Autosomal dominant Stargardt-like macular dystrophy: identification of a new family with a mutation in the ELOVL4 gene

PURPOSE: To describe the clinical features and identify the mutation responsible for an autosomal dominant macular degeneration occurring in a four-generation family. METHODS: Family members underwent clinical examination and genealogical characterization. Mutation screening of the ELOVL4 gene was performed. RESULTS: Patients reported visual loss occurring at a mean age of 20 years. Fundus examination revealed varying degrees of central macular atrophy with or without flecks in all affected individuals. DNA sequence analysis showed a 5-bp deletion in exon 6 of the ELOVL4 gene, confirming the diagnosis of autosomal dominant Stargardt-like macular dystrophy. Genealogical analysis showed that this family represents a new affected branch of a previously described 12-generation family (31 branches) with this disorder. CONCLUSIONS: We characterized a new branch of a family with autosomal dominant Stargardt-like macular dystrophy. Identification of the disease-causing gene allows for improved genetic counseling of affected individuals.     

Autosomal dominant Stargardt-like macular dystrophy segregating in a large Canadian family

BACKGROUND: Inherited macular dystrophies account for a major fraction of the cases of retinal degenerative disease that lead to permanent blindness. We describe the clinical and genetic findings in a Canadian family with a form of macular dystrophy resembling autosomal dominant Stargardt-like macular dystrophy. METHODS: Standard ophthalmologic examinations were performed in members of a single five-generation Alberta family. Tests of visual acuity and colour vision, fundus photography, fluorescein angiography and electroretinography were performed in 15 affected people. Blood was collected from 24 family members, and DNA was extracted for genotyping. Genetic linkage analysis was performed using polymorphic short tandem repeat microsatellite markers located on chromosome 6q, a region containing loci for several macular disorders. RESULTS: Affected family members display clinical characteristics resembling autosomal dominant Stargardt-like macular dystrophy, previously assigned to chromosome 6q (STGD3). Linkage analysis generated a peak lod score of 5.50 at an estimated recombination fraction of 0.00 for marker locus D6S300. INTERPRETATION: The family described has an autosomal dominant macular dystrophy that resembles Stargardt-like macular dystrophy. The disease locus for this family maps to an interval on chromosome 6q that overlaps that for STGD3 and other retinal dystrophy loci. These findings provide further evidence that human chromosome 6q represents a "hot spot" for retinal disorders.     

Spider dystrophy as an ocular manifestation of myotonic dystrophy

BackgroundMyotonic dystrophy is the most common adult-onset muscular dystrophy. It is an autosomal dominant inherited neuromuscular disease that is characterized by myotonia, muscle weakness, and atrophy. It affects multiple systems including skeletal muscular, gastrointestinal, cardiac, respiratory, central nervous, endocrine, and ocular. Ocular manifestations of myotonic dystrophy include cataract, ocular muscle changes, hypotony, and retinal pigmentary changes in the periphery or in the macula (known as pigment pattern dystrophy). This report presents and discusses the case of a pigmented pattern dystrophy known as spider dystrophy as an ocular manifestation of myotonic dystrophy.Case ReportA 44-year-old man with myotonic dystrophy presented to the eye clinic for routine examination. Ocular history included previous bilateral cataract surgery and mild bilateral ptosis for the last “few years.” Dilated fundus examination was remarkable for bilateral macular pigmentary changes in an irregular “spider”-shaped pattern. The patient was asymptomatic without decrease in vision or Amsler grid defects. Optical coherence tomography was normal. A retinal consult concurred with the diagnosis of spider dystrophy. Photo documentation was obtained, and the patient is being monitored annually.ConclusionPigmented pattern dystrophies, including spider dystrophy, have been associated with myotonic dystrophy. They are set apart from other retinal dystrophies because they rarely affect visual acuity, and the majority of patients are asymptomatic. Progression may lead to reduced vision and in rare cases choroidal neovascularization. Annual dilated examinations, photo documentation, optical coherence tomography, and home Amsler grid monitoring are recommended for follow-up care.     

Reticular macular dystrophy and Steinert disease

We studied the macular lesions of 14 patients with myotonic dystrophy. 4 of them presented signs of reticula dystrophy of the macular pigmentary epithelium. We searched the association with other ocular modifications.     

Hereditary macular dystrophy. A clinical and genetic study of two specific forms.

Four families with nine members affected with autosomal recessive macular dystrophy (Stargardt's Disease) and one family with six members affected with autosomal dominant macular dystrophy have been examined. Age of onset, rate of visual deterioration, fundus appearance, electroretinography and dark adaptometry have been compared in the various families. Some differences, particularly in the rate of visual deterioration and in the fundus appearance were noted between the recessive and dominant forms. Despite these differences in the clinical and related features, the genetic implications are of greater importance to the affected individuals. Genetic counselling which provides recurrence risks of the disorder in the affected individuals' siblings and children should be included in the assessment of patients with these forms of hereditary ocular disease.     

Antibodies against human retinal proteins in serum from patients with cone dystrophy.

Eleven patients with cone dystrophy were examined for serum antibodies against human retinal proteins. Sera were screened by immunoblotting methods using human retinal proteins as antigens. Three cases from different families showed a distinct band at the molecular weight of 14 kDa; the hereditary pattern of these seropositive cases was autosomal recessive or sporadic with parental consanguinity. The serum antibodies were negative in the other sporadic or autosomal dominant cases of cone dystrophy with similar clinical features, in cases of various ocular diseases including macular dystrophies, and in healthy adults. No sera tested showed any specific antibodies against proteins from the human optic nerve or spinal cord.     

Autosomal dominant cone-rod dystrophy with negative electroretinogram.

AIMS--The negative electroretinogram (ERG) is observed in many hereditary retinal disorders. However, no reports have described a negative ERG in a family with autosomal dominant cone-rod dystrophy. A Japanese family with autosomal dominant cone-rod dystrophy with negative ERG is described. METHOD--Members of a Japanese family with autosomal dominant cone-rod dystrophy were examined and evaluated with Goldmann and Humphrey perimetry, bright flash ERG with an intense white stimulus, rod, cone, and flicker ERGs, and fluorescein angiography. Molecular analysis of the rhodopsin and peripherin/RDS genes in the patients was also performed. RESULTS--A 45-year-old Japanese man (proband) presented with decreased visual acuity. His fundi revealed bull's eye maculopathy and his single flash bright ERG showed a negative configuration. Negative ERG responses also were found in his father, who had macular degeneration, and one of the proband's three children who showed no fundus changes. No irregularities were found in their rhodopsin or peripherin/RDS genes. CONCLUSION--The condition of this family is believed to represent a previously undescribed autosomal dominant cone-rod dystrophy.     

Autosomal dominant macular dystrophy in a large Canadian family

BACKGROUND: We studied a large Canadian family (178 total family members) spanning seven generations with autosomal dominant macular dystrophy. We performed a study to identify the gene mutation responsible for the disease in the family. METHODS: Participating family members were evaluated clinically. Genetic linkage, genotyping, mutation screening and an extensive genealogic investigation were performed. RESULTS: The common clinical findings in affected family members included progressive early- to mid-onset visual loss and extensive areas of central chorioretinal atrophy. Two-point linkage analysis indicated linkage to chromosome 6p. Direct DNA sequencing showed a C/T transition in codon 172 of the retinal degeneration slow (RDS) gene creating an amino acid change to Arg172Trp. Haplotype analysis of affected family members using microsatellite markers distributed around the RDS gene locus revealed that the markers were not conserved when compared to members of British families with the Arg172Trp mutation. Genealogic studies indicated the family immigrated to Canada from Ireland in 1843. INTERPRETATION: A newly identified large family with autosomal dominant macular dystrophy is described. The phenotypic appearance of the fundus is similar to that of previously described patients with an Arg172Trp mutation in the RDS gene. Haplotype analysis of markers spanning the disease locus identified a new founder for this mutation. The identification of the disease-causing gene in this family allows for better genetic counselling for patients with this condition and provides a basis to distinguish clinically similar types of macular dystrophy based on the clinical phenotype.     

Ocular hypotonia and retinal injuries in Steinert disease. Angiographic aspects

The authors study ocular complications, mainly retinal, in three patients with myotonic dystrophy. The association of cataract, ocular hypotony, reticular or butterfly-shaped dystrophy of the macular pigmentary epithelium was observed in all cases. A bibliographical study regarding retinal lesions: clinical aspects (macular lesions and peripheral retinopathy), retinal functions (visual acuity, color sense, dark adaptation, electrophysiological examinations), histopathological aspects with proliferation of peripheral pigmentary epithelium, retinal and choroidal fibrohyalinosis. The authors report vitreous and retinal modifications (disc, macula, retinal vessels, peripheral retinopathy), evolutive aspects, electrophysiological anomalies in order to understand at best Steinert's ocular lesions.     

Autosomal recessive cerebellar ataxia with bull's-eye macular dystrophy

PURPOSE: In 1980, we published in the American Journal of Ophthalmology two siblings with hereditary ataxia and atrophic maculopathy. The report is cited in the literature as autosomal dominant cerebellar ataxia with retinal degeneration. The purpose of the present study is to document the progression of the neurodegenerative disorder and to review the diagnosis. DESIGN: Observational case report. METHODS: Twenty years after the original publication, the 52-year-old male patient had new ocular and neurologic examinations, fluorescein angiography, molecular genetic analysis, and biochemical testing. RESULTS: Fluorescein angiography showed marked progression of the macular dystrophy to a bull's-eye configuration. Genetic analysis of the patient did not show CAG trinucleotide repeat expansion in the various spinocerebellar ataxia genes. This excludes the diagnosis of autosomal dominant cerebellar ataxia with macular degeneration (ADCA type II) with mutation of the spinocerebellar ataxia 7 gene. Major causes of autosomal recessive cerebellar ataxia with retinal degeneration, including Friedreich ataxia and congenital disorders of glycosylation, were also excluded. CONCLUSION: The two patients, previously published in the American Journal of Ophthalmology by Eerola and coworkers, did not suffer from presently recognized disorders with cerebellar ataxia and retinal degeneration. The Eerola syndrome probably represents a separate neurodegenerative entity characterized by autosomal recessive cerebellar ataxia and progressive macular dystrophy with a bull's-eye pattern.     

Myotonic dystrophy Curschmann-Steinert

BACKGROUND: Myotonic dystrophy Curschmann-Steinert is a multisystemic disorder inherited as an autosomal dominant trait. Characteristic clinical findings are muscular weakness and distal atrophy of the extremities, myotonia and myopathic facies. Ophthalmological symptoms may include cataract, ptosis and intraocular hypotension. Cardiac conduction defects, endocrine disturbances, respiratory insufficiency and gastrointestinal affection appear quite often in the course of the disease. Because of the great diversity of symptoms and the variable clinical presentation the disease may be overlooked. CASE REPORT: In January 2006, a 58-year-old woman presented with progressive vision loss on both eyes, lumbal discomfort and pain, as well as a gradual weakness of the right leg. Ophthalmological evaluation revealed a star-shaped posterior subcapsular cataract, subtle ptosis on both eyes and weakness of the eyelid closure. Morphologically we observed a lack of facial expression manifesting as a myopathic facies and a moderate cachexia. Neurological findings included muscle weakness and atrophy in the extremities as well as of the sternocleidomastoid and temporal muscles a slight dysarthrophony and gait disturbance. Furthermore, an increase of the creatine kinase levels in the blood was detected. Electromyography (EMG) showed signs of a myopathic process in the proximal muscles of the lower extremities (right and left vastus medialis muscle). Although no typical myotonic discharges were recorded in the EMG, molecular testing confirmed the clinical suspicion of myotonic dystrophy type Curschmann-Steinert. CONCLUSIONS: The combination of a myotonic muscle disorder with ophthalmological, and probably cardiac, abdominal and pulmonary symptoms, especially respiratory insufficiency and sleep apnoea should lead to the suspicion of a myotonic dystrophy. Due to the high incidence of ocular manifestations, especially of the typical myotonic cataract, an ophthalmological investigation is essential for a straightforward diagnostic procedure.     

Macular coloboma in siblings affected by different phenotypes of retinitis pigmentosa

Purpose To report the clinical association between macular coloboma (early-onset macular dystrophies/atrophic changes) and different phenotypes of retinitis pigmentosa (RP).Methods Three young-adult siblings, two males and one female, were retrospectively studied. These patients underwent two complete ophthalmologic examinations (27-month follow-up), including orthoptic evaluation, colour vision test, visual field, corneal topography, electronystagmography, fluorescein angiography, and electroretinography. Eye check, automated visual field test, and complete electroretinographic study were also conducted on other asymptomatic members of the same family.Results All symptomatic siblings were affected by manifest congenital nystagmus, poor visual acuity, and progressive visual field impairment in both eyes, bilaterally presenting macular coloboma associated with three different RP patterns: classic RP; mild dystrophy of the retinal pigment epithelium, associated with subnormal electroretinographic findings (subclinical form of RP); and sector RP. The ophthalmologic reports regarding their deceased father documented that he had suffered from the same alterations of ocular movements and visual performances diagnosing, in both eyes, extensive atrophic changes of the macular area completely surrounded by pigmented bone spicules (RP-type tapeto-retinal dystrophy). The other investigated relatives did not show any specific and/or significant ocular disorder.Conclusions In these three adult members of the same family, the concomitance between macular coloboma and different intrafamilial RP phenotypes is described. This association represents an autosomal dominant clinical entity, hitherto observed only in non familial sporadic cases.Eye (2004) 18, 421-428. doi:10.1038/sj.eye.6700689     

Bilateral optic nerve atrophy in myotonic dystrophy

PURPOSE: To document a case of bilateral optic atrophy in a patient with myotonic dystrophy. Myotonic dystrophy is an autosomal dominant disorder, genetically resulting from an expansion of an unstable CTG repeat in the 3'-untranslated region of a protein kinase gene (DMPK) on chromosome 19q13.3. METHODS: Case report, clinical examination, fundus photographs, visual fields, visual evoked potentials, electroretinograms, and genetic studies of a 56-year-old woman clinically diagnosed with myotonic dystrophy. RESULTS: The patient experienced decreased vision consisting of light perception with the right eye and 20/25 with the left. Fundus examination showed bilateral pallor of the optic disks. Intraocular pressure was normal. Visual field testing, visual evoked potentials, and electroretinogram were abnormal. A pathologic CTG expansion in the myotonic dystrophy gene was found. CONCLUSIONS: In a patient with myotonic dystrophy, confirmed with genetic molecular diagnosis, bilateral optic atrophy was present. Optic atrophy should be considered a possible complication of myotonic dystrophy.     

Autosomal dominant pattern dystrophy: identification of a novel splice site mutation in the peripherin/RDS gene

PURPOSE: To describe the clinical features of and identify the mutation responsible for an autosomal dominant pattern dystrophy occurring in a three-generation family. METHODS: Five affected family members underwent clinical examination and additional testing including intravenous fluorescein angiography where indicated. Mutation screening of the peripherin/RDS gene was performed. RESULTS: Visual acuity ranged from 20/20 to counting fingers. All patients who reported vision loss noted the onset after the age of 40 years. Predominantly perifoveal, discrete, retinal pigment epithelial changes were present in all patients. Two patients had extensive peripheral yellowish flecks, and one had an atrophic macular scar. Mutation screening of the complete peripherin/RDS coding sequence and exon/intron boundaries revealed a novel splice site mutation. CONCLUSION: A three-generation family with an autosomal dominant pattern dystrophy arising from a previously unreported splice site mutation in the RDS gene is described.     

An autosomal dominant bull's-eye macular dystrophy (MCDR2) that maps to the short arm of chromosome 4

PURPOSE: To describe the phenotype of an autosomal dominant macular dystrophy and identify the chromosomal locus. METHODS: Eleven members of a five-generation, nonconsanguineous British family were examined clinically and also underwent automated perimetry, electrodiagnostic testing, fundus fluorescein angiography, and fundus autofluorescence imaging. Blood samples were taken for DNA extraction and linkage analysis was performed. RESULTS: The phenotype is characterized by bull's-eye macular dystrophy first evident in the first or second decade of life. There is mild visual impairment, central scotomata, and electrophysiological testing indicates that most affected individuals have disease confined to the central retina but older subjects have more widespread rod and cone abnormalities, demonstrated by flash ERG. Genetic linkage analysis established linkage to chromosome 4 at p15.2-16.3 with a maximum lod score of 3.03 at a recombination fraction of 0.00 for marker D4S391. The locus for this autosomal dominant macular dystrophy lies between flanking markers D4S3023 and D4S3022, and overlaps the Stargardt 4 locus. CONCLUSIONS: A new locus was identified for a bull's-eye macular dystrophy on the short arm of chromosome 4.     

Novel complex GUCY2D mutation in Japanese family with cone-rod dystrophy

PURPOSE: All mutations in the retinal guanylate cyclase gene (GUCY2D) that causes autosomal dominant cone-rod dystrophy (CORD) are associated with an amino acid substitution in codon 838. A novel heterozygous complex missense mutation of I915T and G917R in the GUCY2D gene was found in a Japanese family with autosomal dominant CORD. The clinical features associated with this mutation were described. METHODS: Blood samples were collected from 27 patients with cone-rod or cone dystrophies and from 11 patients with macular dystrophy. Genomic DNA was extracted from peripheral leukocytes. All 18 coding exons of the GUCY2D gene were directly sequenced. The PCR product carrying a novel mutation was subcloned, and each allele was sequenced. A complete ophthalmologic examination was performed in members of the family with the novel mutation. RESULTS: A novel heterozygous complex missense mutation of T2817C and G2822C that would predict I915T and G917R amino acid substitutions, respectively, was found in an autosomal dominant CORD family. The two nucleotide changes were located on the same allele, and segregated with the disease. Two other known missense mutations of R838H and R838C were found in two other CORD families. The clinical phenotype associated with the novel mutation was similar to that with the Arg838 mutations. CONCLUSIONS: A heterozygous complex mutation of I915T and G917R in the GUCY2D gene caused autosomal dominant CORD, indicating that a heterozygous mutation that does not include a codon 838 substitution can lead to this ocular phenotype.     

Atypical vitelliform macular dystrophy in a 5-generation family.

Five generations of a family with autosomal dominant atypical vitelliform macular dystrophy (A-VMD) were studied. This dystrophy is similar to autosomal dominant Best's vitelliform dystrophy (B-VMD) but clinically more closely resembles sporadic pseudovitelliform macular degeneration (P-VMD). Of the family members who were 14 years or older 43 (24 females and 19 males) of the 101 at risk (43%) were affected. Vision varied from 20/20 to 20/200. Field defects and tritan colour defects were invariably present only when vision was less than or equal to 20/200, but these defects were sometimes present when vision was good. The electrooculographic studies (LP/DT ratios) in this family were found to be normal or reduced and did not correlate with visual acuity. Minimal retinal findings consisted of macular or extramacular punctate yellow lesions or both in the retinal pigment epithelium, which were hypofluorescent by angiography, and retinal pigment epithelial defects in the temporal nerve fibre bundle, which were hyperfluorescent by angiography. Fluorescein angiographic changes were invariably present when retinal lesions were noted, and this was the most reliable test in identifying genotypically affected family members with minimal phenotypic expression.     

The spectrum of ocular phenotypes caused by mutations in the BEST1 gene

Bestrophin-1 is an integral membrane protein, encoded by the BEST1 gene, which is located in the basolateral membrane of the retinal pigment epithelium. The bestrophin-1 protein forms a Ca²⁺ activated Cl^? channel and is involved in the regulation of voltage-dependent Ca²⁺ channels. In addition, bestrophin-1 appears to play a role in ocular development. Over 120 different human BEST1 mutations have been described to date, associated with a broad range of ocular phenotypes. The purpose of this review is to describe this spectrum of phenotypes, which includes Best vitelliform macular dystrophy and adult-onset foveomacular vitelliform dystrophy, autosomal dominant vitreoretinochoroidopathy, the MRCS (microcornea, rod-cone dystrophy, cataract, posterior staphyloma) syndrome, and autosomal recessive bestrophinopathy. The genotype–phenotype correlations that are observed in association with BEST1 mutations are discussed. In addition, in vitro studies and animal models that clarify the pathophysiological mechanisms are reviewed.     

Autosomal dominant Stargardt-like macular dystrophy

Autosomal dominant Stargardt-like macular dystrophy is one of the early onset macular dystrophies. It is characterized clinically in its early stages by visual loss and by the presence of atrophic macular changes with or without the presence of yellowish flecks. It is an important retinal dystrophy to study, not only because it has implications in the care and treatment of patients with the condition, but because it also provides important information regarding retinal function. Review of the literature suggests that many of the reported families are linked to chromosome 6q. Genetic and genealogical evidence suggests that these families have descended from a common ancestor or founder. The recent identification of a disease-causing gene that is involved in fatty acid metabolism may have implications in the study of the more common age-related macular degeneration. We review the recent clinical, genetic, and genealogical aspects of autosomal dominant Stargardt-like macular dystrophy.     

Cone dystrophy associated with Alport syndrome

BACKGROUND: Alport's syndrome is a hereditary disease with renal, cochlear, and ocular involvement. We report a patient with Alport's syndrome who exhibited morphologic macular changes similar to cone dystrophy. HISTORY AND SIGNS: A 46-year-old man was evaluated for peculiar macular changes, which have caused a significant decrease in visual acuity over the last years. His general history was remarkable for the presence of sensorineural hearing impairment since infancy as well as end stage renal failure followed by renal transplantation. The ophthalmological findings in this patient included circumscribed macular lesions consisting of atrophy of the retinal pigment epithelium and bilateral anterior lenticonus. CONCLUSION: Alport's syndrome is a characteristic prototype of a genetic basement membrane disease with ocular, renal, and cochlear involvement. Common ocular findings are the dot-and-fleck retinopathy and the anterior lenticonus. In contrary to the anterior lenticonus retinal changes are rarely associated with visual impairment. An association with a macular lesion similar to the cone dystrophy has only infrequently been reported.