical data • Ophthalmologists’ diagnoses and observations • Retina Photographs • Objectivity and disease progression

  17. Questionnaire content • Patient questionnaire: • Smoking -Diet • UV exposure -Education • Medications • Medical history (i.e. cancer, high blood pressure) • Ethnic background • Family history -Alcohol consumption • Clinical questionnaire: Patient’s visual acuity Observations from fluorescien angiography Observations from colour photography Diagnosis Treatments administered

  18. The big picture… AMD database DNA and Serum Specimen Data Clinical Data Genome scan – SNP analysis Environmental Data Planned future data linkage Reference location only Retina photos (LEI database) Other relevant databases Eg. Health department: -morbidity, mortality Family connections Etc..

  19. Disease Linkage • AMD study cases • linked to health dept. data • de-identified • Correlation/Linkage • Search for correlation between AMD and other diseases i.e. atherosclerosis • Search for linkage with gene variants that are known/suspected to cause disease • Heritability • Investigate AMD occurrence in related individuals

  20. Recent Research Discoveries • Complement Factor H (CFH) variant • Reported May 2005 (Haines; Klein; Edwards) • Thought to contribute significantly to risk of AMD development • Normally, CFH… • Regulates rate of complement deposition • Prevents complement buildup on host tissues • Is thought to be positively affected by 2mM [Zn] • Plasma CFH levels increase with age (of patient) • Plasma CFH levels decrease in smokers

  21. But when CFH VARIANT is present… • CFH variant is thought to be inactive or less active than normal CFH • Single amino acid differs at substrate binding site • Thus: • Complement deposition is not regulated properly • Complement buildup in host tissues more likely • As the population ages (and plasma CFH levels increase), those with defective CFH will become more apparent

  22. Aims of Study • Find genetic factors contributing to risk of AMD development • Search for the CFH variant (as described by Haines; Klein; Edwards) • Are their findings supported? • Investigate linkage/correlation between AMD and other diseases • Consider influence of other factors, such as smoking

  23. Contributors • My Supervisors (all legends): • Prof. Lyle Palmer (WAIMR) • Prof. Piroska Rakoczy (LEI) • Dr Wayne Greene (Murdoch) • Other important sources of wisdom: • Prof. Ian Constable (LEI) • LEI Clinic Staff • PathCentre Staff • The WAIMR GenEpi Group (office budskis) • Everyone else in my email inbox • Big thanks to the study patients!

More Related