Objectives: The objectives of this study are to 1) establish a cohort of participants with ABCA4-related retinopathies in anticipation of future clinical trials, 2) create a repository of plasma, DNA, and skin fibroblast samples from the accrued cohort of ABCA4-related retinopathy participants, 3) formulate clinical outcome measures for future studies, and 4) acquire and perform preliminary analyses of data that may advance our understanding of genotype-phenotype correlations in ABCA4-related retinopathies.
In addition, the skin fibroblast samples collected from participants may be used to generate iPS cells, which may be differentiated into RPE and/or neural retinal cells. These cells, if produced, will be used to analyze molecular mechanisms involved in disease pathogenesis and to perform high throughput (HTP) drug screens to identify novel potential therapeutic compounds.
Study Population: Sixty-five (65) participants, age 12 or above, with ABCA4-related retinopathies, will be initially accrued for this study. However, up to an additional five participants may be enrolled to replace participants who may withdraw from the study prior to reaching the Month 12 visit.
Design: In this natural history study, participants will be followed for 10 years. Because three years may be required to enroll 65 participants, this study will last up to 13 years. Participants will be recruited through other pre-existing NIH protocols, such as the Ocular Natural History Protocol (16-EI-0134), The Genetics of Inherited Eye Disease Protocol (15-EI-0128), the NEI Screening Protocol (08-EI-0102), and the National Ophthalmic Disease Genotyping and Phenotyping Network, Phase II protocol (eyeGENE II, 10-EI-N164), or through referral from an outside clinician after a review of pertinent medical records and genetic testing. All participants will undergo a standardized medical/ophthalmic history and a complete baseline eye examination, that may include non-invasive electrophysiology (e.g., electroretinography), psychophysiology (e.g., microperimetry, static perimetry), and diagnostic imaging examinations (e.g., optical coherence tomography).
The participants will be examined three times over the course of the first year (i.e., baseline examination, Month 6, and Month 12). After the first year, they will return to the NEI clinic on an annual basis for the next nine years. This study will require a minimum of 12 study visits. Participants may be seen at more frequent intervals at the investigators discretion, depending on the clinical and research situation. Participants will be required to submit a blood sample as part of the study for DNA and serum banking, and they will have the option to provide a 3-mm punch skin biopsy to facilitate research at a cellular level.
Outcome Measures: The primary outcome for this study is the establishment of a cohort of participants with ABCA4-related retinopathies, and the secondary outcome is the creation of a repository of plasma, DNA, and skin fibroblast samples from the accrued cohort of ABCA4-related retinopathy participants. Exploratory outcomes for this study include: 1) the formulation of clinical outcome measures for future studies and 2) the acquisition and preliminary analysis of data that may advance our understanding of genotype-phenotype correlations in ABCA4-related retinopathies. Potential exploratory outcomes include: 1) the generation of iPS cells from the skin fibroblast samples, 2) the differentiation of the generated iPS cells into RPE and/or neural retinal cells, and 3) the use of the participant-specific RPE and/or neural retinal cells to perform HTP drug screens to identify novel potential therapeutic compounds. The cells obtained in this protocol may be genetically modified and may be used for in vivo research.
