Norrie Disease

Rare inherited neurodevelopmental disorder characterized by congenital bilateral blindness. Other features can include mental retardation, mild-to-profound hearing loss, and cataracts during early infancy. Phthisis bulbi (shrinking of the eye) has been reported.

Anderson-Warburg Syndrome; Fetal Iritis Syndrome; Whitnall-Norman Syndrome; Atrophia Bulborum Hereditaria; Congenital Progressive Oculo-Acoustico-Cerebral Degeneration; Norrie-Warburg Syndrome; Norrie Syndrome; Episkopi Blindness.

Norrie disease has been described in patients of various ethnical backgrounds (White, Hispanic, Sri Lankan, Asian, and Canadian Indian).

One hundred cases have been described. Clinical expression almost exclusively in males.

X-linked recessive disorder. Rare reports of presumed manifesting heterozygote females exist. The Norrie disease gene is located on the short arm of chromosome X (Xp11.4). It consists of three exons and encodes for a protein named norrin.

Unknown.

Based on clinical features, mode of inheritance, and genetic testing.

Characterized by microphthalmia with bilateral degeneration of the retina and vitreous humor leading to early blindness, usually within the first weeks of life. Characteristic ocular findings include retinal detachment, vitreous hemorrhage, and formation of retrolental masses. Pupils are dilated with no light reflex. Cataracts. Phthisis bulbi (shrinkage of the eyeball) develops over the first decade of life. In approximately one third of Norrie disease patients, progressive sensorineural hearing loss occurs, with age at onset varying from a few months of life to adulthood. Some degree of mental retardation is frequent (up to 50% of patients), although many individuals have normal intellectual capabilities. Several individuals with complex syndromic anomalies have been described in whom Norrie disease was part of the clinical findings. Associated anomalies in these cases included hypogonadism, increased susceptibility to infections, skeletal malformations, and a combination of facial features, including hypotelorism, narrow nasal bridge, thin upper lip, and large ears.

No literature describing anesthetic experiences in Norrie disease patients. However, adequate anxiolysis is particularly important in patients with deafness and mental retardation.

Known features of Norrie disease do not suggest an increased risk of anesthesia.

Submicroscopic deletions in the monoamine oxidase (MAO) loci have been described in Norrie disease patients. Although some of these individuals had normal MAO activities, a few were shown to have reduced to nondetectable MAO activity. It seems prudent to minimize drugs associated with an increased risk of adverse reactions when combined with MAO inhibitors such as meperidine.

X-linked Familial Exudative Vitreoretinopathy (FEVR): Disorder linked to mutations on the Norrie disease gene. Unlike Norrie disease, FEVR is not associated with hearing loss or mental retardation.

Coats Disease: Extremely rare disorder characterized by dilation of the retinal blood vessels resulting in vitreous hemorrhages. Retinal detachment has been reported. Leukokoria (white membrane or mass behind the lens) may develop.

Usher Syndrome: Characterized by hearing loss, retinitis pigmentosa, and progressive blindness.