Retinitis pigmentosa (RP) is a genetic disorder of the eyes that causes loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision. As peripheral vision worsens, people may experience "tunnel vision". Complete blindness is uncommon. Onset of symptoms is generally gradual and often begins in childhood.
Electroretinography measures the electrical responses of various cell types in the retina, including the photoreceptors, inner retinal cells, and the ganglion cells. Electrodes are placed on the surface of the cornea or on the skin beneath the eye to measure retinal responses. Retinal pigment epithelium (RPE) responses are measured with an EOG test with skin-contact electrodes placed near the canthi. During a recording, the patient's eyes are exposed to standardized stimuli and the resulting signal is displayed showing the time course of the signal's amplitude (voltage). Signals are very small, and typically are measured in microvolts or nanovolts. The ERG is composed of electrical potentials contributed by different cell types within the retina, and the stimulus conditions can elicit stronger response from certain components.
Barakat syndrome is a rare disease characterized by hypoparathyroidism, sensorineural deafness and renal disease, and hence also known as HDR syndrome. It was first described by Amin J. Barakat et al. in 1977.
Papillorenal syndrome is an autosomal dominant genetic disorder marked by underdevelopment (hypoplasia) of the kidney and colobomas of the optic nerve.
Revesz syndrome is a fatal disease that causes exudative retinopathy and bone marrow failure. Other symptoms include severe aplastic anemia, intrauterine growth retardation, fine sparse hair, fine reticulate skin pigmentation, ataxia due to cerebellar hypoplasia, and cerebral calcifications. Its effects are similar to that of Hoyeraal-Hreidarsson syndrome. It is a variant of dyskeratosis congenita.
Conorenal syndrome, is a collection of medical conditions that seem to have a common genetic cause.