Ocular anomalies in the alagille syndrome (arteriohepatic dysplasia)

BACKGROUND

The Alagille syndrome (arteriohepatic dysplasia) is a well-recognized multiple malformation syndrome consisting of a paucity of intrahepatic bile bile ducts, peripheral pulmonary artery hypoplasia with variable cardiac abnormalities, cholestatic facies, butterfly-like vertebral arch defects, and variable ocular anomalies, most commonly posterior embryotoxon and pigmentary retinopathy.

METHODS

The authors studied ocular findings in six patients from two families with Alagille syndrome to characterize more fully the spectrum of ocular anomalies in this disorder.

RESULTS

Ocular anomalies consisted of a peculiar mosaic pattern of iris stromal hypoplasia in all patients, posterior embryotoxon and microcornea in five patients, anomalous optic discs in five patients, regional peripapillary retinal depigmentation in three patients, and a congenital maculopathy in one patient.

CONCLUSION

The Alagille syndrome comprises a broad spectrum of ocular anomalies involving the cornea, iris, retina, and optic disc. In the setting of neonatal cholestasis, the findings of microcornea, posterior embryotoxon, mosaic iris stromal hypoplasia, regional peripapillary depigmentation, congenital macular dystrophy, and anomalous optic discs should suggest the diagnosis of Alagille syndrome.

Uncombable hair, retinal pigmentary dystrophy, dental anomalies, and brachydactyly: report of a new patient with additional findings

A new ectodermal dysplasia syndrome was reported by Bork et al. in 1987 (Hautarzt 38:342-347). The syndrome consisted of hypotrichosis with the typical SEM (scanning electron microscopy) changes of uncombable hair, retinal pigmentary dystrophy, juvenile cataract, oligodontia, brachydactyly with brachymetacarpia; it was inherited as an autosomal dominant trait. We describe a sporadic case and add further clinical findings to expand the spectrum of this rare syndrome.

A new syndrome of myelinated nerve fibers, vitreoretinopathy, and skeletal malformations

OBJECTIVE

To report a new vitreoretinopathy with high myopia, myelinated nerve fibers, and skeletal abnormalities.

PATIENTS

A mother and daughter with a previously undescribed constellation of severe vitreoretinal degeneration with high myopia and extensive myelination of the retinal nerve fiber layer, and in addition, the daughter has limb reduction deformities. Vision was severely impaired in both patients and results of electroretinography indicated the presence of cone and rod dysfunction.

CONCLUSION

This is a previously undescribed autosomal dominant vitreoretinopathy with congenital poor vision, vitreoretinal degeneration, myelinated nerve fibers, and skeletal deformities.

Ocular findings in Walker-Warburg syndrome

Ocular symptoms are frequently observed in Walker-Warburg (WWS) and associated syndromes. The majority of patients present with malformations of the anterior segment and severe retinal dysplasia. We report on the findings in a female patient with WWS who died at the age of 9 months. Major ocular findings were: severe iridocorneal malformation, a membrane-like structure of the lens and funnel-shaped retinal dysplasia. The retina presented various grades of differentiation with rosettes and atypical sequences of cells, e.g. ganglion cells intermingled between granular layers. The anterior part of the retina presented as a primitive homogeneous layer with a cell-free space that might be interpreted as the primary optic ventricle. This finding suggests that we are dealing with a primary dysplastic non-attachment rather than a real detachment of the retina in WWS. The malformation of the anterior segment was not typical of the Peters' anomaly, as usually described in WWS, but of Rieger's syndrome.

Disorder of cerebellar foliation in Walker's lissencephaly and neu-laxova syndrome

A diffuse disorder of cerebellar foliation was found in eight infants and one fetus with Walker's lissencephaly. The cerebellar cortex consisted of fused and irregularly distorted folia. In the white matter, trilaminated rings of cortex were concentrically arranged around blood vessels and mesenchymal tissue. The normal relative position of the different classes of cortical nerve cells was preserved. Cells of the external granular layer invaded the meninges and migrated along penetrating blood vessels. We believe that this foliation disorder is caused by a defect in the external basal lamina that allows adjacent folia to be fused and sulci obliterated by intrameningeal ectopias of external granule layer cells. Physical forces applied during development probably contribute to the distortion of the gyral pattern. There was a volumetric reduction of the neocerebellum, which might also be a consequence of the basal lamina defect. The cerebellum of a fetus with the Neu-Laxova syndrome showed the same abnormalities as in Walker's lissencephaly. It is postulated that these two conditions belong to a class of prenatal developmental disorders that involves a defect of the extracellular matrix.

A mutation in the Norrie disease gene (NDP) associated with X-linked familial exudative vitreoretinopathy

Familial exudative vitreoretinopathy (FEVR) is a hereditary disorder characterized by an abnormality of the peripheral retina. Both autosomal dominant (adFEVR) and X-linked (XLFEVR) forms have been described, but the biochemical defect(s) underlying the symptoms are unknown. Molecular analysis of the Norrie gene locus (NDP) in a four generation FEVR family (shown previously to exhibit linkage to the X-chromosome markers DXS228 and MAOA (Xp11.4-p11.3)) reveals a missense mutation in the highly conserved region of the NDP gene, which caused a neutral amino acid substitution (Leu124Phe), was detected in all of the affected males, but not in the unaffected family members, nor in normal controls. The observations suggest that phenotypes of both XLFEVR and Norrie disease can result from mutations in the same gene.

Myelinated nerve fibers and refractory amblyopia: a case report

We describe the case of a 3.5-year-old boy who had myelinated retinal nerve fibers and ipsilateral amblyopia refractory to occlusion therapy and simple myopic astigmatic correction. We suggest that myelinated nerve fibers may result in organic amblyopia with a resultant poor visual prognosis.

X-linked recessive primary retinal dysplasia is linked to the Norrie disease locus

X-linked primary retinal dysplasia (PRD) refers to an abnormal proliferation of retinal tissue causing either its neural elements or its glial tissue to form folds, giving rise to gliosis. A Jewish family of oriental origin was previously reported by Godel and Goodman, in which a total of five males suffer from different degrees of blindness. The authors postulated that the described findings are distinguished from Norrie disease, since in this case no clinical findings, other than those associated with the eyes, were noticed in the affected males. In addition, two of the carrier females exhibit minimal eye changes. We have performed linkage analysis of the family using the L1.28, p58-1 and m27 beta probes, and DXS426 and MAOB associated microsatellites. Our results map the gene responsible for the disorder between the MAOB and DXS426, m27 beta and p58-1 loci, on the short arm of the X chromosome at Xp11.3, which suggest the possibility that the same gene is responsible for both primary retinal dysplasia and Norrie disease.

Chorioretinal dysplasia-microcephaly-mental retardation syndrome: report of an American family

Recently we evaluated an American family with the chorioretinal dysplasia-microcephaly-mental retardation syndrome (CDMMS, McKusick #156590). The male-to-male transmission observed for the first time in the family of this report confirms autosomal dominant inheritance. Analysis of our cases and review of the literature illustrates the variable expressivity of this disorder and demonstrates the need for careful ophthalmologic evaluations of at-risk relatives in order to provide accurate recurrence risks.

Development of myelin mosaicism in the optic nerve of heterozygotes of the X-linked myelin-deficient (md) rat mutant

The oligodendrocyte population of the optic nerve has been suggested to arise either from a radial migration of neuroepithelial cells of the optic stalk or from the longitudinal migration of progenitor cells into the optic nerve from the brain, via the optic chiasm. Female heterozygotes of the X-linked myelin deficient (md) rat trait show a marked mosaic pattern of myelination of the optic nerves. This degree of mosaicism is not observed in other parts of the central nervous system. A total of 235 optic nerves from female rats of from 3 weeks to 24 months of age were examined by light microscopy. Nerves (104), from rats of all ages, showed defects in myelination consisting of distinct patches of non-myelination, often sharply demarcated from adjacent areas of normally myelinated axons. In some animals the abnormality was grossly apparent as areas of transparency within the intact optic nerves. In the majority of optic nerves showing mosaicism, defects in myelination were observed along the whole length of the nerve. However, a worsening of the defect toward the retinal end of the nerve was noted in 15 optic nerves, and an additional 11 nerves showed a defect in this region alone. It was also found that a number of rats had mosaicism in only one optic nerve. The preferential involvement of the retinal end of the optic nerves, and the asymmetrical involvement of the optic nerves within individual rats, is interpreted as indirect evidence in support of the proposed longitudinal migration of the oligodendrocyte precursor into the optic nerve.

Aicardi syndrome: more than meets the eye

An eight-month-old girl with infantile spasms and apparent blindness had electroencephalographic findings compatible with Aicardi syndrome. In addition to optic nerve hypoplasia, there were multiple congenital retinal malformations in the right eye, including chorioretinal lacunae, anomalous retinal vessels, posterior scleral ectasia, and a peripheral fibrous ridge. Magnetic resonance imaging demonstrated agenesis of the corpus callosum, absence of the septum pellucidum, optic nerve and chiasmal hypoplasia, pachygyria, cortical heterotopias, colpocephaly, and hypoplasia of the cerebellar vermis. This patient illustrates the broad spectrum of cerebroretinal malformations now known to characterize Aicardi syndrome.

Norrie disease gene: characterization of deletions and possible function

Positional cloning experiments have resulted recently in the isolation of a candidate gene for Norrie disease (pseudoglioma; NDP), a severe X-linked neurodevelopmental disorder. Here we report the isolation and analysis of human genomic DNA clones encompassing the NDP gene. The gene spans 28 kb and consists of 3 exons, the first of which is entirely contained within the 5' untranslated region. Detailed analysis of genomic deletions in Norrie patients shows that they are heterogeneous, both in size and in position. By PCR analysis, we found that expression of the NDP gene was not confined to the eye or to the brain. An extensive DNA and protein sequence comparison between the human NDP gene and related genes from the database revealed homology with cysteine-rich protein-binding domains of immediate--early genes implicated in the regulation of cell proliferation. We propose that NDP is a molecule related in function to these genes and may be involved in a pathway that regulates neural cell differentiation and proliferation.

In-utero diagnosis of Norrie disease by ultrasonography

Obstetric ultrasonography of an obligate Norrie disease carrier revealed bilateral retinal detachments in a third trimester male fetus. Postnatal examination confirmed the diagnosis of Norrie disease. DNA linkage analysis with the markers L1.28 and MAO had been uninformative for this family. This report suggests that retinal detachment occurs late in the gestation of the affected fetus.

Focal cerebral anomalies and retinal dysplasia in a 23-24-week-old fetus

A 23-24-week-old fetus was the product of a normal pregnancy terminated because of diaphragmatic hernia and hydrocephalus diagnosed by ultrasound. Karyotype on fetal blood was normal. At autopsy, hydrocephalus was associated with multiple large intrameningeal nodules and focal cerebral dysplasia resembling type II lissencephaly. In addition, many structures of the brainstem were dysmorphic and the retina showed multiple rosettes. Skeletal muscle was normal. The peculiar features described in this case pose problems for classification and genetic implications of the anomalies.

Linkage analysis of Norrie disease with an X-chromosomal ornithine aminotransferase locus

Norrie disease is a rare disease of newborn males caused by prenatal or perinatal retinal detachment, which may be associated with mental retardation, psychosis, and/or hearing loss. DXS7 (L1.28) and MAO A and B loci have been linked to the ND locus on the short arm of the X chromosome. Sequences homologous to OAT also have been mapped to the short arm of the X chromosome. We performed linkage analyses between the ND locus and one of the OAT-like clusters of sequences on the X chromosome (OATL1), using a ScaI RFLP in a ND family, and increased the previously calculated lod score (z) to over 3 (3.38; theta = 0.05). Similarly, we calculated a lod score of 4.06 (theta = 0.01) between the OATL1 and DXS7 loci. Alone, the OATL1 ScaI RFLP system is expected to be informative in 48% of females. If this system were used in combination with the DXS7 TaqI polymorphism, 71% of females would be informative for at least one of the markers and 21% would be informative for both. Because the OATL1 ScaI RFLP is a relatively common polymorphism, this system should be useful for the identification of ND carriers and affected male fetuses and newborns.

Detection of a new submicroscopic Norrie disease deletion interval with a novel DNA probe isolated by differential Alu PCR fingerprint cloning

Differential Alu PCR fingerprint cloning was used to isolate a DNA probe from the Xp11.4-->p11.21 region of the human X chromosome. This novel sequence, cpXr318 (DXS742), detects a new submicroscopic deletion interval at the Norrie disease locus (NDP). Combining our data with the consensus genetic map of the proximal short arm of the X chromosome, we propose the physical order Xcen-DXS14-DXS255-(DXS426, TIMP)-(DXS742-([MAOB-MAOA-DXS7], NDP)-DXS77-DXS228)-DXS209-DXS148-DXS196-++ +Xpter. The cpXr318 probe and a subclone from a cosmid corresponding to the DXS7 locus were converted into sequence-tagged sites. Finally, DXS742, DSX7, DXS77, and MAOA were integrated into a physical map spanning the Norrie disease locus.

The autosomal dominant familial exudative vitreoretinopathy locus maps on 11q and is closely linked to D11S533

Autosomal dominant familial exudative vitreoretinopathy (adFEVR) is a hereditary disorder characterized by the incomplete vascularization of the peripheral retina. The primary biochemical defect in adFEVR is unknown. The adFEVR locus has tentatively been assigned to 11q by linkage studies. We report the results of an extended multipoint linkage analysis of two families with adFEVR by using five markers (INT2, D11S533, D11S527, D11S35, and CD3D) from 11q13-q23. Pairwise linkage data obtained in the two families were rather similar and hence have not provided evidence for genetic heterogeneity. The highest complied two-point lod score (3.67, at a recombination fraction of .07) was obtained for the disease locus versus D11S533. Multipoint analyses showed that the adFEVR locus maps most likely, with a maximum location score of over 20, between D11S533/D11S527 and D11S35, at recombination rates of .147 and .104, respectively. Close linkage without recombination (maximum lod score 11.26) has been found between D11S533 and D11S527.

Microcephaly, lymphedema, and chorioretinal dysplasia: a distinct syndrome?

We report on 2 unrelated patients with microcephaly, lymphedema, and chorioretinal changes. They are compared with previously reported patients with microcephaly and lymphedema and microcephaly with chorioretinal changes. The question is raised whether all of these patients represent one entity or are separate syndromes. Until more data are available we propose that our patients represent a single entity.

Retinoblastoma, microphthalmia, coloboma, and neuroepithelioma of the pineal body

A one-month-old infant boy was examined early in life because his mother had bilateral retinoblastoma and his father had bilateral microphthalmia. The ophthalmologist found his right eye was normal size with a coloboma of the iris, choroid, and retina. The left eye was microphthalmic with a coloboma of the uveal tract and retina. A vascularized fluffy white mass in the posterior pole was diagnosed clinically as a retinoblastoma. The tumor regressed with radiation. When the patient was four years of age, a large tumor was found in the region of the pineal recess, causing hydrocephalus and seizures. A biopsy showed an undifferentiated malignant neuroepithelial neoplasm. The patient died within three months of diffuse central nervous system tumor. The unusual findings of a retinoblastoma in a microphthalmic eye with bilateral colobomas and a neuroepithelial neoplasm of the pineal gland are discussed.

The ocular pathology of Norrie disease in a fetus of 11 weeks' gestational age

The ocular pathology of Norrie disease was studied for the first time in a fetus of 11 weeks' gestation, following prenatal diagnosis using genetic markers for Norrie disease and elective abortion. The eyes were histologically normal, with no evidence of primary neuroectodermal maldevelopment of the retina, previously postulated to be the cause of the ocular changes. We believe that the retinal and other manifestations of Norrie disease are the result of a primary abnormality of vascular proliferation, probably in relation to persistent hyperplastic primary vitreous after approximately 14 weeks' gestation. We postulate that the ocular and otological effects of Norrie disease may be due to a genetically mediated abnormality of secretion of, or sensitivity to, angiogenic growth factors at endodermal-neuroectodermal interfaces during fetal and postnatal development.

Norrie's disease vs. PHPV: one family's dilemma

This paper presents the numerous similarities between Norrie's disease and bilateral persistent hyperplastic primary vitreous. A description of each disease is given, as well as a case report which demonstrates the difficulty in distinguishing the two disease processes when there is a negative family history of blindness. A discussion section focuses on the need for a better differential protocol for Norrie's disease, which would aid the clinician when a family history of blindness is absent.

Typical ocular coloboma affects three generations in one family

We found bilateral colobomas of the iris, choroid, retina, and optic nerve head in a son, mother, and grandmother in one pedigree. This represents a rare incidence of typical ocular coloboma in three generations.