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Biomedical subjects

A T Moore

Publications and source records attributed to A T Moore.

At least 91 records · Page 5Linked to original sources
PubMed1996

Colobomatous microphthalmia with midfacial clefting: part of the spectrum of branchio-oculo-facial syndrome?

A young male infant was noted at birth to have bilateral cleft lip and palate, bilateral microphthalmos and ocular colobomata, and a dysplastic left kidney. His mother had similar ophthalmological findings and milder facial anomalies which included abnormality of the philtrum and bilateral congenital nasolacrimal duct obstruction. His maternal grandmother had mild facial anomalies including a short philtrum and bilateral congenital nasolacrimal duct obstruction but had no evidence of any ocular abnormalities. The spectrum of abnormalities seen in this family are similar to those described in the branchio-oculo-facial syndrome, a rare dominantly inherited syndrome in which there are a number of developmental abnormalities of the eye, face, and kidney. Although the precise cause of this syndrome is unknown, it is likely to be caused by mutations in a gene responsible for the ordered closure of the foetal fissure and fusion of facial structures.

Adult↗
PubMed1995

Localization of the gene for progressive bifocal chorioretinal atrophy (PBCRA) to chromosome 6q.

Progressive bifocal chorioretinal atrophy (PBCRA) is a rare, autosomal dominant congenital chorioretinal dystrophy. We have performed genetic linkage analysis on a five-generation British pedigree. Two-point linkage analysis showed significant linkage with nine microsatellite marker loci mapping to chromosome 6q. Multipoint analysis gave a maximum lod score of 11.8 (theta = 0.05) between D6S249 and D6S283. This region overlaps with that to which the gene for North Carolina macular dystrophy (MCDR1) has been assigned. However, given the range of differences in phenotype between these two retinal disorders, it is likely that different mutation mechanisms are responsible for each disease.

Atrophy↗
PubMed1995

Autosomal dominant retinitis pigmentosa mapping to chromosome 7p exhibits variable expression.

The genetic locus causing autosomal dominant retinitis pigmentosa (adRP) has recently been mapped in a large English family to chromosome 7p. Eight affected members of this family were studied electrophysiologically and psychophysically with dark adapted static threshold perimetry and dark adaptometry. The phenotypes observed fell into three categories: minimally affected with no symptoms, and normal (or near normal) electrophysiology and psychophysics; moderately affected with mild symptoms, abnormal electroretinograms, and equal loss of rod and cone function in affected areas of the retina; and severely affected with extinguished electroretinograms and barely detectable dark adapted static threshold sensitivities. The mutation in the gene on 7p causing adRP in this family causes regional retinal dysfunction with greatly variable expressivity ranging from normal to profoundly abnormal in a manner not explained by age.

Adult↗
PubMed1995

Infantile presentation of X linked retinoschisis.

Five infants who presented with nystagmus and/or strabismus were found to have bilateral highly elevated bullous retinoschisis involving the macula. Haemorrhage was present within the schisis cavity or the vitreous in four patients. The bullous retinoschisis eventually reattached spontaneously leaving pigment demarcation lines. A family history of X linked retinoschisis (XLRS) was known in two of the patients but in the other three subsequent investigation showed other male family members to be affected. It is important to recognise this uncommon presentation of XLRS so that the correct diagnosis is made and appropriate genetic counselling is given. Surgical treatment is not usually indicated and the visual prognosis is better than the initial appearance may suggest.

Electroretinography↗
PubMed1995

Ischaemic retinopathy occurring in patients receiving bone marrow allografts and campath-1G: a clinicopathological study.

AIMS/BACKGROUND: Ischaemic retinopathy is a well characterised complication of bone marrow transplantation (BMT). Although the aetiology is unclear, it is most probably multifactorial, and may be related to treatment such as radiation and cyclosporin A. The clinical findings are reported of two patients who developed such a retinopathy and the ocular histology from one of these cases is presented. METHODS: Two patients underwent BMT for acute lymphoblastic leukaemia, receiving campath-1G for prophylaxis against graft versus host disease, and showed fundal changes compatible with BMT retinopathy. The eyes from one patient were retrieved at post mortem and examined by both light and electron microscopy. RESULTS: The visual symptoms and fundal signs resolved spontaneously with no specific treatment in one patient. Light and electron microscopic examination of the eyes of the other patient was compatible with an ischaemic aetiology and showed evidence of retinal capillary endothelial loss. CONCLUSIONS: (i) Histopathology in one case of BMT retinopathy demonstrates a retinal endotheliopathy similar to that described in radiation retinopathy. (ii) BMT retinopathy may occur in the absence of cyclosporin A treatment. (iii) The retinopathy can recover spontaneously with no specific treatment.

Adult↗
PubMed1995

Bimodal expressivity in dominant retinitis pigmentosa genetically linked to chromosome 19q.

A clinical, psychophysical, and electrophysiologic study was undertaken of two autosomal dominant retinitis pigmentosa pedigrees with a genetic mutation assigned to chromosome 19q by linkage analysis. Members with the abnormal haplotype were either symptomatic with adolescent onset nyctalopia, restricted visual fields, and non-detectable electroretinographic responses by 30 years of age, or asymptomatic with normal fundus appearance and minimal or no psychophysical or electroretinographic abnormalities. There was no correlation in the severity in parents and their offspring. Pedigree analysis suggested that although the offspring of parents with the genetic mutation were at 50% risk of having the genetic defect, the risk of being symptomatic during a working lifetime was only 31%. Such bimodal phenotypic expressivity in these particular pedigrees may be explained by a second, allelic genetic influence and may be a phenomenon unique to this genetic locus. Genetic counselling in families expressing this phenotype can only be based on haplotype analysis since clinical investigations, even in the most elderly, would not preclude the presence of the mutant gene.

Adult↗
PubMed1995

Clinical features and molecular genetics of Von Hippel-Lindau disease.

Although familial cancer syndromes are rare, a knowledge of these disorders is relevant to both clinicians and basic scientists. This is exemplified by Von Hippel-Lindau (VHL) disease which is caused by germline mutations in the VHL tumour suppressor gene. This multisystem disorder provides a complex clinical problem for ophthalmologists and other specialists. In addition, recent advances in the molecular genetics of this disorder are providing novel insights into the molecular mechanisms of tumourigenesis in VHL disease and in more common nonfamilial neoplasms such as clear cell renal carcinoma and central nervous system haemangioblastoma. In this review, we describe the clinical manifestations (with particular reference to the ocular complications) and the molecular genetics of VHL disease.

Angiomatosis↗
PubMed1994

Identification of a sixth locus for autosomal dominant retinitis pigmentosa on chromosome 19.

We report the mapping of a sixth locus for autosomal dominant retinitis pigmentosa (adRP) to 19q13.4. After a total genome linkage search using over 300 markers in a single large pedigree, marker loci on the long arm of chromosome 19 showed significant linkage with the disease locus. Since the mapping information for the marker loci used in this study was derived from two different genome maps, we established genetic distances between relevant marker loci so that linkage information could be combined from both maps. A conventional three point analysis between the adRP phenotype and markers D19S180 and D19S214 gave a maximum lod score of 4.87. Combining data from these and other markers, we used the recently described multiple two point programme FASTMAP to simulate a multipoint analysis of the full data set. This gave a lod score of 5.34 in the interval between markers D19S180 and D19S214. Recently this laboratory has also reported the linkage of another form of retinal degeneration known as cone-rod dystrophy (CRD) to a genetically different set of markers from 19q. Linkage data presented here clearly supports the existence of two separate retinal genes in this part of the genome.

Chromosome Mapping↗
PubMed1994

Molecular genetic analysis of the 3p- syndrome.

Molecular genetic analysis of five cases of 3p- syndrome (del(3)(qter-->p25:)) was performed to investigate the relationship between the molecular pathology and clinical phenotype. Fluorescence in situ hybridization studies and analysis of polymorphic DNA markers from chromosome 3p25-p26 demonstrated that all four informative cases had distal deletions. However, the extent of the deletion was variable: in two patients with the most extensive deletions the deletion breakpoint mapped between RAF1 and D3S1250, in one patient the deletion breakpoint was between D3S1250 and D3S601, and in two patients the deletion commenced telomeric to D3S601 (and telomeric to D3S1317 in one of these). All five patients displayed the classical features of 3p- syndrome (mental retardation, growth retardation, microcephaly, ptosis and micrognathia) demonstrating that loss of sequences centromeric to D3S1317 is not required for expression of the characteristic 3p- syndrome phenotype. The three patients with the most extensive deletions had cardiac septal defects suggesting that a gene involved in normal cardiac development is contained in the interval D3S1250 and D3S18. The PMCA2 gene is contained within this region and deletion of this gene may cause congenital heart defects. At least three patients were deleted for the von Hippel-Lindau (VHL) disease gene although none had yet developed evidence of VHL disease. We conclude that molecular analysis of 3p- syndrome patients enhances the management of affected patients by identifying those at risk for VHL disease, and can be used to elucidate the critical regions for the 3p- syndrome phenotype.

Abnormalities, Multiple↗
PubMed1994

Colour vision screening in glaucoma: the Tritan Album and other simple tests.

Results from simple colour vision tests used for the detection of the Type III colour vision deficiency in glaucoma and ocular hypertension are presented. We assessed 49 patients with primary open angle glaucoma, 16 ocular hypertensives, 54 age matched normals and 50 young normal observers using six established tests and the recently introduced Tritan Album. This test was introduced specifically for acquired colour vision deficiencies. Results show in general that individual tests have low sensitivity and poor screening efficiency. The best screening efficiency was achieved by the City University Colour Vision Test and the AO HRR plate test, no acquired tritan defects were identified by the Farnsworth F2 plate, and the Tritan Album had very low sensitivity (the lowest excluding the F2 plate). Best results were obtained from a combination of City University and HRR test scores and this combination could provide useful additional data on colour vision in a glaucoma screening programme.

Aged↗
PubMed1994

Carrier detection in X linked ocular albinism using linked DNA polymorphisms.

Sixty two females at 50% carrier risk were assessed from 19 families affected by X linked ocular albinism (OA1). Twenty nine (47%) had definite fundus changes of the carrier state with a mud splattered fundus appearance and 23 (37%) had a normal ophthalmic examination. Ten (16%) had mild peripheral retinal pigmentary changes so that it was difficult to exclude the carrier state; six of these females were shown to be at low risk and only one at high risk of being a carrier by DNA analysis using linked DNA polymorphisms, including a highly informative dinucleotide repeat at the Kallmann locus. Mild peripheral retinal pigmentary changes are not a definite indication of carrier status and in 45 age matched female controls five (11%) had similar changes. No female with a clinically normal fundus was found to be at high risk by DNA analysis. Molecular genetic analysis improves the accuracy of carrier detection in OA1 families and should be considered if the clinical findings are equivocal.

Albinism, Ocular↗
PubMed1994

Further refinement of the location for autosomal dominant retinitis pigmentosa on chromosome 7p (RP9).

A form of autosomal dominant retinitis pigmentosa (adRP) mapping to chromosome 7p was recently reported by this laboratory, in a single large family from southeastern England. Further sampling of the family and the use a number of genetic markers from 7p have facilitated the construction of a series of multipoint linkage maps of the region with the most likely disease gene location. From this and haplotype data, the locus can now be placed between the markers D7S484 and D7S526, in an interval estimated to be 1.6-4 cM. Genetic distances between the markers previously reported to be linked to this region and those described in the recent whole-genome poly-CA map were estimated from data in this and other families. These data should assist in the construction of a physical map of the region and will help to identify candidate genes for the 7p adRP locus.

Chromosome Mapping↗
PubMed1993

Genetic mapping of X-linked ocular albinism: linkage analysis in a large Newfoundland kindred.

Genetic linkage studies in a large Newfoundland family affected by X-linked ocular albinism (OA1) showed linkage to markers from Xp22.3. One recombinant mapped the disease proximal to DXS143 (dic56) and two recombinants mapped the disease distal to DXS85 (782). Combining the data with that from 16 British families previously published confirmed close linkage between OA1 and DXS143 (dic56; Zmax = 21.96 at theta = 0.01, confidence interval (CI) 0.0005-0.05) and linkage to DXS85 (782; Zmax = 17.60 at theta = 0.07, CI = 0.03-0.13) and DXS237 (GMGX9; Zmax = 15.20 at theta = 0.08, CI = 0.03-0.15). Multipoint analysis (LINKMAP) gave the most likely order as Xpter-XG-DXS237-DXS 143-OA1-DXS85, with odds of 48:1 over the order Xpter-XG-DXS237-OA1-DXS143-DXS85, and odds exceeding 10(10):1 over other locations for the disease locus.

Albinism, Ocular↗
PubMed1993

A new locus for autosomal dominant retinitis pigmentosa on chromosome 7p.

Autosomal dominant retinitis pigmentosa (adRP) is known to result from mutations in two different retinal genes--rhodopsin and peripherin--while a third locus has been implicated by linkage data. However, families have been reported in which all three known loci have been excluded. We report linkage of adRP in one such family to two microsatellite markers on chromosome 7p. D7S435 has previously been localized to 7p13-15.1; D7S460, previously only localized to chromosome 7, maps to within 2 cM of D7S435 with a lod score of 12.15. Two point linkage analysis between these markers and adRP gave lod scores of 5.65 (theta = 0) and 4.19 (theta = 0.046) for D7S460 and D7S435, respectively. Multipoint analysis gave a maximum lod score of 8.22. These data strongly suggest a new adRP locus on chromosome 7p.

Base Sequence↗
PubMed1993

Clinical features of affected males with X linked ocular albinism.

Seventy four males affected by X linked ocular albinism (XLOA) from 19 pedigrees were examined to assess phenotypic variation and visual prognosis. Nystagmus was present in all cases except one. Best visual acuity ranged from 6/9 to 6/60; 79.7% could see 6/36 or better; most could read N5. Marked iris translucency and foveal hypoplasia were present in all cases. Posterior embryotoxon was present in 30% and dysplastic optic discs were often seen. Pigmentation of the posterior pole was associated with better visual acuity. XLOA is under-diagnosed: almost 20% of cases had been previously diagnosed as having congenital nystagmus until reviewed in this study.

Adolescent↗
PubMed1993

Autosomal dominant retinitis pigmentosa with apparent incomplete penetrance: a clinical, electrophysiological, psychophysical, and molecular genetic study.

Twenty five symptomatic individuals and six asymptomatic obligate gene carriers from four families with autosomal dominant retinitis pigmentosa (adRP) showing apparent incomplete penetrance have been studied. Symptomatic individuals from three families showed early onset of night blindness, non-recordable rod electroretinograms, and marked elevation of both rod and cone thresholds in all subjects tested. In the fourth family, there was more variation in the age of onset of night blindness and some symptomatic individuals showed well preserved rod and cone function in some retinal areas. All asymptomatic individuals tested had evidence of mild abnormalities of rod and cone function, indicating that these families show marked variation in expressivity rather than true non-penetrance of the adRP gene. No mutations of the rhodopsin or RDS genes were found in these families and the precise genetic mutation(s) remain to be identified.

Adolescent↗