Design: In this natural history study, participants will be followed for five years. Because three years may be required to enroll 40 participants, this study will last up to eight years. Participants will be recruited through other pre-existing NIH protocols, such as the NEI Evaluation and Treatment Trial (08-EI-0169), 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, including 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 four years. This study will require a minimum of seven 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. Since the time of the last report, we have completed enrollment in this protocol and have initiated analysis of first-year data on patients where this is available. We are specifically addressing issues related to the segmentation of OCT images and the tracking of autofluorescence images. We may be increasing the enrollment of ABCA4 patients with cone-rod degeneration in anticipation of a proof-of-concept clinical trial.
NIH ExPorter
NIH ExPorter