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Biomedical subjects

B P Leroy

Publications and source records attributed to B P Leroy.

At least 19 recordsLinked to original sources
PubMed2006

Two cases of acute macular neuroretinopathy.

PURPOSE: To report chorioretinal vasoconstriction as a potential pathogenic mechanism in acute macular neuroretinopathy (AMNR). To describe a time lag between the onset of functional deficits and that of fundoscopically visible lesions and illustrate the superior value of infrared (IR) compared to red-free or white light imaging in AMNR. METHODS: Two young female patients (30 and 19 years old) with AMNR are described. Both underwent detailed clinical examination with additional imaging using IR, blue, and red-free light. Functional evaluation with pattern and multifocal electroretinography, Goldmann manual, and automated Humphrey visual fields (VFs) was also performed. RESULTS: The first patient was diagnosed with AMNR after a caesarian section during and after which she received treatment with vasoconstrictive drugs. She was followed up for 28 months, after which time she still suffered from bilateral U-shaped paracentral scotomata associated with macular lesions. The second patient complained of central scotomata prior to the onset of any visible fundoscopic lesions, following a bout of flu. VFs confirmed a central scotoma and pattern electroretinography was consistent with loss of macular function. Bilateral petaloid lesions became visible after 3 days when function began to improve. In both patients IR imaging was superior to standard red-free and white light in identifying macular lesions. CONCLUSIONS: Vasoconstriction in the chorioretina may be pathogenic in AMNR. Functional complaints precede fundus lesions in AMNR. And, IR light is superior to red-free or white light imaging in detecting typical fundus lesions in AMNR both early and late in the course of the disease.

Acute Disease↗
PubMed2006

Intrafamilial phenotypic variability in families with RDS mutations: exclusion of ROM1 as a genetic modifier for those with retinitis pigmentosa.

OBJECTIVES: To identify suspected RDS mutations in families in which different people have been identified with either generalised retinal dystrophy or macular dystrophy. METHODS: Two families with a retinal dystrophy were extensively phenotyped and blood was taken for mutation analysis of the RDS (all) and ROM1 (retinitis pigmentosa patients only) genes. RESULTS: A novel p.Trp94X mutation in RDS was found in all three affected members of a two-generation family that was associated with retinitis pigmentosa in the son, pattern dystrophy in the daughter and fundus flavimaculatus in the mother. In the second family, the proband with retinitis pigmentosa carried a p.Arg220Trp mutation. The mother, who was unavailable for mutation screening, had adult vitelliform macular dystrophy. No ROM1 mutations were found in those with retinitis pigmentosa in either family. CONCLUSION: Mutations in RDS can be associated with an intrafamilial variation in retinal disease. The phenotypes range from Stargardt-like macular dystrophy to classic retinitis pigmentosa. CLINICAL RELEVANCE: Intrafamilial phenotypic variation may be due to the presence of environmental or genetic modifying factors. The presence of a modifying-sequence change in the coding region of ROM1 for two people with retinitis pigmentosa from two families with intrafamilial variation in RDS mutation phenotype has been excluded in this study.

Adult↗
PubMed2006

Visceral and testicular calcifications as part of the phenotype in pseudoxanthoma elasticum: ultrasound findings in Belgian patients and healthy carriers.

Occasionally calcifications in abdominal organs, breasts and testicles have been reported in pseudoxanthoma elasticum (PXE) patients. In the present study, an ultrasound evaluation was performed of the abdomen and--in male patients--of the testicles in 17 PXE patients and 17 heterozygous carriers. Blood samples were taken to evaluate calcium load, liver and kidney function. Calcifications in liver, kidneys and spleen were detected in 59% of the patients and in 23.5% of healthy carriers. Parameters of kidney and liver function were normal in both groups, suggesting that the calcifications have no direct effect on organ function. Testicular ultrasound revealed parenchymous calcifications in all males investigated. Widespread, small hyperechogenic foci resembling testicular microlithiasis were seen. In some carriers, focal calcifications were identified. The current data suggest that visceral and testicular calcifications are part of the phenotype of PXE patients. Their presence in some of the healthy carriers are suggestive of subclinical manifestations in these relatives. The natural history and long-term effects of the parenchymal calcifications remain to be elucidated. As testicular microlithiasis may be associated with a higher risk for malignancy, regular clinical and ultrasound follow-up seems indicated in these patients.

Adolescent↗
PubMed2005

Retinal vessel dilation following repletion of vitamin A deficiency.

We hypothesized that because depletion of vitamin A blocks the initiation of phototransduction, such inhibition of functional activation should lead to decrease retinal metabolism and perfusion. In a case study of a vitamin A-depleted patient, we found that retinal vessel diameters, a surrogate measure of retinal perfusion, increased in concert with the restitution of electroretinographic function following vitamin A supplementation. When normalized to conditions after treatment, the relative magnitude of study parameters at presentation were: scotopic electroretinography B-wave amplitude 1.2%, photopic electroretrinography B-wave amplitude 23%, retinal vein diameter 88%, retinal artery diameter 94%. These observations support that activation of the visual process results in increased retinal metabolism and perfusion.

Adult↗
PubMed2005

Deletions involving long-range conserved nongenic sequences upstream and downstream of FOXL2 as a novel disease-causing mechanism in blepharophimosis syndrome.

The expression of a gene requires not only a normal coding sequence but also intact regulatory regions, which can be located at large distances from the target genes, as demonstrated for an increasing number of developmental genes. In previous mutation studies of the role of FOXL2 in blepharophimosis syndrome (BPES), we identified intragenic mutations in 70% of our patients. Three translocation breakpoints upstream of FOXL2 in patients with BPES suggested a position effect. Here, we identified novel microdeletions outside of FOXL2 in cases of sporadic and familial BPES. Specifically, four rearrangements, with an overlap of 126 kb, are located 230 kb upstream of FOXL2, telomeric to the reported translocation breakpoints. Moreover, the shortest region of deletion overlap (SRO) contains several conserved nongenic sequences (CNGs) harboring putative transcription-factor binding sites and representing potential long-range cis-regulatory elements. Interestingly, the human region orthologous to the 12-kb sequence deleted in the polled intersex syndrome in goat, which is an animal model for BPES, is contained in this SRO, providing evidence of human-goat conservation of FOXL2 expression and of the mutational mechanism. Surprisingly, in a fifth family with BPES, one rearrangement was found downstream of FOXL2. In addition, we report nine novel rearrangements encompassing FOXL2 that range from partial gene deletions to submicroscopic deletions. Overall, genomic rearrangements encompassing or outside of FOXL2 account for 16% of all molecular defects found in our families with BPES. In summary, this is the first report of extragenic deletions in BPES, providing further evidence of potential long-range cis-regulatory elements regulating FOXL2 expression. It contributes to the enlarging group of developmental diseases caused by defective distant regulation of gene expression. Finally, we demonstrate that CNGs are candidate regions for genomic rearrangements in developmental genes.

Animals↗
PubMed2005

Myopia: more than a refractive error--LASIK and retinal dystrophies.

Three patients who had undergone laser in situ keratomileusis (LASIK) correction for myopia were first seen because of suboptimal visual acuity (VA) and night blindness and/or photophobia. After a comprehensive examination including psychophysical and electrophysiological tests, two of the three patients were shown to suffer from a progressive conerod dystrophy. The third patient had retinitis pigmentosa. These cases illustrate the need for in depth preoperative evaluation in myopic patients about to undergo LASIK when signs or problems of night blindness and/or photophobia are present.

Adult↗
PubMed2004

A new type of autosomal recessive spondyloepiphyseal dysplasia tarda.

Repeated occurrence of a hitherto unrecognized form of spondyloepiphyseal dysplasia tarda (SED tarda) has been studied in two independent families. Because parental consanguinity was also present in one family, autosomal recessive inheritance is proposed. The onset was in late childhood. The slowly evolving disorder shared several features of the already known types of SED tarda. The radiographic abnormalities were limited to the spine and proximal femora. The patients' hands were normal. The entity described is set apart not only from the X-linked and autosomal-dominant forms of SED tarda but also from the already delineated autosomal recessive types by significant clinical and radiographic differences. Final genotypic characterization must await the results of genetic linkage studies and of appropriate molecular genetics investigations.

Adolescent↗
PubMed2004

Progressive cone dystrophy and sensorineural hearing loss.

A 39-year old man presented 13 years ago with a history of progressive loss of vision and photophobia. A full ophthalmological and ENT work-up during several years of follow-up, including psychophysical as well as electrophysiological tests, revealed a progressive cone dystrophy in combination with sensorineural hearing loss. His younger sister presented with very similar features and underwent the same work-up. A novel syndrome of progressive cone dystrophy and sensorineural hearing loss is described in both siblings. Both also suffered from non-ocular disease possibly related to ciliary dysfunction. The condition is likely to be inherited as an autosomal recessive trait.

Adult↗
PubMed2003

The contribution of USH1C mutations to syndromic and non-syndromic deafness in the UK.

Denaturing high-performance liquid chromatography (DHPLC) was used to screen 14 UK patients with Usher syndrome type 1, in order to assess the contribution of mutations in USH1C to type 1 Usher. In addition, 16 Caucasian sib pairs and two small consanguineous families with non-syndromic deafness, who were concordant for haplotypes around DFNB18, were also screened for mutations in the USH1C gene. Two Usher type 1 patients were found to have the 238-239insC mutation reported previously; one of Greek Cypriot origin was homozygous for the mutation and another Caucasian was heterozygous. This indicates that mutations in the USH1C gene make a greater contribution to Usher syndrome type 1 than originally thought, which has implications for the genetic testing of families with Usher syndrome in the UK. Analysis using intragenic single nucleotide polymorphisms (SNPs) revealed that the haplotypic background bearing this common mutation was not consistent across the gene in two families, and that there are either two haplotypes on which the mutation has arisen or that there has been a recombination on a single haplotype. We found no evidence of mutations in USH1C in the patients with non-syndromic deafness, suggesting that the gene is not a major contributor to autosomal-recessive non-syndromic deafness in the UK.

Adaptor Proteins, Signal Transducing↗
PubMed2003

Alport syndrome and conjunctival telangiectasia.

We report a patient with ocular abnormalities due to Alport syndrome. Considerable improvement of visual acuity was obtained following ocular lens extraction with foldable lens implantation in the right eye to compensate the effect of the lenticonus anterior. The presence of conjunctival telangiectasia is a new clinical finding in a patient with Alport syndrome.

Adult↗
PubMed2001

Spectrum of FOXL2 gene mutations in blepharophimosis-ptosis-epicanthus inversus (BPES) families demonstrates a genotype--phenotype correlation.

Mutations in FOXL2, a forkhead transcription factor gene, have recently been shown to cause blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) types I and II, a rare genetic disorder. In BPES type I a complex eyelid malformation is associated with premature ovarian failure (POF), whereas in BPES type II the eyelid defect occurs as an isolated entity. In this study, we describe the identification of novel mutations in the FOXL2 gene in BPES types I and II families, in sporadic BPES patients, and in BPES families where the type could not be established. In 67% of the patients studied, we identified a mutation in the FOXL2 gene. In total, 21 mutations (17 of which are novel) and one microdeletion were identified. Thirteen of these FOXL2 mutations are unique. In this study, we demonstrate that there is a genotype--phenotype correlation for either types of BPES by the finding that mutations predicted to result in a truncated protein either lacking or containing the forkhead domain lead to BPES type I. In contrast, duplications within or downstream of the forkhead domain, and a frameshift downstream of them, all predicted to result in an extended protein, cause BPES type II. In addition, in 30 unrelated patients with isolated POF no causal mutations were identified in FOXL2. Our study provides further evidence that FOXL2 haploinsufficiency may cause BPES types I and II by the effect of a null allele and a hypomorphic allele, respectively. Furthermore, we propose that in a fraction of the BPES patients the genetic defect does not reside within the coding region of the FOXL2 gene and may be caused by a position effect.

Alleles↗
PubMed2001

Spectrum of mutations in USH2A in British patients with Usher syndrome type II.

Usher syndrome (USH) is a combination of a progressive pigmentary retinopathy, indistinguishable from retinitis pigmentosa, and some degree of sensorineural hearing loss. USH can be subdivided in Usher type I (USHI), type II (USHII) and type III (USHIII), all of which are inherited as autosomal recessive traits. The three subtypes are genetically heterogeneous, with six loci so far identified for USHI, three for USHII and only one for USHIII. Mutations in a novel gene, USH2A, encoding the protein usherin, have recently been shown to be associated with USHII. The gene encodes a protein with partial sequence homology to both laminin epidermal growth factor and fibronectin motifs. We analysed 35 British and one Pakistani Usher type II families with at least one affected member, for sequence changes in the 20 translated exons of the USH2A gene, using heteroduplex analysis and sequencing. Probable disease-causing mutations in USH2A were identified in 15 of 36 (41.7%) Usher II families. The most frequently encountered mutation (11/15 families or 11/18 mutated alleles) was del2299G in exon 13, resulting in a frameshift and premature stop codon. Other mutations include insertions and point mutations, of which two are previously unreported. Five different polymorphisms were also detected. Our results indicate that mutations in this gene are responsible for disease in a large proportion of British Usher type II patients. Moreover, if screening for mutations in USH2A is considered, it is sensible to screen for the del2299G mutation first.

Chromosome Deletion↗
PubMed2001

Clinical and electrophysiological findings in autosomal dominant vitreoretinochoroidopathy: report of a new pedigree.

PURPOSE: To report the clinical and electrophysiological findings in a three-generation pedigree with autosomal dominant vitreoretinochoroidopathy. METHODS: Sixteen members of a three-generation pedigree with autosomal dominant vitreoretinochoroidopathy were examined clinically, including measurement of the corneal diameter. In 14 persons, Goldmann perimetry, axial length determination and electro-oculography were carried out. Electroretinography, according to ISCEV standards, was performed in 11 of 12 affected persons. RESULTS: Characteristic annular peripheral pigmentary changes were present in all affected members, as well as chorioretinal atrophy varying from a tigroid aspect to marked atrophy. Four patients presented a microcornea and shallow anterior chamber without microphthalmia. The visual fields appeared to narrow with ageing. The electro-oculography was pathological in the affected patients and normal in the unaffected. The electroretinographic amplitude responses tended to worsen with age, with maintenance of near normal latencies. CONCLUSION: The clinical presentation of autosomal dominant vitreoretinopathy is variable. Electrooculography seems to be a discriminative test. The condition may be associated with anterior segment abnormalities other than presenile cataract, such as microcornea, shallow anterior chamber and angle closure glaucoma.

Adult↗
PubMed2001

Mesopic visual acuity requirements for driving licenses in the European Union-Research Report.

In this study different methods for determining the mesopic visual acuity in candidates for driving licenses group 2 are presented (Royal Decree, 1998, European norms). Results of normal subjects are compared. Depending on the method used, visual acuity obtained under mesopic conditions, with an illuminance of 1 lux, showed a mean ranging from 0.5 to 0.65, which is clearly above the legal norm of 0.2. A comparative study of the three published official norms demonstrates that the stringent norms of 1966 do not match those of 1988 and 1998, resulting in a wider margin of acceptability, to the advantage of the candidate.

Adult↗
PubMed2000

Chromosomal duplication involving the forkhead transcription factor gene FOXC1 causes iris hypoplasia and glaucoma.

The forkhead transcription factor gene FOXC1 (formerly FKHL7) is responsible for a number of glaucoma phenotypes in families in which the disease maps to 6p25, although mutations have not been found in all families in which the disease maps to this region. In a large pedigree with iris hypoplasia and glaucoma mapping to 6p25 (peak LOD score 6.20 [recombination fraction 0] at D6S967), no FOXC1 mutations were detected by direct sequencing. However, genotyping with microsatellite repeat markers suggested the presence of a chromosomal duplication that segregated with the disease phenotype. The duplication was confirmed in affected individuals by FISH with markers encompassing FOXC1. These results provide evidence of gene duplication causing developmental disease in humans, with increased gene dosage of either FOXC1 or other, as yet unknown genes within the duplicated segment being the probable mechanism responsible for the phenotype.

Chromosomes, Human, Pair 6↗
PubMed2000

Prevalence of AIPL1 mutations in inherited retinal degenerative disease.

Leber congenital amaurosis (LCA) is the most severe form of inherited retinal dystrophy and the most frequent cause of inherited blindness in children. LCA is usually inherited in an autosomal recessive fashion, although rare dominant cases have been reported. One form of LCA, LCA4, maps to chromosome 17p13 and is genetically distinct from other forms of LCA. We recently identified the gene associated with LCA4, AIPL1 (aryl-hydrocarbon interacting protein-like 1) and identified three mutations that were the cause of blindness in five families with LCA. In this study, AIPL1 was screened for mutations in 512 unrelated probands with a range of retinal degenerative diseases to determine if AIPL1 mutations cause other forms of inherited retinal degeneration and to determine the relative contribution of AIPL1 mutations to inherited retinal disorders in populations worldwide. We identified 11 LCA families whose retinal disorder is caused by homozygous or compound heterozygous AIPL1 mutations. We also identified affected individuals in two apparently dominant families, diagnosed with juvenile retinitis pigmentosa or dominant cone-rod dystrophy, respectively, who are heterozygous for a 12-bp AIPL1 deletion. Our results suggest that AIPL1 mutations cause approximately 7% of LCA worldwide and may cause dominant retinopathy.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Novel locus for autosomal recessive cone-rod dystrophy CORD8 mapping to chromosome 1q12-Q24.

PURPOSE: To map the disease locus of a two-generation, consanguineous Pakistani family with autosomal recessive cone-rod dystrophy (arCRD). All affected individuals had night blindness, deterioration of central vision, photophobia, epiphora in bright light, and problems with color distinction. Fundoscopy revealed marked macular degeneration and attenuation of retinal vessels. Mild pigmentary changes were present in the periphery. METHODS: Genomic DNA was amplified across the polymorphic microsatellite poly-CA regions identified by markers. Alleles were assigned to individuals that allowed calculation of LOD scores using the Cyrillic (Cherwell Scientific, Oxford, UK) and MLINK (accessed from ftp://linkage. rockefeller.edu/softeware/linkage/) software programs. The cellular retinoic acid-binding protein 2 (CRABP2), cone transducin alpha-subunit (GNAT2), potassium inwardly rectifying channel, subfamily J, member 10 (KCNJ10), genes were analyzed by heteroduplex analysis and direct sequencing for mutations. RESULTS: A new locus for arCRD (CORD8) has been mapped to chromosome 1q12-q24. A maximum two-point LOD score of 4.22 was obtained with marker D1S2635 at recombination fraction of theta = 0.00. Two critical recombinations in the pedigree positioned this locus to a region flanked by markers D1S457 and D1S2681. A region of homozygosity was observed within the loci D1S442 and D1S2681, giving a probable critical disease interval of 21 cM. Mutation screening of the three candidate genes CRABP2, GNAT2, and KCNJ10 revealed no disease-associated mutations. CONCLUSIONS: The findings therefore suggest that this phenotype maps to a new locus and is due to an as yet uncharacterized gene within the 1q12-q24 chromosomal region.

Adolescent↗