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Cerebrospinal fluid specimens (CSF) from 59 patients with optic neuritis and from 59 age-matched neurological control patients were studied. The patients with optic neuritis showed significantly higher CSF IgG concentrations and a higher frequency of abnormal CSF electrophoresis as compared with the control specimens. Elevated relative IgG values (expressed as percentage of CSF total protein concentration) were noticed in 42%, abnormal electrophoresis in 41%, pleocytosis in 26% and increased total protein concentrations in 29% of CSF specimens from patients with optic neuritis. Thirty patients with an unknown cause of optic neuritis and without any neurological symptoms other than optic neuritis, showed increased relative IgG in 40%, abnormal electrophoresis in 31%, pleocytosis in 33% and increased total protein concentration in 27% of CSF specimens. A reduced serum/CSF albumin ratio was noticed in high frequency in patients with optic neuritis indicating possible blood brain barrier damage. There were, however, 13 patients with optic neuritis and two from the control group with normal serum/CSF albumin ratio but reduced serum/CSF IgG ratio. This finding supports the presumption that part of CSF IgG is produced within the central nervous system (CNS).

A family with hereditary, neuropathologically confirmed olivopontocerebellar atrophy (OPCA) associated with macular degeneration is described. The mode of inheritance was autosomal dominant. The first symptom was insidious, progressive visual loss caused by macular degeneration. Another early sign was slow saccades. Some years after the visual symptoms, gradually progressing cerebellar dysfunction and pyramidal signs developed. Computed tomography of the brain indicated cerebellar and pontine atrophy. Finally the patients were blind, due to a severe chorioretinal atrophy, and disabled because af motor dysfunction. The present study, together with a review of other reported families with OPCA associated with macular degeneration, suggests that this disorder is a specific and clinically recognizable subtype of OPCA.

The visual evoked potentials (VEPs) and neuro-ophthalmological examinations of 134 patients were compared. The VEPs were abnormal in 95 % of the eyes with optic neuritis. Defective color vision was found in 99 %, visual field defects in 88 %, decreased vision in 66 % and an afferent pupillary defect in 55 %. 29 patients with optic neuritis were followed up with repeated tests. VEPs and color vision recovered more slowly than visual acuity and visual field. Abnormal VEPs were observed in 68 % of 50 MS patients. An analysis of symptomatic and asymptomatic eyes showed that testing of color vision, visual field and red-free ophthalmoscopy were equally as useful diagnostic tools as VEPs. 4 (8 %) of the MS patients had abnormal VEPs despite a normal neuro-ophthalmological examination; 94 % of MS patients with symptoms and 47 % of MS patients without visual symptoms had abnormal VEPs. VEPs were pathological in 59 % of 24 patients with traumatic or compressive optic nerve diseases or optic atrophies of unknown etiology. The neuro-ophthalmological examination was more sensitive than VEPs in the diagnosis of these disorders. A neuro-ophthalmological examination is in most cases sufficient to diagnose optic nerve lesions. VEPs are of diagnostic aid especially in mild optic nerve lesions.

A neurological and ophthalmological re-examination has been carried out of 116 patients with optic neuritis (ON), who were treated at the eye clinic of the Central Hospital of Turku University during the years 1950–1969. The follow-up period of patients varied from 3 to 22 years (average 10.2 years). Fifty-eight (50.0 per cent) had probable MS (Multiple Sclerosis) and 18 (15.5 per cent) possible MS. Thirty-two (42.1 per cent) earlier undiagnosed cases of MS were found in this material. In most of these cases the patients' neurological symptoms were so mild that they had not consulted a neurologist. This indicates that MS is a more common disease than the selective studies based on patients collected from the hospital records in a neurological clinic would suppose. ON with some cause other than MS was observed in 15 (13.0 per cent) patients, among whom were many cases with a neurological disease other than MS. The etiology of ON remained unknown in 25 (21.6 per cent) patients. Many of these patients had some very mild neurological symptoms, but a diagnosis of MS, based on criteria of the Schumacher committee, could not be made. After a longer follow-up period, even these cases can perhaps be classified as suffering from MS. Neurological and ophthalmological findings in re-examined patients are described and compared with previous reports. Six families with occurrence of MS within the family, and two with Leber's hereditary optic atrophy are reported. Our studies indicate that ON must be considered as an important sign of a disease of the central nervous system and not only as an isolated eye disease.

Contains fulltext : 52562.pdf (Publisher’s version ) (Closed access) Leber hereditary optic neuropathy (LHON) is due primarily to one of three common point mutations of mitochondrial DNA (mtDNA), but the incomplete penetrance implicates additional genetic or environmental factors in the pathophysiology of the disorder. Both the 11778G-->A and 14484T-->C LHON mutations are preferentially found on a specific mtDNA genetic background, but 3460G-->A is not. However, there is no clear evidence that any background influences clinical penetrance in any of these mutations. By studying 3,613 subjects from 159 LHON-affected pedigrees, we show that the risk of visual failure is greater when the 11778G-->A or 14484T-->C mutations are present in specific subgroups of haplogroup J (J2 for 11778G-->A and J1 for 14484T-->C) and when the 3460G-->A mutation is present in haplogroup K. By contrast, the risk of visual failure is significantly less when 11778G-->A occurs in haplogroup H. Substitutions on MTCYB provide an explanation for these findings, which demonstrate that common genetic variants have a marked effect on the expression of an ostensibly monogenic mtDNA disorder.

We have performed an entire-population-based survey of the epidemiology and penetrance of Leber hereditary optic neuropathy (LHON) in Finland - a country that is among the best-studied genetic isolates in the world. During our long-term clinical follow-up period since 1970, we have so far identified 36 LHON families in Finland, comprised of almost 1000 family members. Counting the unaffected family members has been possible thanks to accessible genealogical records, and this has improved the accuracy of our penetrance figures by minimizing the sample bias. Our results, although confirming some well-known features of LHON, indicate that the overall penetrance of LHON is lower than previously estimated, and that affected females have a higher incidence of affected offspring compared to the unaffected females. The prevalence of LHON in Finland is 1:50 000, and one in 9000 Finns is a carrier of one of the three LHON primary mutations.

Nordic ophthalmologists and vision scientists are active in many fields of eye research. This is most evident at the biannual Nordic Congress of Ophthalmology, most recently held in Malmo in June 2004. The authors here review some of the research in vision and ophthalmology presented at this meeting or published recently by Nordic scientists. This paper does not represent a comprehensive review of all Nordic research in the field, but attempts to give an overview of some of the activities underway in eye research in this part of the world.

Purpose: To assess the clinical picture and molecular genetics of 14 Finnish families with dominant optic atrophy (DOA). Methods: The clinical status of family members was based on the assessment of visual acuity, colour vision, visual fields and optic nerve appearance; 31 individuals were affected, two suspect and 21 unaffected. A total of 30 coding exons and exon− intron boundaries of the OPA1 gene were sequenced in order to detect mutations. Results: Half the patients were diagnosed at the age of ≤ 20 years. Ten out of 20 affected individuals followed up for ≥ 6 years had a progressive disease and 10 had a stable disease. According to WHO criteria, 36% of the affected patients were visually handicapped. Eight OPA1 pathogenic mutations, all but one novel, and 18 neutral polymorphisms were detected. Conclusion: The most sensitive indicators of DOA were optic disc pallor and dyschromatopsia. With molecular genetic analysis, asymptomatic mutation carriers and DOA cases with a mild clinical outcome were ascertained. No mutational hotspot or Finnish major mutation in the OPA1 gene could be demonstrated as most families carried a unique mutation. No obvious genotype− phenotype correlation could be detected. Detailed clinical assessment and exclusion of non-DOA families prior to mutation screening are necessary for obtaining a high mutation detection rate.

Purpose: To demonstrate the importance of mitochondrial DNA (mtDNA) analysis in the diagnosis of Leber hereditary optic neuropathy (LHON) and illustrate the difficulties in genetic counseling of the disease. Participants and methods: Ophthalmological and molecular genetic study of one affected and three unaffected members from a family with heteroplasmic ND1/3460 mtDNA mutation associated with LHON. Results: The proband had variable amounts of mutant mtDNA in all his tissues studied, ranging from 58% in blood to 92% in subcutis. The mother had an extremely low amount of mutant mtDNA in her tissues, except for hair roots, which contained only normal mtDNA. No mutant mtDNA could be detected in the proband's unaffected sister and maternal aunt. Conclusions: Despite her minimal mutation load, the mother of the proband has still transmitted a considerable amount of mutant mtDNA to her son, who is severely affected. Although proband's unaffected sister and maternal aunt had no mutant mtDNA, a theoretical risk that they may transmit the disease to their offspring cannot be excluded.

Hereditary optic neuropathies comprise a group of disorders characterized by optic nerve dysfunction. This paper updates recent genetic literature on dominant optic atrophy and Leber hereditary optic neuropathy, both of which cause optic nerve dysfunction.

Background Eye fundus destruction and type II muscle fiber atrophy in gyrate atrophy of the choroid and retina with hyperornithinaemia (GA) may be mediated by elevated ornithine concentrations which strongly inhibit creatine biosynthesis. This results in deficiency of creatine phosphate (PCr), a key intracellular energy source, as we have demonstrated in skeletal muscle of the patients by 31P magnetic resonance spectroscopy (31P MRS). Materials and methods Possible correction of the relative PCr deficiency by long-term daily exogenous supplementation of creatine or its precursors was investigated in four GA patients receiving creatine and in five patients treated with guanidinoacetic acid-methionine combination. The relative PCr concentration, expressed as PCr/Pi (Pi; inorganic phosphate) or as PCr/ATP ratios, was compared with the values of untreated GA patients, and matched healthy volunteers. Results Muscle PCr/Pi ratios (mean ± SD) of the untreated and creatine supplemented GA patients and controls were 4.9 ± 1.4, 7.9 ± 0.4 and 8.4 ± 1.3. Guanidinoacetate-methionine combination was similarly effective (respective PCr/Pi ratios: 4.9 ± 0.7, 6.3 ± 1.1 and 10.7 ± 2.8). Conclusion Supplementation with creatine or creatine precursors almost normalised low muscle PCr/Pi ratios of patients with GA.

Background In gyrate atrophy of the choroid and retina with hyperornithinaemia (GA), inherited deficiency of ornithine-δ-aminotransferase leads to progressive fundus destruction and atrophy of type II skeletal muscle fibres. Because high ornithine concentrations inhibit creatine biosynthesis, the ensuing deficiency of high-energy creatine phosphate may mediate the pathogenesis. Materials and methods Relative concentrations of inorganic phosphate (Pi), creatine phosphate (PCr) and ATP in resting calf muscle were recorded in 23 GA patients and 33 control subjects using 31P-magnetic resonance spectroscopy (MRS). Eight patients with autosomal recessive retinitis pigmentosa with matched control subjects constituted an additional reference group. Results The PCr/Pi and PCr/ATP ratios (means ± SD) were lower for the GA patients than for healthy control subjects [4.66 ± 0.37 vs. 9.75 ± 2.17 (P

Objective The purpose of the study was to determine the nature and course of ophthalmic abnormalities in long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a recently discovered disorder of mitochondrial fatty acid β-oxidation. Study design The study design was a cohort (case series). Participants A retrospective review of the records of 15 children who had died during their first 2 years was performed. Also performed were a longitudinal reanalysis and cross-sectional clinical examination of four long-term survivors aged 5 to 31 years. Main outcome measures Visual acuity, refraction, visual fields, ophthalmoscopy, fluorescein angiography, biometry, corneal topography, electroretinography (ERG), visual-evoked potentials (VEPs), color vision, and dark adaptation were measured. Results In seven children, ophthalmoscopic findings were within normal limits at 3 days to 13 months of age (median, 4.8 months). In 11 children, a granular retinal pigment epithelium (RPE), with or without pigment clumping in the macula, was seen at 4 months to 5 years of age (median, 9 months). Two long-term survivors, 16 and 31 years of age, eventually had circumscribed atrophy of the choroid, RPE, and retina, which coincided with a posterior staphyloma type 1. They had progressive axial myopia starting at 6 and 12 years of age and later paracentral scotomas leading to poor central vision. They suffered from early difficulty with mesopic vision, glare, and a severe generalized color vision deficiency that started as a tritanomaly. A third survivor was mildly myopic at 5 years of age. All four surviving patients had visually insignificant, flake-like supranuclear opacities in the lens. The ERG initially was normal but deteriorated during the first decade and later was unrecordable. The VEP responses remained fairly normal. Initially, angiography showed no blockade of the choroidal fluorescence because of the thin RPE. Filling of choroidal vessels was delayed, and the choriocapillaris and, later, larger choroidal vessels in the posterior pole became nonperfused. Conclusions In LCHAD deficiency, the fundus is normal at birth (stage 1). Soon, however, pigment dispersion occurs in the RPE (stage 2), followed by circumscribed chorioretinal atrophy, occlusion of choroidal vessels, and deterioration of central vision, often with relative sparing of the peripheral fundus (stage 3). Finally, posterior staphylomas and central scotomas may develop (stage 4). Developmental cataract, progressive myopia, and deterioration of visual fields and color vision are new findings in LCHAD deficiency. The chorioretinopathy and abnormal ERG precede the development of myopia and posterior staphyloma, which, in turn, coincide with the loss of macular vision. The authors postulate that the RPE or choriocapillaris is primarily affected. Awareness of the characteristic ocular features is important because of an opportunity for dietary treatment, genetic counseling, and prenatal diagnosis.

Leber hereditary optic neuropathy (LHON) is a maternally inherited eye disease most commonly caused by mitochondrial DNA (mtDNA) point mutation at position 11778, 3460, or 14484. Approximately 14% of families show heteroplasmy for the pathogenic mutations but little is known about the mutational burden in different tissues of these heteroplasmic individuals. Consequently, estimating the risks of visual loss is difficult. This study presents quantitative mutation analyses of tissues representing all embryonal layers in two families heteroplasmic for the 11778 mutation. These analyses show that a high amount of mutated mtDNA in leukocytes is correlated with a high proportion of mutated mtDNA in other tissues.

Short-chain ubiquinone analogues act as electron acceptors and as inhibitors in the lymphoblast mitochondria of ND1/3460 mutants, which indicates structural changes in the ubiquinone-binding domain of Complex I in this mutant. The ND4/11778 mutant and two secondary ND5 mutants studied are associated with reductions of at least 50, 35 and 30% in the catalytic rate constant, respectively. However, the efficiency of oxidative phosphorylation is unaffected in all these ND mutants. The rate of respiration is only slightly limited by Complex I in lymphoblast mitochondria. Consequently, there is a 30-35% reduction in the electron flow through Complex I compared with that through Complex II, and an increased lactate/pyruvate ratio, in the ND1 and ND4 mutants, but these factors were unaffected in the secondary ND5 mutants. Energy metabolism is thus less severely affected in the secondary mutants than in the primary mutants, which supports the division into these two categories. An increased ubiquinone-10 content in the mitochondrial membrane of all the mutants, and enhanced succinate dehydrogenase and citrate synthase activities in the ND4 mutant, are proposed to be compensatory changes. The efficiency of these changes and the level of kinetic limitation of respiration by Complex I in each tissue are proposed to determine the clinical development of the disease.

Background: Leber hereditary optic neuropathy (LHON) is associated with primary and secondary mutations in mitochondrial DNA. Clinical studies suggest that there is a wide spectrum of clinical expression. Methods: Fifty-three affected and 131 unaffected maternal relatives from 21 pedigrees with LHON were studied neuro-ophthalmologically and followed over a period of 14 years. Mitochondrial DNA analysis was performed on their blood specimens. Results: Thirty-two affected (60%) individuals from ten families harbored the 11778 mutation and ten individuals (19%) from three families harbored the 3460 mutation. No confirmed primary mutation was detected in 11 (21 %) affected individuals from eight families. The visual outcome was better in families with the 3460 mutation than in those with the 11778 mutation. Secondary mutations did not affect the penetrance or the visual outcome. Fifteen patients had a favorable outcome; seven of whom had subclinical disease, two had slowly progressive LHON with a favorable visual outcome, and six had classic LHON with spontaneous recovery. In seven patients, the onset of the disease had been in childhood. These patients had a more favorable prognosis than the adults. Results of eye examinations of asymptomatic maternal relatives showed subdinically affected individuals. Conclusions: In addition to classic LHON, the disease can manifest itself in three different atypical forms: subclinical disease, slowly progressive LHON with a favorable visual outcome, and LHON with the classic acute stage but spontaneous visual recovery. The current study suggests that the ophthalmologic findings and outcome in LHON are independent of secondary mutations.

Previous studies suggest that Leber's hereditary optic neuropathy (LHON) may be a systemic disorder with manifestations in organs other than the optic nerves. To evaluate nervous system involvement 38 men and eight women with LHON were re-examined. The patients were divided into three groups according to mtDNA analysis--namely, patients with the 11778 or with the 3460 mutation and patients without these primary mutations. Fifty nine per cent of patients had neurological abnormalities but there was no significant difference between the three groups. Movement disorders were the most common finding; nine patients had constant postural tremor, one chronic motor tic disorder, and one parkinsonism with dystonia. Four patients had peripheral neuropathy with no other evident cause. Two patients had a multiple sclerosis-like syndrome; in both patients MRI showed changes in the periventricular white matter. Thoracic kyphosis occurred in seven patients, five of whom had the 3460 mutation. In one patient the 3460 mutation was associated with involvement of the brain stem. It is suggested that various movement disorders, multiple sclerosis-like illness, and deformities of the vertebral column may associate pathogenetically with LHON.

We have applied time-resolved fluorometry (TRF) to construct a DNA hybridization assay for the diagnosis of Leber hereditary optic neuroretinopathy (LHON). A rapid and reliable detection of the most prevalent mitochondrial DNA (mtDNA) point mutation associated with LHON is demonstrated. In addition, the TRF-method can be used in the quantification of heteroplasmy, a phenomenon commonly present in mtDNA mutations. The assay includes PCR amplification of a fragment encompassing the mutation site followed by hybridization reactions with allele-specific europium (Eu)-labelled oligonucleotide probes. A time-resolved fluorometer is used to measure the bound label. The TRF assay was succesfully used to demonstrate the ND4/11778 mutation in patient samples. For quantification of heteroplasmy, synthetic target oligonucleotide mixtures with known ratios of wild-type and mutated sequences were used as standards to control the hybridization step. The assay allowed the detection of heteroplasmy ranging from 5 to 95%. This was also shown in a family with several heteroplasmic members. © 1994 Wiley-Liss, Inc.

Mitochondrial DNA (mtDNA) mutations are a major cause of human disease. A large number of different molecular defects ultimately compromise oxidative phosphorylation, but it is not clear why the same biochemical defect can cause diverse clinical phenotypes. There is emerging evidence that nuclear genes modulate the phenotype of primary mtDNA disorders. Here, we define an X-chromosomal haplotype that interacts with specific MTND mutations to cause visual failure in the most common mtDNA disease, Leber hereditary optic neuropathy. This effect is independent of the mtDNA genetic background and explains the variable penetrance and sex bias that characterizes this disorder.

To assess the clinical picture and molecular genetics of 14 Finnish families with dominant optic atrophy (DOA).The clinical status of family members was based on the assessment of visual acuity, colour vision, visual fields and optic nerve appearance; 31 individuals were affected, two suspect and 21 unaffected. A total of 30 coding exons and exon- intron boundaries of the OPA1 gene were sequenced in order to detect mutations.Half the patients were diagnosed at the age ofor = 20 years. Ten out of 20 affected individuals followed up foror = 6 years had a progressive disease and 10 had a stable disease. According to WHO criteria, 36% of the affected patients were visually handicapped. Eight OPA1 pathogenic mutations, all but one novel, and 18 neutral polymorphisms were detected.The most sensitive indicators of DOA were optic disc pallor and dyschromatopsia. With molecular genetic analysis, asymptomatic mutation carriers and DOA cases with a mild clinical outcome were ascertained. No mutational hotspot or Finnish major mutation in the OPA1 gene could be demonstrated as most families carried a unique mutation. No obvious genotype- phenotype correlation could be detected. Detailed clinical assessment and exclusion of non-DOA families prior to mutation screening are necessary for obtaining a high mutation detection rate.

To determine the ophthalmologic findings, especially the nature of retinal vascular changes, and their clinical significance in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a disease that causes migraine, recurrent strokes, and finally subcortical vascular dementia.Cross-sectional study.Thirty-eight CADASIL patients (19 to 61 years old; 20 in a prestroke group, 15 in a stroke group, and 3 in a dementia group), all with the R133C NOTCH3 mutation and including one homozygous patient, underwent a detailed ophthalmologic examination.Common cardiovascular risk factors were evaluated. Ophthalmologic examination included best-corrected visual acuity, anterior- and posterior-segment biomicroscopy, and measurement of intraocular pressure. In 33 patients and 16 healthy controls (20-64 years old), retinal fundus photographs were taken. Diameters of all arterioles and venules located in the area from 0.5 to 1.0 disc diameters from the optic disc margin were measured with a computer-based program and arteriole-to-venule (A/V) ratios were calculated from digitized photographs.General arterial narrowing and arteriovenous nickings were common. Straightening of the retinal arterioles and a marked wall reflex (n = 6) occurred. The A/V ratio of CADASIL patients was significantly (P0.001) lower than that of controls. One patient had one retinal microinfarct and hemorrhages. The homozygous patient had a chorioretinal scar as a sign of circulatory deficiency. Anterior-segment changes included mild iris atrophy (n = 5) and various degrees of lens opacities. Visual acuity was normal in all but 2 patients, who had cataract and amblyopia.The generalized arteriopathy of CADASIL causes a wide variety of changes in retinal arterioles but only minimal functional disturbances. These findings are consistent with alterations in arterioles in the cerebral cortex with which the retina and its arterioles are analogous, but contrast with the severe damage of cerebral white matter arterioles.

Leber hereditary optic neuropathy (LHON) is an ocular disease associated with mutations in the mitochondrial DNA (mtDNA). The level of heteroplasmy in the mtDNA mutations ND4/11778 and ND1/3460 was followed over a period of 4-12 years in blood samples taken from nine members of four heteroplasmic LHON families. In addition, hair follicle and urinary tract epithelium samples of one individual were studied. The quantification of heteroplasmy was performed using the solid-phase minisequencing method. Only minor and random shifts in the heteroplasmy levels were observed over time, but there were no systematic changes towards an increasing or decreasing proportion of either LHON mutant in the individuals. This indicates that there is no selection for either mtDNA genotype but the segregation of the wild-type mtDNAs and those carrying LHON mutations is a stochastic process governed by random genetic drift. In this respect, LHON mutations seem to behave like neutral polymorphisms.

To demonstrate the importance of mitochondrial DNA (mtDNA) analysis in the diagnosis of Leber hereditary optic neuropathy (LHON) and illustrate the difficulties in genetic counseling of the disease.Ophthalmological and molecular genetic study of one affected and three unaffected members from a family with heteroplasmic ND1/3460 mtDNA mutation associated with LHON.The proband had variable amounts of mutant mtDNA in all his tissues studied, ranging from 58% in blood to 92% in subcutis. The mother had an extremely low amount of mutant mtDNA in her tissues, except for hair roots, which contained only normal mtDNA. No mutant mtDNA could be detected in the proband's unaffected sister and maternal aunt.Despite her minimal mutation load, the mother of the proband has still transmitted a considerable amount of mutant mtDNA to her son, who is severely affected. Although proband's unaffected sister and maternal aunt had no mutant mtDNA, a theoretical risk that they may transmit the disease to their offspring cannot be excluded.

Objective/purpose To investigate clinical variation in a genetically homogenous group of subjects with gyrate atrophy of choroid and retina with hyperornithinemia (GA). The group was made up of homozygotes and compound heterozygotes for mutation L402P in the ornithine aminotransferase (OAT) gene. Design Cross-sectional study. Participants Thirty-five Finnish subjects (18 men) with GA with a mean age of 33 years (range, 5–74 years) carrying the Finnish founder mutation L402P. Methods All subjects were examined between 1993 and 1995. The analysis was composed of, in addition to careful clinical evaluation, studies of visual fields with Goldmann perimeter, photographing of the eye fundi, and corneal electroretinography (ERG) recordings. Main outcome measures The changes in eye fundi, visual acuity, cataract changes in the lens, visual field constriction, and ERG responses were determined. Results Myopia, early cataracts, and highly abnormal ERG were typical for the GA subjects. The changes progressed rather uniformly with age. However, visual acuity, funduscopic findings, and visual fields showed great phenotypic variation. Despite the great interindividual variation, both eyes of each subject were always similarly affected. Conclusions This study of 35 subjects with GA carrying a single mutation shows that the ophthalmologic symptoms and findings vary widely. The data also reveal that GA subjects are already affected by severe visual impairment in young adulthood. However, the diagnosis is often made very late.

Objective: To determine whether there is a causal link between vigabatrin treatment and concentric visual field defects and to evaluate the prevalence of these visual field constrictions. Background: While the GABAergic antiepileptic drug (AED) vigabatrin was being clinically developed, only rare cases (less than 1:1000) of symptomatic visual field constriction and retinal disorders were reported. During 1997 to 1998, concentric visual field constrictions were described in case reports of mostly drug-resistant epilepsy patients receiving vigabatrin concurrently with other AEDs. Methods: Ophthalmologic tests including Goldmann perimetry were performed on 32 adult patients on long-term successful vigabatrin monotherapy (treatment duration 29 to 119 months) and on 18 patients on carbamazepine monotherapy (treatment duration 32 to 108 months). Eighteen healthy adults served as controls. Results: None of the patients complained about vision problems when asked to participate into the study. Thirteen out of the 32 (40%) epilepsy patients treated with vigabatrin monotherapy had concentrically constricted visual fields (9% severely, 31% mildly constricted), whereas none of the carbamazepine monotherapy patients or normal controls presented with a visual field defect (chi-square test, p = 0.0001). The extents of the visual fields were significantly constricted in vigabatrin group as compared with the visual fields of the patients in carbamazepine group or healthy controls (analysis of variance, Scheffe F-test, significant at 99%). Conclusions: The use of vigabatrin seems to increase the risk of a unique and specific pattern of bilateral, mainly asymptomatic visual field constriction. This risk should be considered when using vigabatrin. Visual field testing should also be performed before treatment and during routine follow-up for patients on vigabatrin.

Purpose: In the spring of 1994, the post-referral waiting time for glaucoma patients at our institution was approximately 7 months. In an attempt to evaluate and possibly reduce this waiting time we compared the referral criteria to the actual treatment requirements of 472 patients admitted for glaucoma in 1995. Results: 175 patients were referred as glaucoma suspects, 134 as chronic simple glaucoma, and 123 as capsular glaucoma. In addition, 40 patients were referred as other types of glaucoma. Elevated IOP was the main criterion for referral in 133 (76%) of glaucoma suspects. The diagnosis of glaucoma could not, however, be confirmed in 54 (31%) glaucoma suspects. 93 (69%) patients with simple open angle glaucoma and 103 (84%) patients with capsular glaucoma were also referred because of IOP ≥ 22 mmHg. Maximally tolerated medication was not used by 44% of open angle glaucoma patients at time of referral. Conclusion: The clinical follow-up of glaucoma patients and glaucoma suspects should primarily take place at an ophthalmologist's office and the new effective glaucoma drugs and laser treatments should also be more actively in use. The cooperation between the referring ophthalmologists and the university clinic should be improved. Hospitalisation turned out to be unnecessary because, with a few exceptions, all procedures could have been performed on an out-patient basis, which is a general practice in most glaucoma clinics today. The university clinic should focus only on those patients who need special evaluation or surgical treatment.

A lowered efficiency of oxidative phosphorylation was recently found in a Leber hereditary optic neuropathy (LHON) proband carrying a mutation in the mtDNA gene for subunit 6 of the membrane-bound F0 segment of the F1F0-ATP synthase [9]. This phenotype was transferred to cytoplasmic hybrid cells together with the mutation, proving its functional significance. Increasing the respiratory rate in the mitochondria from this mutant raised the ATP/2e− ratio back to normal values. A different mutation in the same mtDNA gene has been found in patients with the NARP syndrome [10]. Although the ATP/2e− ratio is also decreased in this mutant, in this case an increase in the respiratory rate could not compensate for it. Whilst both mutations affect subunit 6 of the proton-translocating F0 segment, the LHON mutation induces a proton leak whereas the NARP mutation blocks proton translocation. Hence, the latter will have much more destructive metabolic consequences in agreement with the large clinical differences between the two diseases.

International audience; Expanded CAG repeat sequences have been identified in the coding region of genes mutated in several neurodegenerative disorders, including spinocerebellar ataxia type 1 and Machado-Joseph disease. In all disorders described to date the CAG expansion codes for an elongated polyglutamine chain. An increased polyglutamine chain size leads to a more severe disease, thus correlating with the genetic anticipation seen in repeat expansion disorders. Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant spinocerebellar ataxia with anticipation and a progressive degeneration of the cerebellar cortex. Using repeat expansion detection (RED), a method in which a thermostable ligase is used to detect repeat expansions directly from genomic DNA, we have analyzed 8 SCA7 families for the presence of CAG repeat expansions. RED products of 150-240 bp were found in all affected individuals and found to cosegregate with the disease (P < 0.000001, n = 66), indicating strongly that a CAG expansion is the cause of SCA7. On the basis of a previously established correlation between RED product sizes and actual repeat sizes in Machado-Joseph disease, we were able to estimate the average expansion size in SCA7 to be 64 CAG copies.

About two-thirds of patients with Leber hereditary optic neuroretinopathy (LHON) harbor mutations in mitochondrial DNA at positions 11778 (ND4) or 3460 (ND1). Thus, the clinical diagnosis of LHON can often be confirmed with mutation analysis. Detection of pathogenic mutations and quantification of heteroplasmy has mainly relied on PCR and restriction site analysis and densitometric scanning. We applied the recently developed solid-phase minisequencing method, based on primer-guided nucleotide incorporation, to the simultaneous detection and quantitation of the ND4/11778 and ND1/3460 mutations. The method was highly sensitive, heteroplasmy as low as 1.5% being easily detected. Rapid, reproducible, and accurate results prove solid-phase minisequencing to be the method of choice for quantitative analysis of LHON mutations.

The mitochondrial complex I genes were sequenced in seven Leber hereditary optic neuroretinopathy (LHON) families without the ND4/11,778 and ND1/3460 mutations. Four replacement mutations restricted only to LHON families were found, one in the ND1 gene at nt 4025, and three in the ND5 gene at nt 12,811, 13,637, and 13,967. The mutations did not change evolutionarily conserved amino acids suggesting that they are not primary LHON mutations in these families. They may be considered as secondary LHON mutations serving as exacerbating factors in an appropriate genetic background. A complex III mutation, cyt b/15,257, has been suggested to be one of the primary mutations causing LHON. Its presence was determined for 23 Finnish LHON families, and it was detected in two families harboring the ND4/11,778 mutation. Similarly, complex IV mutation COI/7444 was screened in Finnish LHON families, and it was found in one family carrying the ND1/3460 mutation.

A mutation in the mitochondrial DNA at nt 11,778 has recently been found in Leber hereditary optic neuroretinopathy (LHON), a maternally inherited ocular disease. The mutation is located in the ND4 gene encoding subunit 4 of the respiratory chain enzyme NADH dehydrogenase. The mutation was subsequently not found in 9 of the 20 known Finnish families with LHON, implying that there are at least two different mutations associated with the disease. Using direct sequencing of PCR-amplified mtDNA, we have now sequenced the entire ND4 region in the families without the nt 11,778 mutation to find the other mutations. No new mutations in the ND4 region were found, suggesting that the putative mtDNA mutation in these families may be in the coding regions for other subunits of NADH dehydrogenase enzyme. The sequence of ND4 gene as found to be highly homogeneous.

We have localized a single-copy DNA probe, HU16 (locus DXS26), to Xq21.1. The probe was isolated from a human-mouse hybrid X;13 library and mapped with human-mouse hybrids containing different portions of the human X chromosome and DNA from male patients with different X-chromosomal deletions. The following order of loci is proposed: Xcen-(DXS72, DXS169)-(DXS232,DXS26)-DXS121-DXS233-DXS165 TCD-DXS95-DXYSl-Xqter. HU16 will be useful in the study of the putative genes that reside in Xq21 and whose defects lead to deafness and mental retardation.

Ophthalmologic findings in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy : a cross-sectional study.

Pre-excitation syndrome is common in families with Leber's hereditary optic neuropathy (LHON). 24 Finnish families with LHON were screened for the 11778 and the 3460 mitochondrial DNA mutations. 5 of 30 individuals with LHON and the 11778 mutation had the Wolff-Parkinson- White pre-excitation syndrome. None of 10 with the 3460 mutation or of 11 with "other" mutations had this syndrome. Overall, 5 of 51 LHON patients and 9 of 112 symptom-free maternal relatives had Wolff-Parkinson-White syndrome (9%). In paternal relatives, the frequency was 1·6%. Mitochondrial DNA causal for LHON may contribute to pre-excitation syndrome. Lancet 1994; 344: 857–58

Variation in mitochondrial DNA (mtDNA) in a sample of 110 Finns was analyzed with six restriction enzymes, AvaII, BamHI, HaeII, HindII, HpaI, and MspI, by using total blood cell DNA probed with mouse mtDNA. Two new enzyme morphs were observed, one for HaeII and one for HindII. Double-digestion experiments indicated that the BamHI morphs 2 and 3 result from base changes leading to AvaII morphs 3 and 9, respectively. Of the ten different mtDNA types observed, defined by restriction fragment patterns, seven have been previously described in Caucasoid populations. The three new "Finnish" mtDNA types can be derived from Caucasoid lineages by single restriction site changes. The results were used to reconstruct a phylogenetic tree for Caucasoid mtDNA types defined by the enzymes used. The frequencies of mtDNA types were used to compute genetic distances between Finns, Italians, and Israeli Jews. The frequencies of both enzyme morphs and mtDNA types show that the Finnish population is highly homogeneous.

Interferon-alpha and interferon-gamma production by idiopathic isolated optic neuritis (ON) patients was studied. The production capacity was compared with that in two control groups: patients with iritis and healthy control subjects. A sensitive and reliable interferon bioassay was applied for interferon level measurements. Statistically significant differences were not found between patients and control groups in either interferon-alpha production or interferon-gamma production.

The acute stage of Leber's hereditary optic neuritis is characterized by dilated disc arterioles accompanied, in some cases, by superficial peripapillary hemorrhages. Decreased vision caused by centrocecal scotoma is accompanied by slow and deficient capillary filling in the papillomacular bundle and arteriovenous shunting in the upper and lower vascular arcades. These and other vascular changes disappear in the more advanced stages (optic atrophy) of the disease.

• Clinical, ophthalmoscopic, perimetric, and color vision tests and visual evoked responses were recorded in symptomatic and asymptomatic eyes in five members of a family with Leber hereditary optic atrophy. The presymptomatic eyes showed abnormalities in the retinal nerve fiber layer. Optic nerve dysfunction was found before central vision failed. The appearance of degenerating retinal nerve fibers, particularly in the papillomacular bundle, was documented photographically in the weeks after the onset of visual symptoms. Treatment with prednisone and hydroxocobalamin did not reverse or halt serious impairment of vision. ( Arch Ophthalmol 95:969-978, 1977)

The authors report a patient with ocular flutter associated with pathologically confirmed sarcoidosis and aseptic meningitis. Ocular flutter was the only clinical sign of neurological illness in this patient and it gradually disappeared in two months. This case suggests that neurosar-coidosis is to be considered a potential cause of ocular flutter.