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PubMed1988

Normal alpha-L-fucosidase and other lysosomal enzyme activities in progressive cone dystrophy.

We conducted a cross-sectional study of 24 patients with cone dystrophy to investigate a possible link between this disease and deficient activity of alpha-L-fucosidase. We studied patients with several forms of cone dystrophy, including six with similar clinical characteristics to two patients previously reported to be alpha-L-fucosidase deficient. Activities for alpha-L-fucosidase and several other lysosomal enzymes (beta-D-glucuronidase, beta-D-hexosaminidase (A + B), and alpha-D-mannosidase) were determined in serum and leukocytes. None of our patients with cone dystrophy were deficient in alpha-L-fucosidase or any other lysosomal enzyme investigated. No relationship was found between alpha-L-fucosidase deficiency and any type of cone dystrophy studied.

Adolescent↗
PubMed1976

Progressive cone dystrophies.

Patients with progressive generalized cone dystrophy often present nystagmus (or strabism) and complain of photophobia, decrease in visual acuity or disturbances in colour perception. The most classic fundus abnormality is the bull's eye maculopathy or a pallor of the optic disc. Minimal macular changes are sometimes seen, which may progress to a bull's eye type of macular degeneration. The photopic ERG is always very affected, whereas at first the scotopic ERG seems normal. Progressive deterioration of the visual functions is accompanied by increasing fundus lesions and rod involvement, as suggested by the modifications of the dark adaptation curve and the scotopic ERG. However, the progression of typical generalized cone dysfunction is very slow. On the contrary, in some cases of so-called Stargardt's disease with peripheral participation, a very rapid progression has been observed. In such cases a normal ERG does not necessarily mean that the disease will remain localized to the macular area. No definite prognosis can be made on one single ERG. In 3 cases with sector pigmentary retinopathy the photopic ERG was more affected than the scotopic ERG. However, these cases are probably primary cone-rod dystrophies. Although there is no electrophysiological control, our clinical impression is that the evolution, if possible, is very slow.

Adolescent↗
PubMed1991

Electroretinogram in cone dystrophy.

Electroretinograms (ERGs) in 10 cases of cone dystrophy were studied with special respect to log(bp/bs) that represents the log of photopic ERG amplitude divided by scotopic ERG amplitude. Photopic ERGs were either greatly diminished or nonrecordable, and scotopic ERGs showed either normal or reduced amplitudes. All cases had a low value of log(bp/bs), less than the lower normal limit, indicating significantly greater impairment in cone function than in rod function. These results have proved log(bp/bs) to be helpful in confirming the diagnosis of cone dystrophy especially in cases with recordable photopic ERG and reduced scotopic ERG. Among other ERG parameters, the photopic ERG b-wave implicit time that was determined with averaging and digital amplification of the responses in 4 cases showed prolongation in 3 cases while normal in one case. Oscillatory potentials were nonrecordable or barely recordable in all cases.

Adult↗
PubMed1992

[Colored light stimuli in ERG for differential diagnosis of cone dystrophies].

We recorded electroretinograms (ERG) with white and color stimuli in normal persons and four patients with cone dystrophies. Kodak Wratten-filters in blue, blue-green, green, yellow and red were used for the color flashes. ERGs to all color stimuli were recorded at dark and light adapted conditions with different stimulus intensities, to 30 Hz flicker stimulation and with special filtering for oscillatory potentials. Selective blue cone-responses were obtained using strong blue flashes at a yellow background. Patients with cone dystrophies showed slightly to moderately reduced responses at dark adaptation to blue, blue-green, green and yellow stimuli. Red stimuli elicited only small responses with a markedly delayed b-wave implicit time. The light adapted recordings, flicker responses and oscillatory potentials were reduced to all color stimuli. However, differences between patients with cone dystrophies could be detected concerning the responses to red and green. In two patients the responses were reduced to the same degree to all color stimuli. Another patient had very small responses and no oscillatory potentials to red, but his responses were only moderately reduced to green. A patient with combined red-green cone and rod dystrophy had a blue cone hypersensitivity. Responses to blue and blue-green were large at all stimulus conditions, but responses to all other stimuli were much smaller. The blue cone ERG showed a prominent blue cone response. ERG recording to colored stimuli allows a separation of retinal dysfunction in patients with cone dystrophies.

Adult↗
PubMed1994

[Differential diagnosis of cone dystrophies].

Electrophysiological and psychophysical findings recorded in 70 patients with three hereditary diseases of the cone system,--blue cone monochromatism, cone-rod dystrophy and selective cone dystrophy--were compared. Blue cone monochromatism is distinguished from the other two diseases by a reduction of visual acuity since childhood, without progression and with a sex-linked mode of inheritance. In addition, nystagmus is generally observed only in the time shortly after birth and the green and red cones are found to be missing on spectral sensitivity measurements. Cone-rod dystrophy can be distinguished from the blue cone monochromatism by a reduction in visual acuity later in life with progression of the symptoms. Spectral sensitivity measurements reveal reduced function of all three cones in cone-rod dystrophy and a single cone mechanism in selective cone dystrophy. Moreover, in cone-rod dystrophy the ERG reveals a reduction in the amplitudes of the photopic system and often mild involvement of the scotopic part. Measurement of the spectral sensitivity and the ERG can thus help in the diagnosis of these three hereditary diseases.

Color Perception↗
PubMed1994

DNA carrier detection in X-linked progressive cone dystrophy.

X-linked progressive cone dystrophy (XLPCD) is characterized by progressive macular atrophy, abnormal colour vision, reduced cone responses in ERG, and reduced visual acuity. XLPCD may be genetically heterogeneous. Therefore, carrier detections by DNA analysis may only be carried out in those families in which the position of the gene locus can be clearly established. Here, we describe the first DNA carrier detections in XLPCD.

DNA↗
PubMedDate not supplied

X-linked cone dystrophy.

A description is given of a new family with X-linked cone dystrophy. A survey is also given of the findings in X-linked cone dystrophy. When an eye specialist sees a male patient with myopia and reduced visual acuity, the cause of which is not clear from the fundus picture, an X-linked cone dystrophy should be considered. Electrophysiological examination, combined with detailed testing of colour vision, can provide an explanation of the poor vision which satisfies both the patient and the ophthalmologist.

Adult↗
PubMed2001

A novel Gly35Ser mutation in the RDH5 gene in a Japanese family with fundus albipunctatus associated with cone dystrophy.

OBJECTIVE: To assess the clinical and genetic characteristics of a Japanese family with fundus albipunctatus with progressive cone dystrophy associated with a mutation in the RDH5 gene. DESIGN: Case report with clinical findings and results of fluorescein angiography, electroretinograms, kinetic visual field testing, dark adaptometry, and DNA analysis. SETTING: University medical center. PATIENTS: We studied the ocular findings in 6 members of a Japanese family with fundus albipunctatus with cone dystrophy and a guanine-to-adenine transversion at the first nucleotide in codon 35 of the RDH5 gene. The mutation resulted in a substitution of serine for glycine in amino acid 35 (Gly35Ser) of the RDH5 gene. RESULTS: Characteristic features included poor night vision, white dots in the retina, cone dystrophy, and a mottled appearance of the retinal pigment epithelium. Electroretinograms showed greater impairment of the rod-mediated responses than the cone-mediated responses. After 3 hours of dark adaptation, the a and b waves and scotopic b waves recovered. CONCLUSIONS: Although the mutation of the RDH5 gene has been known as a causative gene of fundus albipunctatus, the Gly35Ser mutation in the RDH5 gene may be related to the pathogenesis of progressive retinal degeneration. This phenomenon may provide evidence of gene phenotype caused by a mutation in the RDH5 gene. CLINICAL RELEVANCE: The Gly35Ser mutation causes fundus albipunctatus with cone dystrophy. This finding provides evidence that some kinds of mutations in the RDH5 gene are related, in part at least, to the pathogenesis of progressive retinal degeneration.

Alcohol Oxidoreductases↗
PubMed1993

Cone dystrophies with negative photopic electroretinogram.

A scotopic electroretinogram with an a-wave amplitude larger than the b-wave amplitude traditionally is termed 'negative'. Six male patients with negative photopic electroretinograms were examined; three of them suffered from progressive cone dystrophy, in which negative electroretinograms are unusual. Another patient without symptoms was the brother of a patient with cone dystrophy. These patients are compared with others who characteristically have negative electroretinograms-one patient with incomplete congenital stationary night blindness and another with X linked congenital retinoschisis. Differential diagnosis between these unusual cases of cone dystrophies and X linked retinoschisis or congenital stationary night blindness was possible with funduscopy, adaptometry, and evaluation of progression, but not with the electroretinogram. Inner retinal defects may occur in cone dystrophies as indicated by the negative electroretinogram. The waveform variations between our patients may be due to different inner retinal defects. The findings in two brothers indicate that cone dystrophy and inner retinal defects may be inherited separately.

Adolescent↗
PubMed2003

Cone dystrophy phenotype associated with a frameshift mutation (M280fsX291) in the alpha-subunit of cone specific transducin (GNAT2).

AIM: To describe the phenotype of a three generation consanguineous Pakistani family containing six individuals with autosomal recessive cone dystrophy caused by mutation in GNAT2. METHODS: Five of the six affected individuals underwent an ophthalmological examination, electrodiagnostic testing, fundus photography, autofluorescence imaging, and detailed psychophysical testing. RESULTS: All five examined patients had a history of nystagmus from infancy, photophobia, defective colour vision, and poor visual acuity. The nystagmus in three of the individuals had lessened with time. Fundus examination revealed an abnormal foveal appearance, without frank atrophy or pigmentation. Electroretinography (ERG) revealed absent ISCEV cone flicker ERGs with some preservation of responses to short wavelength stimulation. Rod ERGs showed no definite abnormality, but maximal (mixed rod-cone) response a-wave amplitudes were mildly subnormal. Rudimentary residual colour vision was detected in three individuals. There is clinical evidence of progressive visual acuity reduction in two older individuals. CONCLUSION: Mutation in the alpha-subunit of cone specific transducin (GNAT2) is characterised by an infantile onset cone dystrophy. Some affected individuals may show deterioration of visual acuity with time.

Adult↗
PubMed2006

Tinted contact lenses as an alternative management for photophobia in stationary cone dystrophies in children.

BACKGROUND: Intense photophobia is a debilitating symptom of the stationary cone dystrophies. The dark-tinted glasses with side-shields and floppy hats used to manage this are very conspicuous and can cause marked psychological morbidity to the children and their families. We assess the use of tinted contact lenses as an alternative management for the photophobia. METHODS: Three children, aged 5 to 13, with cone dystrophies, all with markedly reduced visual acuity, color vision, and profound photophobia were fitted with Lunelle ES70 Solaire 70% brown contact lenses. The child's parents completed two Children's Visual Function Questionnaires, the first pertaining to the period when the child wore tinted glasses; the second pertaining to the period of tinted contact lens wear. RESULTS: Subjectively, two of the children and their parents described a striking improvement in their quality of life, with improved confidence, interactions with other children, and cessation of name-calling and bullying. The Children's Visual Function Questionnaires gave objective evidence for this improvement in one child and was not significantly different in the other. The third child was reluctant to wear the contact lenses despite her parents' active encouragement. CONCLUSION: Tinted contact lenses offer an alternative management of the photophobia associated with stationary cone dystrophies in children. Marked improvements in their quality of life were observed in this case series.

Adolescent↗
PubMed2005

Autosomal dominant cone dystrophy caused by a novel mutation in the GCAP1 gene (GUCA1A).

PURPOSE: To describe the clinical features and genetic analysis of a family with an autosomal dominant cone dystrophy (adCD). METHODS: Selected members of a family with an autosomal dominant cone dystrophy underwent ophthalmic evaluation. Blood samples were obtained, genomic DNA was isolated, and genomic fragments were amplified by PCR. Linkage to locus D6S1017 was established. DHPLC mutational analysis and direct sequencing were used to identify a mutation in GUCA1A, the gene encoding the guanylate cyclase activating protein 1 (GCAP1). RESULTS: Of 24 individuals who are at risk of the disease in a five generation family, 11 members were affected. Clinical presentations included photophobia, color vision defects, central acuity loss, and legal blindness with advanced age. The disease phenotype was observed in the second and third decades of life and segregated in an autosomal dominant fashion. An electroretinogram performed on one proband revealed profoundly subnormal and prolonged photopic and flicker responses, but preserved scotopic ERGs, consistent with a cone dystrophy. Mutational analysis and direct sequencing revealed a C451T transition in GUCA1A, corresponding to a novel L151F mutation in GCAP1. Like the E155G mutation, this mutation occurs in the EF4 hand domain, a region of GCAP1 critical in conferring calcium sensitivity to the protein. The leucine at this position is highly conserved among vertebrate guanylate cyclase activating proteins. CONCLUSIONS: A novel L151F missense mutation in the EF4 high affinity Ca2+ binding site of GCAP1 is linked to adCD in a large pedigree. The cone dystrophy in this family shares clinical and electrophysiologic characteristics with other previously described adCD caused by mutations in GUCA1A.

Adult↗
PubMed2005

Progressive cone dystrophy with deutan genotype and phenotype.

PURPOSE: To study the electroretinographic signals originating in the long-wavelength-sensitive (L) and middle-wavelength-sensitive (M) cone pathways by means of large-field and multifocal cone type-specific electroretinograms (ERGs) in a patient with progressive cone dystrophy. METHODS: A 65-year-old male patient with colour vision disturbances (age at onset 10 years), loss of visual acuity (14 years), and central visual field defects (40 years) was investigated. Large-field flicker-ERG responses to stimuli that exclusively modulated the L-cones or the M-cones, or the two simultaneously (both in-phase and in counter-phase), were measured. Short-wavelength-sensitive (S) cones were not modulated. Multifocal ERGs (mfERGs) were also recorded, with a pattern-reversing display that modulated only the L- or the M-cones at equal cone contrasts and average quantal catches. Genetic analysis of L- and M-pigment genes was performed on genomic DNA isolated from peripheral venous blood. RESULTS: The patient showed a normal rod-driven ERG but reduced cone-driven electroretinographic amplitudes with normal implicit times in the International Society for Clinical Electrophysiology of Vision (ISCEV) standard ERG. The large-field flicker-ERG responses to pure L-cone modulation were significantly above noise level but were substantially reduced in comparison with both normal trichromatic subjects and (otherwise normal) deuteranopes. The L-cone driven electroretinographic implicit times and phases were within normal limits. The M-cone driven electroretinographic responses were not detectable. A model fit of all the L- and M-cone driven flicker-ERG data revealed that the responses were exclusively driven by the L-cones. Consistently, the cone type-specific mfERGs showed severely reduced but detectable responses to L-cone-isolating stimuli. The M-cone driven multifocal-ERG responses were undistinguishable from noise. The L- and M-pigment gene array consisted of only a single L-pigment gene. The complete coding sequence of this gene was determined and showed no abnormality. CONCLUSIONS: This patient exhibits a coincidence of progressive cone dystrophy and deuteranopia. The molecular genetic data of the L/M-pigment gene array is consistent with the deutan phenotype. It cannot be excluded that the rearrangement of the X-chromosome pigment gene array is responsible for the cone dystrophy in this patient. It is, however, suggested that the dichromacy and the cone dystrophy have different and independent genetic origins.

Aged↗
PubMed2004

Progressive cone dystrophy associated with mutation in CNGB3.

PURPOSE: To determine the molecular basis for phenotypic variability in a three-generation consanguineous family containing a single individual with complete achromatopsia and three individuals with progressive cone dystrophy. METHODS: Four affected individuals underwent ophthalmic examination, electrophysiological assessment, color fundus photography, and psychophysical testing. Blood samples were obtained for DNA extraction and mutation screening of the cone-specific cGMP-gated (CNG) channel protein gene CNGB3 was undertaken. RESULTS: The clinical findings in one family member were consistent with a diagnosis of complete achromatopsia, with nystagmus, photophobia, and poor visual acuity from early infancy and complete color-blindness, normal fundi, and absent cone responses with normal rod responses on electroretinography (ERG). Mutation analysis revealed her to be homozygous for the common CNGB3 achromatopsia mutation, 1148delC (Thr383fs). In contrast, the three other symptomatic individuals in the family had findings consistent with progressive cone dystrophy. Their visual problems began later in childhood (ranging from 3 to 14 years of age) and there was evidence of progressive deterioration in cone function. All three had a marked tritanopic color vision defect and fundoscopy revealed bilateral macular atrophy. Electrophysiological testing of these three subjects demonstrated clear evidence of progressive deterioration of cone responses over time; rod responses were normal. All three individuals with this progressive phenotype were found to be compound heterozygotes for the 1148delC (Thr383fs) frameshift mutation and a novel Arg403Gln missense mutation in CNGB3. CONCLUSIONS: Mutations in CNGB3, which have been shown to cause achromatopsia, are now shown to be associated with autosomal recessive progressive cone dystrophy. In this study, a novel Arg403Gln mutation was identified, located in the middle of the pore domain of the cone CNG cation channel beta-subunit, which when associated with the nonsense mutation Thr383fs, resulted in progressive cone dystrophy.

Adult↗
PubMedDate not supplied

Curvilinear pigmentary lesions in a rod-cone dystrophy.

PURPOSE: To report a peculiar curvilinear pigmentary lesion in the peripheral fundus in a rod-cone dystrophy. METHODS: Observational case report. Fundus examination of a 57-year-old woman who was known to have a generalized rod-cone dystrophy since she was 8 years old. RESULTS: The peripheral fundus examination revealed a curvilinear lesion which resembles a well-known finding associated with a presumed ocular histoplasmosis syndrome or multifocal choroiditis. CONCLUSIONS: The differential diagnosis of a peculiar curvilinear pigmentary lesion in the peripheral fundus may be expanded to include a generalized rod-cone dystrophy.

Choroiditis↗
PubMed2004

Young monozygotic twin sisters with fundus albipunctatus and cone dystrophy.

OBJECTIVE: To describe young monozygotic twin sisters with fundus albipunctatus (a type of autosomal recessive stationary night blindness caused by mutations of the 11-cis retinol dehydrogenase gene [RDH5]) associated with cone dystrophy, previously reported in elderly men. METHODS: Ophthalmologic examinations were performed, and the RDH5 gene was analyzed by direct genomic sequencing. RESULTS: Twin 23-year-old sisters with high myopic refractive errors of approximately -13 diopters were diagnosed as having fundus albipunctatus. Their photopic electroretinographic responses were markedly reduced, and cone dystrophy was diagnosed. One twin had macular degeneration with reduced best-corrected visual acuity, while the other twin had normal maculae with good visual acuity. A compound heterozygous mutation, Val132Met and Arg280His, in the RDH5 gene was found in both sisters. CONCLUSIONS: Cone dystrophy can be present in patients with fundus albipunctatus, not only elderly men but also young women. The clinical severity differed between monozygotic twins with fundus albipunctatus and cone dystrophy.Clinical Relevance The patient's sex is not critical for the presence of cone dystrophy in patients with fundus albipunctatus. The discordant findings in the twins indicate that factors other than genetics influenced the phenotype.

Adult↗
PubMed1990

Color matching and foveal densitometry in patients and carriers of an X-linked progressive cone dystrophy.

We describe a family with an as yet undescribed form of X-linked progressive cone dystrophy in a five-generation pedigree, from which we report here the results of 17 male patients and 31 obligate and 13 possible female carriers. The affected males showed the characteristic picture of cone dystrophy. Foveal cone photopigment density was impaired (judged from anomaloscope settings and foveal densitometry), even at an early stage of the disease. The carriers showed no fundus abnormalities, except occasional changes due to myopia. The anomaloscope demonstrated mild pseudoprotanomaly in 27 of 31 obligate carriers and in six of 13 possible carriers. Foveal densitometry findings performed in 11 carriers always agreed with the anomaloscope findings. We conclude that the findings of pseudoprotanomaly and abnormal density differences in females of this family were the only ocular abnormalities and thus are indicative of the carrier state.

Adult↗