Contribution of post-receporal cells to the cone a-wave of the human electroretinogram in congenital stationary night blindness and autoimmune-like retinopathy.

In normal subjects the later part of the cone a-wave to a brief flash increases in amplitude after 50-100 ms darkness due to a contribution from secondary hyperpolarising cells. We recorded these responses along with clinical ON and OFF ERGs in patients with inner retinal dysfunction to see if this part of the a-wave is affected. Patients with autoimmune-like retinopathy and CSNB2 had abnormal ON and OFF responses but the a-wave increased in amplitude in the dark as in normals.

The PROM1 mutation p.R373C causes an autosomal dominant bull's eye maculopathy associated with rod, rod-cone, and macular dystrophy.

Purpose: To characterize in detail the phenotype of five unrelated families with autosomal dominant bull's eye maculopathy (BEM) due to the R373C mutation in the PROM1 gene.

Methods: Forty-one individuals of five families of Caribbean (family A), British (families B, D, E), and Italian (family C) origin, segregating the R373C mutation in PROM1, were ascertained. Electrophysiological assessment, fundus autofluorescence (FAF) imaging, fundus fluorescein angiography (FFA), and optical coherence tomography (OCT) were performed in available subjects.

Contribution of post-receptoral cells to the a-wave of the human photopic electroretinogram.

ERGs were recorded to red flashes (0.01-50 phcdsm(2)) presented against a steady background (2000 sctd) or 0-300 ms after its suppression. The cone a-wave was altered in form and increased in amplitude in the dark.

Cone-rod dystrophy, intrafamilial variability, and incomplete penetrance associated with the R172W mutation in the peripherin/RDS gene.

Purpose: To determine the underlying molecular genetic basis of a retinal dystrophy identified in a 5-generation family, and to examine the phenotype and degree of intrafamilial variability.

Design: Family genetic study.

Participants: Nine affected individuals from a nonconsanguineous British family.

X-linked cone dysfunction syndrome with myopia and protanopia.

Purpose: To perform a detailed clinical, psychophysical, and molecular assessment of members of 4 families with an unusual X-linked cone dysfunction syndrome associated with myopia.

Participants: Affected and unaffected members of 4 British nonconsanguineous families.

Methods: Subjects underwent both detailed clinical examination and psychophysical testing.

Identification of novel RPGR ORF15 mutations in X-linked progressive cone-rod dystrophy (XLCORD) families.

Purpose: To test the incidence of mutations in RPGR ORF15 in six families with X-linked progressive retinal degeneration (cone-rod dystrophy [XLCORD], macular or cone dystrophy) and to undertake a detailed phenotypic assessment of families in whom ORF15 mutations were identified.

Methods: To amplify and sequence ORF15 in its entirety, a cloning strategy was developed. Families with mutations in ORF15 underwent electrophysiological testing, color vision assessment, color fundus photography, and fundus autofluorescence (AF) imaging.

Comparison of ERGs recorded with skin and corneal-contact electrodes in normal children and adults.

Purpose: Compare electroretinogram (ERG) responses to full-field stimuli recorded with corneal-contact and skin electrodes in healthy children and adults.

Method: ERGs were recorded independently in two laboratories in children (aged 4-14 years) and adults (aged 20-62 years). A Burian-Allen (BA) electrode were used to test both children and adults in one laboratory.

A comparison of ERG abnormalities in XLRS and XLCSNB.

Dark and light adapted ERGs were recorded in 19 patients with XLRS and in 15 patients with CSNB. Patients were assigned to clinical groups after identification of mutations in the RS1 (16 patients), NYX (11 patients) and CACNA1F (4 patients) genes causing XLRS, 'complete' CSNB and 'incomplete' CSNB, respectively. ERG responses were compared with those of 26 healthy volunteers.

Abnormalities of the scotopic threshold response correlated with gene mutation in X-linked retinoschisis and congenital stationary night blindness.

STRs and dark-adapted ERGs were recorded in nine normal subjects, nine patients with XLRS, 11 patients with CSNB1 and one patient with CSNB2. In XLRS STR amplitude was significantly lower than normal at every intensity, but the response could be recorded in every patient and the maximum amplitude response was outside the 95% confidence limits in only four of the nine patients. STRs were significantly poorer in patients with CSNB and a responses was not measurable at any intensity in nine of the 11 patients with CSNB1.

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.

Mutations in the CACNA1F and NYX genes in British CSNBX families.

X-linked congenital stationary night blindness (CSNBX) is a genetically and phenotypically heterogeneous non-progressive disorder, characterised by impaired night vision but grossly normal retinal appearance. Other more variable features include reduction in visual acuity, myopia, nystagmus and strabismus. Genetic mapping studies by other groups, and our own studies of British patients, identified key recombination events indicating the presence of at least 2 disease genes on Xp11.