Norrie Disease

A number sign (#) is used with this entry because Norrie disease (ND) is caused by mutation in the NDP gene (300658), which encodes norrin, on Xp11.

Description

Norrie disease is an X-linked recessive disorder characterized by very early childhood blindness due to degenerative and proliferative changes of the neuroretina. Approximately 50% of patients show some form of progressive mental disorder, often with psychotic features, and about one-third of patients develop sensorineural deafness in the second decade. In addition, some patients have more complex phenotypes, including growth failure and seizures (Berger et al., 1992).

Warburg (1966) noted confusion of the terms 'pseudoglioma' and microphthalmia with Norrie disease in the literature. 'Pseudoglioma' is a nonspecific term for any condition resembling retinoblastoma and can have diverse causes, including inflammation, hemorrhage, trauma, neoplasia, or congenital malformation, and often shows unilateral involvement. Thus, 'pseudoglioma' is not an acceptable clinical or pathologic diagnosis (Duke-Elder, 1958).

Clinical Features

Warburg (1961) reported 7 cases of a hereditary degenerative disease in 7 generations of a Danish family. The proband was a 12-month-old boy who was normal except for lens opacities found at initial examination at 3 months of age. He had atrophic irides and the fundus was filled with a proliferating retrolental yellowish mass. At 8 months of age, the left eye was enucleated on suspicion of retinoblastoma. Histologic examination showed a hemorrhagic necrotic mass in the posterior chamber, surrounded by undifferentiated glial tissue. Histologic diagnosis was pseudotumor of the retina, retinal hyperplasia, hyperplasia of retinal, ciliary, and iris pigment epithelium, hypoplasia and necrosis of the inner layer of the retina, cataract, and phthisis bulbi. Six relatives had a similar ocular disease. Deafness developed in 5 of these 7 patients in later years, and 4 patients had decreased mental capacity. Warburg (1961) found 48 similar cases in 9 families described in the literature under different categories which she believed belonged to this disease. She suggested that the disorder be named for Gordon Norrie (1933).

Taylor et al. (1959) reported a Greek family with this condition living in Episkopi in Cyprus, where the disorder was known as 'Episkopi blindness.' The published pedigree showed 16 affected males in 5 generations. All affected males were mentally retarded.

Roberts (1937) described a pedigree, originally reported in part by Ash (1922), in which 14 males over 4 generations had microphthalmia. Affected individuals had white patches on the cornea; 2 also had cataract and 5 had nystagmus. Of the 10 individuals for which information was available, 7 were mentally retarded and 3 had normal or above-average intelligence; there was no mental retardation in the family apart from microphthalmic individuals. Waardenburg et al. (1961) thought that the cases reported by Roberts (1937) had pseudoglioma or retinal dysplasia with secondary microphthalmia. Warburg (1966) later stated that the affected persons in Roberts' pedigree were clearly instances of Norrie disease. In only about half of the cases was the eye microphthalmic, or more precisely, phthisical. Histologic study of the eye in 1 mentally retarded blind boy from this family (Whitnall and Norman, 1940) showed changes like those observed by Warburg (1966) in Norrie disease, with small optic nerves and lateral geniculate bodies.

Stephens (1947) reported a family in which 7 males over 4 generations had isolated microphthalmia. The 2 patients who were examined also had sclerocornea. Because the phenotype was transmitted only by normal mothers to their sons, Stephens (1947) suggested that it represented a sex-linked recessive trait. Warburg (1966) noted that Stephens' patients were difficult to evaluate because they were rather old at the time of first examination and information was limited to the facts that the eyes were small and corneas cloudy, but she suggested that these patients may have had Norrie disease. In an extensive pedigree from a Canadian Indian group reported by Wilson (1949), histologic changes were similar to those of ND.

In the family reported by Forssman (1960), 'pseudoglioma' was combined with progressive mental deficiency present from infancy. These patients were first described by Dahlberg-Parrow (1956). Three of the blind boys were reexamined by Warburg (1966), who concluded that the histories and ocular findings were typical of ND.

Warburg (1963) presented 2 new families with 11 patients with Norrie disease. Patients examined varied from 2 months to 58 years of age. Earliest examinations showed pseudoglioma, synechiae, and atrophy of the iris. Blindness was found during the first month of life. Cataracts were observed by 8 months, and by 10 years, the eyes were atrophic with band-shaped corneal degeneration and dense cataract. The atrophy had advanced to opaque white cornea, obliterated anterior chamber, atrophic white iris, and cataractous lens by age 50 years. Though some afflicted had normal intelligence, many were mentally deficient. The mental retardation was a deterioration inasmuch as the affected infants seemed to be normal for the first 1 to 2 years. Five of 9 in 1 family were hard of hearing and 2 of these 5 had diabetes. The mode of inheritance in both families was X-linked recessive.

Johnston et al. (1982) described 2 Irish families with 8 affected males. Harendra de Silva and de Silva (1988) described an extensively affected family in Sri Lanka.

Woodruff et al. (1993) reported a 2-year-old girl who showed severe visual impairment resulting from cataract and total retinal detachment in the right eye with a vascularized mass behind the lens, and in the left eye a retinal fold and traction retinal detachment in the temporal periphery. She had a brother and 2 maternal uncles with Norrie disease. Woodruff et al. (1993) suggested that she was an example of a manifesting heterozygote.

Lev et al. (2007) reported a male infant with Norrie disease. At birth, he was noted to have abnormal red reflex of both eyes with bilateral vitreal opacities. CT imaging of the eyes showed small lenses attached to the cornea, opacification of the lenses, corneal opacities, and synechiae. Pars plana vitrectomy and lensectomy was performed. At age 11 months, he developed myoclonic jerks and irritability. He had significant developmental delay. Over the next few months, he continued to have seizures and showed profound mental retardation. Genetic analysis identified a mutation in the NDP gene (300658.0019).

Mapping

Warburg et al. (1965) demonstrated no linkage of Norrie disease with the Xg blood groups. Moreira-Filho and Neustein (1979) described 6 brothers with what they viewed as a variant of Norrie disease because microcephaly was present in all. Negative lod scores were obtained for linkage with Xg.

Gal et al. (1985) found close linkage of Norrie disease to the L1.28/TaqI RFLP, DXS7 (maximum lod = 3.50 at theta = 0.00) on the X chromosome, suggesting that ND may be in or slightly proximal to band Xp11.3 and near a locus for retinitis pigmentosa (RP2; 300757). Gal et al. (1985) found a peak lod score of 4.1 at theta = 0.00 for linkage with DXS7, which had been localized to Xp11.3. See Bleeker-Wagemakers et al. (1985) for the full data.

Kivlin et al. (1987) stated that no recombination had been identified between ND and the DNA marker L1.28; with their data, the total lod score became 5.42. Ngo et al. (1988) and Katayama et al. (1988) found the first recombinant between Norrie disease and the DXS7 locus. The addition of their family brought a total of published informative families to 7, with a maximum lod score of 7.58 at a recombination fraction of 0.038. They stated the assignment of the DXS7 locus (defined by probe L1.28) as Xp11.3-p11.2. Ngo et al. (1989) pointed out that a single recombination event had been reported twice (Ngo et al., 1988; Katayama et al., 1988).

Gal et al. (1988) described prenatal exclusion of ND with flanking DNA markers. In an addendum, they stated that 3 families with Norrie disease and DXS7 deletion had been reported, bringing the compiled lod score for NDP vs DXS7 linkage to 11.18 at theta = 0.00. Using a RFLP detected by the ornithine amino transferase (OAT)-related DNA sequences that map to Xp (see 258870), Ngo et al. (1989) found a suggestion of linkage to the Norrie disease locus.

Wolff et al. (1992) restudied the family with 'Episkopi blindness' originally studied by Taylor et al. (1959). DNA studies revealed no deletion of any of the probes from proximal Xq. Linkage analysis yielded positive lod scores for all informative markers; e.g., with DXS255 (Xp11.22), maximum lod = 6.54 at theta = 0.0. The findings confirmed that Episkopi blindness and Norrie disease are the same entity.

Cytogenetics

Gal et al. (1985, 1986) described a 14-year-old boy with a complex syndrome dominated by Norrie disease who appeared to have a small deletion involving DXS7; the deletion had been transmitted through 3 generations. Other features included severe mental retardation, hypogonadism, growth disturbances, and increased susceptibility to infections. De la Chapelle et al. (1985) found a deletion defined by DXS7 in 4 affected members of a family with Norrie disease. Using probe L1.28 in the study of a chorion villus sample, they showed that the male fetus of a carrier woman was unaffected.

Ohba and Yamashita (1986) presented evidence suggesting that the Norrie disease locus may be at Xp11. A female infant with typical clinical and histopathologic features of vitreoretinal dysplasia was found to have a reciprocal translocation at t(X;10)(p11;p14). Her parents and sibs had normal karyotypes. Donnai et al. (1988) found that the DXS7 locus was deleted in 2 affected brothers. OTC (300461), located at Xp21.1, and DXS84, also located at Xp21.1, were intact.

In 3 generations of a Norrie disease family with 4 affected males in 3 sibships of 2 generations, Zhu et al. (1989) demonstrated deletion of 2 loci, DXS7 and DXS77. DNA studies of chorion villus biopsy material from the fetus of an obligatory carrier indicated that the fetus had inherited the normal allele from the carrier mother. This prediction was confirmed on eye examination at age 5 months. Diergaarde et al. (1989) further refined the localization of the deletion in a Dutch case of ND.

Collins et al. (1992) reported a male with Norrie disease and 2 obligate heterozygous females who were shown to have a submicroscopic deletion involving the Norrie disease locus and the loci for MAOA (309850) and MAOB (309860). The propositus was a profoundly retarded, blind male; he also had neurologic abnormalities including myoclonus and stereotypy-habit disorder, characterized as persistent stereotypic and self-injurious behavior. Both obligate carriers had a normal IQ. In the propositus, MAO activity was undetectable; in the female heterozygotes, the levels were reduced to the range observed in patients receiving MAO-inhibiting antidepressants. One of the carriers, the mother of the propositus, met diagnostic criteria for 'chronic hypomania and schizotypal features.'

Lindsay et al. (1992) did linkage studies using a highly informative microsatellite marker, DXS426, which maps proximal to DXS7 in the interval Xp11.4-p11.23. A multiply informative crossover localized the NDP gene proximal to DXS7. In conjunction with information from 2 ND patients who had a deletion for DXS7 but not for DXS426, their data indicated that the NDP gene is between DXS7 and DXS426 on proximal Xp. Chen et al. (1992) studied the end point of the deletion in a Norrie disease patient who had been shown to lack both DXS7 and MAO coding sequences, these being closely situated telomeric to the NDP locus. The pattern of retention of subclones within the deletion patient placed the end point of the deletion within 30 to 130 kb of the proximal end of a 650-kb YAC containing DXS7 and the MAO genes. They concluded that the NDP gene lay in whole or in part in the interval of approximately 250 kb within the YAC.

Molecular Genetics

Berger et al. (1992) cloned the NDP gene and identified small deletions within the gene in several patients with Norrie disease. Berger et al. (1992) identified 11 different mutations in the NDP gene (see, e.g., 300658.0001; 300658.0002) in 12 of 17 unrelated patients with Norrie disease. The fact that only one of the point mutations was detected twice was in keeping with the high proportion of new mutations expected for an X-linked disorder with greatly reduced male reproductive fitness.

Schuback et al. (1995) identified mutations in the NDP gene in 24 of 26 kindreds with Norrie disease. The authors identified 3 previously described submicroscopic deletions encompassing the entire ND gene, 6 intragenic deletions, 8 missense mutations, 6 nonsense mutations, and 1 10-bp insertion. With the exception of 2 different mutations, each found in 2 apparently unrelated kindreds, these mutations were unique. Location of most point mutations at or near cysteine residues, potentially critical in protein tertiary structure, supported a previous protein model for norrin as a member of a cystine knot growth factor family (Meitinger et al., 1993). Although genotype-phenotype correlations were limited, patients with larger submicroscopic deletions tended to have a more severe neurologic syndrome.

Isashiki et al. (1995) tabulated known mutations in the NDP gene together with the clinical manifestations.

Genotype/Phenotype Correlations

Walker et al. (1997) described 2 mutations in exon 3 of the NDP gene, a nonsense (S73X; 300658.0020) and a missense (S101F; 300658.0021) mutation, associated with severe and less severe ocular phenotype, respectively. Affected individuals in both families presented with neither the sensorineural deafness nor the mental retardation that often accompanies Norrie disease. Whereas the ocular features of the nonsense mutation were fairly typical of Norrie disease, the missense change in the C terminus was associated with milder features. Others (Chen et al., 1993; Meindl et al., 1995) had previously made the observation that mutations in the C-terminal portion of the gene product appear to result in a less severe phenotype.

History

Clarke (1898) described possibly affected females. A man blind from probable bilateral 'pseudoglioma' married his first cousin. Of their 6 children, 2 girls and 1 boy had unilateral or bilateral 'pseudoglioma.'

In his System of Ophthalmology, Duke-Elder (1958) mistakenly classified the disorder as band-shaped keratopathy.

Sims et al. (1989) demonstrated that the Norrie disease gene is distinct from the monoamine oxidase genes, although some males with atypical Norrie disease who have a submicroscopic deletion in the region of the DXS7 locus have been shown to have disruption of the MAOA and MAOB genes. The authors studied genomic DNA from 19 males in 9 families affected with Norrie disease. No deletions or rearrangements in the region of DXS7 or MAOA were observed in the DNA of these patients. Linkage analysis between the NDP gene and the DXS7 or MAOA loci showed no recombination, with a lod score of 2.80 and 2.58 at a theta of 0.0 for MAOA and DXS7, respectively. MAO activities in fibroblasts and platelets were normal.