View clinical trials related to Gyrate Atrophy.
Filter by:This study will evaluate the safety and effectiveness of gene therapy for patients with gyrate atrophy, an inherited condition in which areas of the retina-the inner lining of the wall of the eye-become thin. Over several decades, this degeneration of the retina causes tunnel vision, night blindness, and other vision problems. Gyrate atrophy is caused by a defect in the gene responsible for producing an enzyme, ornithine aminotransferase (OAT), that breaks down an amino acid called ornithine. As a result, excessive ornithine buildup causes the retinal thinning. Currently, this condition can only be treated with amino acid tablets and a very low-protein diet with limited fruits and vegetables and more than 2,000 calories a day from carbohydrates and fats. Some patients cannot maintain this diet, and they need another treatment. One possible alternative is to replace the defective gene with one that functions normally. Patients who have been followed in NEI's Ocular Genetics service may be eligible to participate in this study. Study patients will undergo the following gene therapy procedure: 1. Skin biopsy-A small piece of skin is surgically removed from the patient's thigh. 2. Gene transfer-Skin cells called keratinocytes are taken from the biopsied tissue and grown in the laboratory. The normal gene that produces OAT is inserted into the cells, causing them to produce more of the enzyme. 3. Skin graft-Under local anesthesia, a patch of skin about 2 1/4 inches x 2 1/4 inches is surgically removed from the upper thigh and some of the cells with increased OAT are grafted back onto this area. Patients will be followed at 1 week and 2 weeks after the procedure, then monthly for 6 months, again at 9 months and 1 year. Follow-up will continue at 1-year intervals in patients in whom the treatment is successful. During each follow-up visit patients will have 2 to 3 tablespoons of blood drawn for tests. A small biopsy (about 1/4 inch) of transplanted cells will also be done at 1 week, 1 month, 3 months, 6 months, 1 year, and each year or so thereafter. These tests will evaluate whether the treated skin cells are producing the deficient OAT enzyme and, if so, how much and for how long. They will also indicate whether the enzyme produced is sufficient to lower ornithine blood levels. Patients will also undergo various eye examinations before grafting and at scheduled follow-up visits. These tests may include electrophysiologic (ERG) testing, fundus photographs, scanning laser ophthalmoscope, visual field test, fluorescein angiogram, visual acuity, and manifest reaction.
Gyrate atrophy is a rare hereditary disease of the eye's retina (the layer of light-sensitive tissue that lines the inside of the eyeball) and choroid (a vascular layer of tissue behind the retina). Degeneration of these structures causes near-sightedness, cataracts and progressive loss of vision. This study will examine eye function and chemical and molecular abnormalities in patients with gyrate atrophy to try to better understand, diagnose, and treat the condition. Patients with other degenerative diseases of the choroid and retina, such as retinitis pigmentosa, choroideremia, and others, will also be studied for comparison. Family members of patients will be studied, when possible, to try to identify the genetic basis of the disease and gain information that will aid in genetic counseling. Study participants will undergo a physical examination and eye examination, including tests of color vision, field of vision, and ability to see in the dark. An electroretinogram and electrooculogram will measure visual cell function. Photographs of the retina will be taken. Blood will be drawn for biochemical study and gene research. Family members who agree to participate in the study will undergo the same eye tests and will also have blood drawn for genetic studies. Patients with gyrate atrophy will also be asked to undergo a small skin biopsy for biochemical and genetic study. They will provide a family history in order to draw a family tree showing how the disease is distributed among family members. Patients with gyrate atrophy may also participate in studies of the effect of vitamin B6 and diet on blood levels of the amino acid ornithine, which is elevated in patients with gyrate atrophy. Participants will take 500 mg of vitamin B6 by mouth every day for 3 to 6 months. If this study confirms a reduction of ornithine levels, then long-term studies of the vitamin as a possible treatment for the disease may be started. After the vitamin B6 study, patients will start a nearly protein-free diet to lower ornithine blood levels. More than 2,000 calories are carbohydrate and fat. Some special low-protein foods and limited fruit is included, plus amino acid supplements. Patients who have carefully adhered to this diet have lowered their ornithine levels and slowed disease progression. Patients will be hospitalized for the first 1 to 3 weeks for close monitoring with frequent urine and blood tests. When the blood ornithine level is normalized, a less restricted low protein diet will be prescribed. Participants will have monthly blood tests and a complete eye examination every 6 months to 1 year to evaluate disease progression.