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PubMed2000

[Cockayne's syndrome with unusual retinal involvement (report of one family)].

Cockayne's syndrome is a very rare autosomal recessive affection. Ocular involvement is an essential element for positive diagnosis; the retina shows a typical salt and pepper retinitis with optical atrophy. We report a family with four brothers who had Cockayne's syndrome with unusual retinal involvement. The patients' parents were first cousins. Ophthalmologic examination of the mother showed unilateral left pigmentary retinopathy localized in the peripapillary region. The father's ophthalmological examination was normal. The four brothers presented disharmonious dwarfism, cutaneous hyperpigmentation of skin areas exposed to sun with old-appearance of the skin, sensorineural deafness, kyphoscoliosis, a cerebellar syndrome and mental retardation. The ophthalmological examination showed hypermetropia in all four brothers and bilateral maculopathy with no papillary or vascular abnormalities. The electroretinogram was in favor of cone dystrophy. Computed tomography showed one case of calcifications of the basal ganglia and cerebral atrophy. The karyotypes of the four brothers and the mother were normal. We discuss the ocular symptoms and the etiopathogenesis of this syndrome.

Adolescent↗

PubMed1999

New criteria for improved diagnosis of Bardet-Biedl syndrome: results of a population survey.

Bardet-Biedl syndrome (BBS) is an autosomal recessive condition characterised by rod-cone dystrophy, postaxial polydactyly, central obesity, mental retardation, hypogonadism, and renal dysfunction. BBS expression varies both within and between families and diagnosis is often difficult. We sought to define the condition more clearly by studying 109 BBS patients and their families, the largest population surveyed to date. The average age at diagnosis was 9 years, which is late for such a debilitating condition, but the slow development of the clinical features of BBS probably accounts for this. Postaxial polydactyly had been present in 69% of patients at birth, but obesity had only begun to develop at around 2-3 years, and retinal degeneration had not become apparent until a mean age of 8.5 years. Our study identified some novel clinical features, including neurological, speech, and language deficits, behavioural traits, facial dysmorphism, and dental anomalies. In the light of these features we propose a revision of the diagnostic criteria, which may facilitate earlier diagnosis of this disorder. We present evidence for an overlapping phenotype with the Laurence-Moon syndrome and propose a unifying, descriptive label be adopted (polydactyly-obesity-kidney-eye syndrome). We report an increased prevalence of renal malformations and renal cell carcinoma in the unaffected relatives of BBS patients and suggest that these may be a consequence of heterozygosity for BBS genes. Our findings have important implications for the care of BBS patients and their unaffected relatives.

Adolescent↗

PubMed2000

[Molecular genetics of pigmentary retinopathies: identification of mutations in CHM, RDS, RHO, RPE65, USH2A and XLRS1 genes].

PURPOSE: To evaluate the occurrence and inheritance of various types of pigmentary retinopathy in patients followed at the outpatient clinic in the university hospital, Montpellier, France. To characterize genes and mutations causing these conditions. METHODS: Ophthalmic examination and various visual tests were performed. Mutations were sought from genomic DNA by PCR amplification of exons associated with single-strand conformation analysis and/or direct sequencing. RESULTS: Among 315 patients over an 8-year period, cases of retinitis pigmentosa (63.2%), Usher's syndrome (10.2%), Stargardt's disease (5.4%), choroideremia (3.2%), Leber's congenital amaurosis (3.2%), congenital stationary night blindness (2.9%), cone dystrophy (2.5%), dominant optic atrophy (1.9%), X-linked juvenile retinoschisis (1.6%), Best's disease (1.6%), and others (4.3%) were diagnosed. In retinitis pigmentosa, inheritance could be determined in 54.2% of the cases including dominant autosomic (26.6%), recessive autosomic (22.6%), and X-linked cases (5%) while it could not be confirmed in 45.7% of the cases (simplex cases in the majority). For the 6 examined genes, mutations were found in 22 out of 182 propositus (12.1%). Analysis of phenotype-genotype correlations indicates that in retinitis pigmentosa, RDS is more frequently associated with macular involvement and retinal flecks, RHO with regional disease, and RPE65 with the great severity of the disease with some cases of Leber's congenital amaurosis. CONCLUSIONS: Identification of genes may help in diagnosis and in genetic counseling, especially in simplex cases with retinitis pigmentosa. In this latter condition, molecular diagnosis will be necessary to rationalize future treatments.

Adaptor Proteins, Signal Transducing↗

PubMed2004

[Molecular genetic study of congenital stationary night blindness].

PURPOSE: Molecular genetic study was conducted on patients with fundus albipunctatus, incomplete and complete types of congenital stationary night blindness(CSNB), and Oguchi disease. RESULTS: Mutations in the RDH5 gene were identified in all 10 patients with typical clinical features of fundus albipunctatus. Mutations in the gene were also detected in patients with fundus albipunctatus associated with cone dystrophy, and it was supposed that mutations of the gene cause progressive retinal dystrophy as well as fundus albipunctatus. Mutations in the CACNA1F gene were identified in all 15 patients with typical clinical features of incomplete CSNB. We found that some cases with incomplete CSNB were associated with retinal degeneration or optic atrophy with progressive impairment of vision. We detected mutations in the NYX gene in about half of the cases with complete CSNB. Molecular examination was useful to determine the exact hereditary pattern. We examined the arrestin gene and the rhodopsin kinase gene in 5 unrelated patients with Oguchi disease, and found arrestin gene mutations in 4 of them and a rhodopsin kinase gene mutation in the fifth patient. CONCLUSIONS: We confirmed that fundus albipunctatus, incomplete CSNB, complete CSNB, and Oguchi disease were associated with mutations in the RDH5, CACNA1F, NYX, arrestin or rhodopsin kinase genes, respectively, in Japanese patients. Molecular analysis made it possible to diagnose patients with atypical phenotype and to obtain novel information about phenotypic variation.

Adolescent↗

PubMed2006

Electrophysiological findings in persons with nyctalopia.

INTRODUCTION: Ophthalmologists are occasionally confronted with an individual presenting with nyctalopia (i.e., a relatively greater difficulty seeing at night). When there is no accompanying abnormality seen in the fundus, visual electrophysiology becomes useful as an objective means of assessing rod (scotopic) photoreceptor function or pathway defects. MATERIALS AND METHODS: A retrospective study was performed on 50 consecutive patients, aged less than 40 years, with seemingly normal fundi and good vision [visual acuity (VA) >6/12] presenting to the Visual Electrodiagnostic Unit, Singapore National Eye Centre, for the investigation of nyctalopia over a 2-year period. Subjective scotopic threshold sensitivity (STS) and objective full-field electroretinogram (ERG) were performed. Persons with abnormal test results were identified. RESULTS: Normal ERG scotopic responses were obtained in 74% of subjects. There was no significant difference in age, refraction and STS levels between subjects with abnormal and normal ERG. In the group with abnormal scotopic ERG responses, 9 were identified to have nonspecific rod dysfunction, 2 had rod-cone dystrophies and 2 had ERG changes suggestive of congenital stationary night blindness (CSNB). CONCLUSION: A large number of subjects presenting with nyctalopia had normal ERG findings. We can only assume that in these patients, no significant rod pathway dysfunction exists and that optical (e.g., night or instrument myopia) and psychological aetiologies should be considered. The fact that an abnormal result occurs in 26%, however, suggests that ncytalopia should be evaluated with electrophysiolgoical testing even when the fundi appear normal.

Adult↗

PubMed1991

[Relation of visual acuity of test field luminance in glare sensitivity of various origin].

Intolerance to bright light is a nonspecific ophthalmological symptom, originating either in disturbances of the optic apparatus of the eye or caused by functional disturbances of the neuronal network of the retina. Disturbances in brightness and darkness adaptation can often cause considerable decrease in visual acuity, which is not evident in the standardized tests that measure photophobia in conjunction with visual function. If the test field is very bright and the patient has photophobia, the visual acuity is often reduced considerably. The relationship between visual acuity and luminance of the test field was determined in glare--sensitive patients using a relatively simple method and a large range of luminances (0.1-30,000 cd/m2). In contrast to previously used methods, visual acuity was determined in a range where neuronal mechanism can be expected to be responsible for adaptation to brightness. We found disturbances in the relationship between visual acuity and luminance in several diseases, and it was especially pronounced in cone dystrophies. Affections of the optic nerve and opacities of the optic media usually did not cause a marked decrease in visual acuity at high luminances. As a supplemental investigation to mesoptometry and nyctometry, the method described here primarily permits types of photophobia to be determined that are not caused by stray light. The dynamic nature of neuronal adaptation processes determined by this test has therefore considerable influence on visual acuity.

Adaptation, Ocular↗

PubMed1989

Bull's-eye maculopathy and negative electroretinogram.

The authors studied four patients with a bull's-eye maculopathy and otherwise normal fundus. A single-flash electroretinogram (ERG) with an intense white light stimulus in the dark showed a normal a-wave but reduced b-wave amplitude (negative ERG). Other findings common to all four patients were initially normal visual acuity, subsequent progressive decrease in visual acuity, mild to moderate deficiency of color vision, normal peripheral visual field, relatively well preserved cone ERG, normal 30-Hz flicker ERG, normal EOG, near emmetropia and selective involvement in males. Cone dystrophy, retinitis pigmentosa, congenital retinoschisis, congenital stationary night blindness, and Batten's disease were excluded. The correlation between this disease and benign concentric annular macular dystrophy is discussed.

Adult↗

PubMed1984

Rapid off-response and retinal receptor diseases.

A method was described to record the electroretinogram (ERG) in response to off- and on-stimuli, using Ganzfeld light stimulation. The rapid off-response representing the cone response was recorded with the off-stimuli with the light-dark ratio of 10:1 to maintain a constant photopic condition of 1.6 X 10(3) trolands (Zero log unit). The amplitude of the rapid off-response to completely extinguishing the background light was Vo and the amplitude elicited by intermediate intensities of off-stimuli was V. Vo-V was thought to represent the state of the receptor hyperpolarization, and it was correlated with the stimulus intensity (I) by Log (Vo-V) = nLog I + C; n averaged 0.84 +/- 0.15 in 12 normal subjects, and C was a constant. The scotopic b-wave was recorded by on-stimuli with the light-dark ratio of 1:100 and with the intensity less than -2.0 log units. The cone threshold was calculated using the criterion amplitude of the rapid off-response of 10 microvolts. The rod threshold was likewise computed with the criterion amplitude of the scotopic b-wave of 50 microvolts. The cone and rod sensitivities were determined in 5 patients with progressive cone (-rod) dystrophy and in 8 patients with central pigmentary retinal dystrophy. The cone sensitivity was markedly reduced in the former and the rod sensitivity was highly affected in the latter conditions. Separate evaluations of the cone and rod functions by the present technique will be clinically useful.

Adult↗

PubMed1981

Contrast sensitivity and retinal disease.

A new and practical test for contrast sensitivity (Arden gratings) was evaluated in retinal diseases and found to be a more sensitive indicator of dysfunction than Snellen acuity. Most patients with acuity of 20/30 or better (e.g., with retinitis pigmentosa or toxic retinopathy) showed diminished sensitivity to finely spaced gratings, while patients with poor acuity (e.g., with cone dystrophy) showed normal sensitivity to coarsely spaced gratings. Grating tests may allow earlier diagnosis and more precise follow-up of retinal disease, but their specificity for particular disorders remains to be established.

Adult↗

PubMedDate not supplied

[Genetics of congenital color vision defects. II. Rare types of color blindness].

Between the rare types of colour blindness, the known best are defects of blue colour vision, which are called tritanopia or trinanomaly (tritanomalous trichromacy). Their incidence is 1 in 500 and they are inherited in autosomal dominant way with incomplete penetrance. The basis of them are mutations of the short (blue) wavelength sensitive visual pigment gene. The gene has been mapped on the chromosome 7 and has already been cloned and sequenced. However, the loci heterogeneity should not be excluded in that condition. Another rare type of colour blindness in blue cone monochromacy. It is based on the cone sensitivity to short (blue) wavelength only. The condition is inherited in X-linked recessive way and it is known, that it can be caused by 2 different mechanisms. The first one--two-step pathway--consists of green cone pigment gene deletion, and point mutation of red cone pigment gene. The second one--one-step pathway--arose by deletion of regulatory sequence of both genes of visual pigments, mapped on the X chromosome. Different types of total and partial achromatopsia are also described. The best known ones are: rod monochromacy, which is inherited in autosomal recessive way and consist of rod vision only, and cone dystrophy, usually inherited in X-linked recessive way.

Chromosome Mapping↗

PubMed1995

[Social ophthalmologic aspects of retinitis pigmentosa].

Inherited retinal degenerations cause severe visual handicaps or blindness later in life. In typical rod cone dystrophy (retinitis pigmentosa) there is relevant visual loss in the third decade with implications for the patients' professional life, their mobility and their private life. For this reason, the disease is relevant for the individual patient as well as for society in general. We investigated social issues in 233 retinitis pigmentosa patients: 9.9% are not able to read any more; 40.9% have never had a driver's license and 27.8% quit driving because of a visual handicap. The mean reduction in the capacity for work is 86%; 12.7% are unable to work and therefore receive public financial support; 22.6% are unable to work in their profession; 20.9% are receiving public support because of legal blindness. Against this background it seems to be important that ophthalmologists inform their patients thoroughly about the implications of the disease for their professional and private lives. Doing this, he/she should ask for support from social service professionals.

Activities of Daily Living↗

PubMed1997

Evaluation of the gene encoding the tissue inhibitor of metalloproteinases-3 in various maculopathies.

PURPOSE: Mutations in the gene encoding the tissue inhibitor of metalloproteinases-3 (TIMP3) have been shown previously to cause Sorsby's fundus dystrophy, an autosomal-dominant disorder characterized by extracellular matrix irregularities in Bruch's membrane. To assess the involvement of TIMP3 in a variety of other macular dystrophies, the authors have screened this gene for disease-causing mutations in age-related macular degeneration (AMD), adult vitelliform macular dystrophy (AVMD), central areolar choroidal dystrophy (CACD), syndrome-associated macular dystrophies, cone-rod dystrophy, and a group with unspecified macular degeneration. METHODS: Single-stranded conformational analysis of the entire coding region was performed using the polymerase chain reaction and oligonucleotide primers flanking the five exons of the TIMP3 gene as well as the putative promotor region and a highly conserved fragment of the 3'-untranslated region. The authors analyzed a total of 217 patients, including 143 patients with AMD, 28 patients with AVMD, 21 patients with CACD, and 25 patients with other forms of macular dystrophy. RESULTS: In the 217 patients analyzed, the authors have identified one sequence alteration (a G-to-C base change) in the 5'-untranslated region in a patient with AMD. However, the functional consequences of this mutation are not clear. No other disease-causing mutations were found. The authors have characterized a frequent intragenic polymorphism in exon 3 of the TIMP3 gene (heterozygosity = 0.57) that will be useful for genetic linkage or allele sharing analyses or both. CONCLUSIONS: The authors' results suggest that TIMP3 is not a major factor in the cause of AMD, AVMD, and CACD. Thus far, Sorsby's fundus dystrophy appears to be the only phenotype known to be associated with mutations in TIMP3.

Aged↗

PubMed1997

Localization of CSNBX (CSNB4) between the retinitis pigmentosa loci RP2 and RP3 on proximal Xp.

PURPOSE: Proximal Xp harbors many inherited retinal disorders, including retinitis pigmentosa (RP) and congenital stationary night blindness, both of which display genetic heterogeneity. X-linked congenital stationary night blindness (CSNBX) is a nonprogressive disease causing night blindness and reduced visual acuity. Distinct genetic loci have been reported for CSNBX at Xp21.1, which is potentially allelic with the RP3 gene, and at Xp11.23, which is potentially allelic with the RP2 gene. The study to identify the RP2 gene led to an extended study of families with potentially allelic diseases that include CSNBX. METHODS: Haplotype analysis of a family diagnosed with CSNBX was performed with 17 polymorphic markers on proximal Xp covering previously identified loci for CSNBX and XLRP. Two-point and multipoint lod scores were calculated. RESULTS: Informative recombinations in this family define a locus for CSNBX (CSNB4) with flanking markers DXS556 and DXS8080 on Xp11.4 to Xp11.3, an interval spanning approximately 5 to 6 cM. A maximum lod score of 3.2 was calculated for the locus order DXS556-1 cM-(CSNB4-DXS993)-2 cM-DXS1201. CONCLUSIONS: The results describe a new localization for CSNBX (CSNB4) between the RP2 and RP3 loci on proximal Xp. CSNB4 is not allelic with any previously reported XLRP loci; however, the interval overlaps the locus reported to contain the cone dystrophy (COD1) gene, and both diseases are nonrecombinant with DXS993. Because mutations in the RPGR gene to date account for disease in only a small proportion of RP3 families, the possibility that this new locus (CSNB4) also segregates with an as yet unidentified XLRP locus cannot be excluded.

Chromosome Mapping↗

PubMed2000

Autosomal dominant cone-rod retinal dystrophy (CORD6) from heterozygous mutation of GUCY2D, which encodes retinal guanylate cyclase.

OBJECTIVE: To describe the clinical features of autosomal dominant cone-rod retinal dystrophy (CRD) in a British family mapping to chromosome 17p12-p13 (CORD6), with a heterozygous mutation (Glu837Asp/ Arg838Ser) of GUCY2D. DESIGN: A prospective, clinical family survey. PATIENTS: Ten affected members of a family with autosomal dominant CRD. METHODS: Full clinical examinations were undertaken. Selected affected family members underwent electrophysiologic evaluation, scotopic static perimetry, dark adaptometry, and color vision assessment. MAIN OUTCOME MEASURES: Clinical appearance and electroretinographic responses. RESULTS: Typical clinical and electroretinographic features of childhood-onset CRD were recorded. In addition, moderate myopia and pendular nystagmus were seen in affected individuals. Color vision assessment in the youngest affected individual showed no color discrimination on a tritan axis, but retention of significant red-green discrimination. Electronegative electroretinogram responses were seen on electrophysiology in the only young family member examined. CONCLUSIONS: The phenotype associated with GUCY2D CRD is clinically distinct from that associated with other dominant CRD loci. Unusual electroretinographic responses may indicate that this mutation of GUCY2D is associated with early defects in photoreceptor synaptic transmission to second-order neurons.

Adolescent↗

PubMedDate not supplied

Analysis of peripherin/RDS gene for Japanese retinal dystrophies.

We studied 133 Japanese patients with retinal dystrophies to detect peripherin/RDS (retinal degeneration slow) gene defects. The patients analyzed included 52 with autosomal dominant retinitis pigmentosa, 36 with autosomal recessive retinitis pigmentosa, 3 with simplex retinitis pigmentosa, 12 with cone-rod dystrophy, 5 with rod-cone dystrophy, 3 with vitelliform macular dystrophy (Best's disease), 4 with macular dystrophy, 2 with cone dystrophy, 2 with fundus flavimaculatus, 2 with fundus albipunctatus, and 12 with retinitis pigmentosa with macular degeneration as well as 40 unrelated normal persons. Three exons of the peripherin/RDS gene cut into 150-200 base-pair fragments were amplified by polymerase chain reaction and screened by single-strand conformation polymorphism. The DNA fragments with any suspected variations were directly sequenced. Eight point mutations were detected. Among them, two missense mutations at codons 304 and 338 result in an amino acid substitution of glutamine for glutamic acid and aspartic acid for glycine, respectively. However, they were not cosegregated with the diseases, and these mutations were also commonly found in normal controls. For these controls, the proportion of transversion from G to C at codon 304 (GAG-->CAG) and transition from G to A at codon 338 (GGC-->GAC) were 0.192 +/- 0.045 and 0.173 +/- 0.053, respectively. Our results suggest that a peripherin/RDS gene mutation might be rare in Japanese patients.

DNA↗

PubMed2005

Mutation in the gene GUCA1A, encoding guanylate cyclase-activating protein 1, causes cone, cone-rod, and macular dystrophy.

PURPOSE: To determine the underlying molecular genetic basis of a retinal dystrophy identified in a 4-generation family and to examine the phenotype and the degree of intrafamilial variability. DESIGN: Prospective case series. PARTICIPANTS: Six affected individuals from a nonconsanguineous British family. METHODS: Detailed ophthalmologic examination, color fundus photography, autofluorescence imaging, and electrophysiologic assessment were performed. Blood samples were taken for DNA extraction, and mutation screening of GUCA1A, the gene encoding guanylate cyclase-activating protein 1 (GCAP1), was undertaken. RESULTS: All affected subjects complained of mild photophobia and reduced central and color vision. Onset was between the third and fifth decade, with subsequent gradual deterioration of visual acuity and color vision. Visual acuity ranged between 6/9 and counting fingers. Color vision was either absent or markedly reduced along all 3 color axes. A range of macular appearances was seen, varying from mild retinal pigment epithelial disturbance to extensive atrophy. Electrophysiologic testing revealed a range of electrophysiologic abnormalities: isolated cone electroretinography abnormalities, reduced cone and rod responses (with cone loss greater than rod), and isolated macular dysfunction. The 4 coding exons of GUCA1A were screened for mutations in affected and unaffected family members. A single transition, A319G, causing a nonconservative missense substitution, Tyr99Cys, segregated uniquely in all affected subjects. CONCLUSIONS: The Tyr99Cys GUCA1A mutation has been previously shown to cause autosomal dominant progressive cone dystrophy. This is the first report of this mutation also causing both cone-rod dystrophy and isolated macular dysfunction. The phenotypic variation described here exemplifies the intrafamilial heterogeneity of retinal dysfunction that can be observed in persons harboring the same mutation and chromosomal segment.

Adult↗

PubMed1999

Cone and rod dysfunction in the NARP syndrome.

AIMS: Description of the ophthalmic manifestations of the NARP (neuropathy, ataxia, retinitis pigmentosa) syndrome that is associated with a point mutation in position 8993 of the mitochondrial DNA (mtDNA). METHODS: A mother and her two children, all carrying the 8993 mtDNA mutation, were examined. Two had manifestations of the NARP syndrome. A complete ocular and systemic examination was performed on all three patients. RESULTS: The clinical examination, electroretinogram, and visual fields revealed a typical cone-rod dystrophy in the son, and a typical cone dystrophy in the daughter. The mother had no ocular manifestations of the disease. CONCLUSIONS: NARP is a recently described, maternally inherited mitochondrial syndrome in which a retinal dystrophy, among other abnormalities, is related to a mutation of the mtDNA at nucleotide 8993. This study demonstrates the great variability of the ocular manifestations in the NARP syndrome. It also indicates that the retinal dystrophy in at least some NARP patients affects primarily the cones.

Adolescent↗

PubMedDate not supplied

[Mixed photoreceptor dystrophy. Apropos of two cases].

Two observations of cone-rod dystrophy are reported. It's about two brothers. The transmission way is not defined. The extinction of the scotopic ERG and the final threshold of the rod in dark adaptation shows the rod participation in this disease. In this case, the characteristics of the progressive cone dystrophy (photophobia, achromatopsia, visual capacity loss, respect of the peripheric visual field, alteration of the photopic ERG) are seen. Fundus examination and angiography are discussed and reported to the vitreofluorometry.

Adolescent↗