Hereditary optic atrophy. An autosomal dominant with incomplete penetrance

Towards a matrix mechanics framework for dynamic protein network

Protein–protein interaction networks are currently visualized by software generated interaction webs based upon static experimental data. Current state is limited to static, mostly non-compartmental network and non time resolved protein interactions. A satisfactory mathematical foundation for particle interactions within a viscous liquid state (situation within the cytoplasm) does not exist nor do current computer programs enable building dynamic interaction networks for time resolved interactions. Building mathematical foundation for intracellular protein interactions can be achieved in two increments (a) trigger and capture the dynamic molecular changes for a select subset of proteins using several model systems and high throughput time resolved proteomics and, (b) use this information to build the mathematical foundation and computational algorithm for a compartmentalized and dynamic protein interaction network. Such a foundation is expected to provide benefit in at least two spheres: (a) understanding physiology enabling explanation of phenomenon such as incomplete penetrance in genetic disorders and (b) enabling several fold increase in biopharmaceutical production using impure starting materials.

Dominant optic atrophy: correlation between clinical and molecular genetic studies

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 < or = 20 years. Ten out of 20 affected individuals followed up for > or = 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.

Dominant optic atrophy. Refining the clinical diagnostic criteria in light of genetic linkage studies

OBJECTIVE

To describe the clinical findings and refine the clinical diagnostic criteria for dominant optic atrophy based on eight British families in which the diagnosis was confirmed by linkage analysis.

DESIGN AND PARTICIPANTS

Case series; 92 subjects in 8 pedigrees had both eyes examined.

INTERVENTION

Family members received a domiciliary examination based on best-corrected visual acuity, color vision using Ishihara and Hardy Richter Rand (HRR) plates, confrontation field testing using a red target, and optic disc evaluation using a direct ophthalmoscope. Genomic DNA was extracted from leukocytes or buccal mucosal cells and genotyped using 12 fluorescently labeled microsatellite markers from the region 3q27-q29.

MAIN OUTCOME MEASURES

Subjects were classified clinically as definitely or possibly affected on the basis of the domiciliary examination before genetic analysis, and these results were compared with the haplotype analysis.

RESULTS

Clinically, 43 subjects were identified as definitely affected, 4 as possibly affected, and 45 as unaffected. Visual acuity in affected subjects ranged from 6/6 to count fingers and declined with age. On genetic analysis, a haplotype was identified in each family, which was found in all definitely affected members but not in those regarded as unaffected. The four possibly affected individuals also bore the haplotype that segregated with the disease.

CONCLUSIONS

Simple clinical tests are highly efficacious in diagnosing dominant optic atrophy. Contrary to accepted criteria, symptoms begin before the age of 10 years in only 58% of affected individuals. Visual acuity in affected subjects is highly variable. A mild degree of temporal or diffuse pallor of the optic disc and minimal color vision defects, in the context of a family with dominant optic atrophy, are highly suggestive of an individual being affected, even if the visual acuity is normal. This widens the generally accepted diagnostic criteria for this disease.

Dominant optic atrophy mapped to chromosome 3q region. II. Clinical and epidemiological aspects

Sixty-two patients from three large Danish families with autosomal dominant optic atrophy were clinically examined, and retrospective follow-up was made on 30 patients. We found great inter-and intrafamiliar variation in visual acuity and visual decline. One hundred and seventy-five chromosomal markers were analyzed in 118 family members. Linkage was demonstrated between the disease gene (OPA1) and the microsatellite markers D3S1314, D3S1262, D3S1265 and D3S1601, with the highest Lod score to D3S1601 Z=11.75. All markers are located on chromosome 3q in the telomeric area, the most probable location for the OPA1 gene being D3S1601-OPA1-D3S1265. Using data from the Danish Family Register of Hereditary Eye Diseases, the minimum prevalence rate was estimated to 1:12.301, making DOA the most common hereditary optic atrophy.