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Norrie`s disease is an X-linked vitreoretinal dysplasia that only affects males. Female carriers have a normal phenotype. During the first weeks of life, bilateral leucocoria appears as a result of a whitish or yellowish mass of immature retina behind the lens, on which a few vessels and elongated ciliary processes can be seen. The anterior chamber may be narrow. The disease is associated with microphtalmia, hypoplasic irides, synechiae, glaucoma, and cataract. In 1/3 of cases, bilateral perceptive deafness appears between the ages of 20 and 30 years. The disorder progresses to atrophy of the eyeball (phtisis) within a few months, causing blindness. Psychomotor retardation is frequent (65%), along with many systemic abnormalities (cardiac, pulmonary, skeletal, genitourinary, and gastrointestinal). The causative gene has recently been localised to gene map locus Xp11.4. Prenatal diagnosis identifies female carriers and is reliable. Genetic counselling and studies are important. There is no treatment for this disease. |