Retinocytoma Undergoing Retinoblastoma Transformation in an Adult Patient.

We report a 46-year-old male patient with retinocytoma who presented at the age of 31 asymptomatically. An intraocular retinal mass was incidentally found in his right eye, when he underwent ophthalmological assessment for refractive surgery. This tumor consisted of a calcified sessile basis partially covered by a pedunculated salmon-pink growth. Initially, the tumor was diagnosed as a retinocytoma with clinical suspicion of malignant transformation into retinoblastoma and treated by four sessions of laser photocoagulation. Six and a half years later, the tumor relapsed, and he was treated with a Ruthenium plaque. Following brachytherapy, he had two episodes of right-sided vitreous hemorrhage that spontaneously cleared up, and the remaining finding in the vitreous cavity was interpreted as asteroid hyalosis. He underwent vitrectomy about five years following brachytherapy. The analysis of the vitreous material revealed the presence of inactive vitreous seeds composed of small round blue cells, compatible with a type 2 regression.

Retinoblastoma: From genes to patient care.

Retinoblastoma is the most common paediatric neoplasm of the retina, and one of the earliest model of cancer genetics since the identification of the master tumour suppressor gene RB1. Tumorigenesis has been shown to be driven by pathogenic variants of the RB1 locus, but also genomic and epigenomic alterations outside the locus. The increasing knowledge on this "mutational landscape" is used in current practice for precise genetic testing and counselling. Novel methods provide access to pre-therapeutic tumour DNA, by isolating cell-free DNA from aqueous humour or plasma. This is expected to facilitate assessment of the constitutional status of RB1, to provide an early risk stratification using molecular prognostic markers, to follow the response to the treatment in longitudinal studies, and to predict the response to targeted therapies. The aim of this review is to show how molecular genetics of retinoblastoma drives diagnosis, treatment, monitoring of the disease and surveillance of the patients and relatives. We first recap the current knowledge on retinoblastoma genetics and its use in every-day practice. We then focus on retinoblastoma subgrouping at the era of molecular biology, and the expected input of cell-free DNA in the field.

[Genotype-phenotype correlation in ten Tunisian families with non-syndromic retinitis pigmentosa]. / Corrélations phénotype-génotype de la rétinopathie pigmentaire non syndromique : à propos de dix familles tunisiennes.

PURPOSE: To evaluate the clinical phenotype of ten Tunisian families with non-syndromic retinitis pigmentosa (RP), to characterize genes and mutations causing these conditions, and to elaborate phenotype-genotype correlations. METHODS: Descriptive clinical genetic study of 114 individuals, of whom 27 are affected by non-syndromic RP. Ophthalmic examination and various visual tests were performed. DNA was analyzed using single nucleotide polymorphism, microsatellite genotyping and direct sequencing to determine the genes and mutations involved. RESULTS: We identified seven mutated genes: RPE65, RDH12, USHER 2A, PDE6a, PDE6b, CRB1, and NR2E3. Analysis of phenotype-genotype correlation indicated that some genes were associated with specific phenotypes. In RPE65 mutations, we found early onset dystrophy, nystagmus, keratoconus, white dot deposits in earlier stages and clumped pigment in later stages. The RDH12-associated phenotype (juvenile RP) showed severe and early-onset dystrophy, diffuse spicule pigmentation, macular edema and thickening, and tomographic re-organization of retinal layers. The CRB1 mutation was characterized by preserved para-arteriolar retinal pigment epithelium and no hemeralopia. CONCLUSION: RP is clinically and genetically heterogeneous. The two ultimate goals of research are to provide efficient clinical diagnostic of affected gene by phenotype-genotype correlation and to design novel treatment regimens. Our goal is to create a specific chip for our population, and then future research will focus on the identification of the remaining causal genes, the elucidation of the molecular mechanisms of disease in the retina and the development of gene therapy approaches.

Potential blindness in children of patients with hereditary bone disease.

Mono- and bi-allelic mutations in the low-density lipoprotein receptor related protein 5 (LRP5) may cause osteopetrosis, autosomal dominant and recessive exudative vitreoretinopathy, juvenile osteoporosis, or persistent hyperplastic primary vitreous (PHPV). We report on a child affected with PHPV and carrying compound mutations. The father carried the splice mutation and suffered from severe bone fragility since childhood. The mother carried the missense mutation without any clinical manifestations. The genetic diagnosis of their child allowed for appropriate treatment in the father and for the detection of osteopenia in the mother. Mono- and bi-allelic mutations in LRP5 may cause osteopetrosis, autosomal dominant and recessive exudative vitreoretinopathy, juvenile osteoporosis, or PHPV. PHPV is a component of persistent fetal vasculature of the eye, characterized by highly variable expressivity and resulting in a wide spectrum of anterior and/or posterior congenital developmental defects, which may lead to blindness. We evaluated a family diagnosed with PHPV in their only child. The child presented photophobia during the first 3 weeks of life, followed by leukocoria at 2 months of age. Molecular resequencing of NDP, FZD4, and LRP5 was performed in the child and segregation of the observed mutations in the parents. At presentation, fundus examination of the child showed a retrolental mass in the right eye. Ultrasonography revealed retinal detachment in both eyes. Thorough familial analysis revealed that the father suffered from many fractures since childhood without specific fragility bone diagnosis, treatment, or management. The mother was asymptomatic. Molecular analysis in the proband identified two mutations: a c.[2091+2T>C] splice mutation and c.[1682C>T] missense mutation. We report the case of a child affected with PHPV and carrying compound heterozygous LRP5 mutations. This genetic diagnosis allowed the clinical diagnosis of the bone problem to be made in the father, resulting in better management of the family. It also enabled preventive treatment to be prescribed for the mother and accurate genetic counseling to be provided.

Molecular Analysis of NOTCH2 in Patients with Primary Open-Angle Glaucoma.

BACKGROUND AND PURPOSE: Transgenic mice overexpressing Notch2 in the uvea exhibit a hyperplastic ciliary body leading to increased IOP and glaucoma. The aim of this study was to investigate the possible presence of NOTCH2 variants in patients with primary open-angle glaucoma (POAG). METHODS: We screened DNA samples from 130 patients with POAG for NOTCH2 variants by denaturing high-performance liquid chromatography after PCR amplification and validated our data by direct Sanger sequencing. RESULTS: No mutations were observed in the coding regions of NOTCH2 or in the splice sites. 19 known SNPs (single nucleotide polymorphisms) were detected. An SNP located in intron 24, c.[4005+45A>G], was seen in 28.5% of the patients (37/130 patients). As this SNP is reported to have a minor allele frequency of 7% in the 1000 genomes database, it could be associated with POAG. However, we evaluated its frequency in an ethnic-matched control group of 96 subjects unaffected by POAG and observed a frequency of 29%, indicating that it was not related to POAG. CONCLUSION: NOTCH2 seemed to be a good candidate for POAG as it is expressed in the anterior segment in the human eye. However, mutational analysis did not show any causative mutation. This study also shows that proper ethnic-matched control groups are essential in association studies and that values given in databases are sometimes misleading.

Cone-rod dystrophy caused by a novel homozygous RPE65 mutation in Leber congenital amaurosis.

BACKGROUND: The aim of this study was to describe an unexpected phenotype in a family with Leber congenital amaurosis (LCA) due to a retinal pigment epithelium-specific protein 65 kDa (RPE65) homozygous mutation. HISTORY AND SIGNS: We analyzed a family from Yemen in which 3 individuals were affected with LCA. Linkage analysis using markers flanking the known LCA genes was done, followed by direct sequencing of RPE65. THERAPY AND OUTCOME: Severe visual impairment and night blindness were observed during infancy. We observed photophobia only in the 8-year-old patient. The youngest affected had bilateral hyperopia of +3.50 and visual acuity of 1/60. The oldest two had visual acuity limited to hand movements in the right eye (OD) and counting fingers in the left eye (OS) for the oldest and of 5/60 OD, 6/60 OS for the other. They showed disc pallor, attenuated vessels, white flecks in the retina mid-periphery and bull's eye maculopathy. ERGs of the oldest child were completely unresponsive. Genomic sequencing identified a novel homozygous missense mutation, IVS2-3C>G, in the second RPE65 intron. CONCLUSIONS: We identified a novel LCA-related homozygous RPE65 mutation associated with a severe clinical presentation including an early and severe cone dysfunction. This is in contrast with the presentation associated with other RPE65 mutations predominantly causing rod-cone dystrophy with residual visual function.

Retinal dystrophy in the oculo-auricular syndrome due to HMX1 mutation.

PURPOSE: To report on the clinical and electrophysiological findings in a patient with oculo-auricular syndrome due to HMX1 mutation, with a follow-up of 12 years. BACKGROUND: Oculo-auricular syndrome (MIM: 612109) is a rare developmental recessive condition affecting the eye and external ear that results from a mutation in the HMX1 gene. Previously described ocular abnormalities include bilateral microcornea, posterior synechiae, cataract, chorioretinal colobomas and rod-cone dystrophy. METHODS: Retrospective chart review of an affected boy followed over a period of 12 years who had serial complete ophthalmologic examinations, fundus photographs, Goldmann perimetry and full-field electroretinograms (ERG). RESULTS: Initial ERG tracings revealed generalized rod more than cone dysfunction. Thereafter, a rapid deterioration in rod and cone function was detected on follow up ERGs. CONCLUSION: The retinal degeneration in the recessively inherited oculo-auricular syndrome is a progressive rod-cone dystrophy. Visual prognosis is guarded considering the progressive nature of the retinal dystrophy in early infancy.

[The IC3D classification of the corneal dystrophies]. / IC3D-Klassifikation von Hornhautdystrophien.

BACKGROUND: The recent availability of genetic analyses has demonstrated the shortcomings of the current phenotypic method of corneal dystrophy classification. Abnormalities in different genes can cause a single phenotype, whereas different defects in a single gene can cause different phenotypes. Some disorders termed corneal dystrophies do not appear to have a genetic basis. PURPOSE: The purpose of this study was to develop a new classification system for corneal dystrophies, integrating up-to-date information on phenotypic description, pathologic examination, and genetic analysis. METHODS: The International Committee for Classification of Corneal Dystrophies (IC3D) was created to devise a current and accurate nomenclature. RESULTS: This anatomic classification continues to organize dystrophies according to the level chiefly affected. Each dystrophy has a template summarizing genetic, clinical, and pathologic information. A category number from 1 through 4 is assigned, reflecting the level of evidence supporting the existence of a given dystrophy. The most defined dystrophies belong to category 1 (a well-defined corneal dystrophy in which a gene has been mapped and identified and specific mutations are known) and the least defined belong to category 4 (a suspected dystrophy where the clinical and genetic evidence is not yet convincing). The nomenclature may be updated over time as new information regarding the dystrophies becomes available. CONCLUSIONS: The IC3D Classification of Corneal Dystrophies is a new classification system that incorporates many aspects of the traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Standardized templates provide key information that includes a level of evidence for there being a corneal dystrophy. The system is user-friendly and upgradeable and can be retrieved on the website www.corneasociety.org/ic3d .

[New strategies in pediatric ophthalmic oncology]. / Nouvelles stratégies thérapeutiques en oncologie ophtalmo-pédiatrique.

Retinoblastoma represents 11% of all cancers during the first year of life. New drugs and focal treatments have been developed in order to avoid the side effects of systemic chemotherapy and external radiotherapy. New targeted and local administration strategies such as periocular chemotherapy (topotecan) or direct ophthalmic artery delivery (carboplatin), are already used today in selected resistant cases. Radiotherapy, presently indicated only as a second-line treatment, is also subject to new techniques, targeting tumors more closely to avoid involving healthy tissue and reduce the risk of radio-induced nonocular tumors. Stereotactic conformal radiotherapy and proton therapy may thus be included in the new range of treatment methods in retinoblastoma.

Genotype-phenotype correlation of age-related macular degeneration: influence of complement factor H polymorphism.

BACKGROUND/AIMS: Complement factor H (CFH) Y402H polymorphism shows a strong association with age-related macular degeneration (AMD). Although the phenotypic concordance of AMD has been shown in sibling/twin studies, little is known about the genotype-phenotype association. In this study, we investigated whether CFH Y402H is associated with early phenotypic features. METHODS: Statistical analysis was performed on 420 patients with AMD with complete clinical and genetic data (graded colour fundus photographs, according to the International Classification and Grading System for AMD and successful testing for CFH Y402H). RESULTS: In this Swiss population, an OR of 2.95 was confirmed for AMD in the presence of at least one risk C allele and OR of 9.05 for the CC homozygotes, corrected for age and sex. No difference was found between the AMD stages. Patients homozygous for the risk allele showed significant association with peripheral drusen (p = 0.028) and for central drusen location (p = 0.049). No trend was found for other drusen criteria (size, total surface, location nasal to disc) and for pigmentary changes. CONCLUSIONS: The CFH Y402H polymorphism showed a genotype-phenotype association for some drusen features. Additional genetic factors are likely to influence drusen phenotype.

Patient with Fanconi Syndrome (FS) and retinitis pigmentosa (RP) caused by a deletion and duplication of mitochondrial DNA (mtDNA).

BACKGROUND: We report a patient with a highly unusual presentation of a mitochondrial disorder. HISTORY AND SIGNS: An 8-year old girl presented with muscular cramps as well as height and weight deceleration. Investigations revealed lactic acidosis, electrolytic imbalance and urinary loss of glucose and electrolytes secondary to proximal renal tubulopathy consistent with Fanconi syndrome (FS). Ophthalmic examination revealed asymptomatic retinitis pigmentosa (RP) with no other ocular manifestations. A mitochondriopathy was suspected and genetic analysis performed. THERAPY AND OUTCOME: Southern blotting documented a heteroplasmic mutation of mtDNA with deletion/duplication. Three discrete mitochondrial genomes were detected: normal; deletion of 6.7 kb and a deletion/duplication consisting of 1 normal and 1 deleted genome. The relative proportions varied considerably between tissues. CONCLUSIONS: The association of FS and RP combines features of Kearns-Sayre syndrome and Pearson marrow-pancreas syndrome, without being typical of either. This highly unusual clinical presentation emphasises the need for systemic investigation of patients with FS and further underlines the importance of mtDNA analysis in patients with unexpected associations of affected tissues.

New VMD2 gene mutations identified in patients affected by Best vitelliform macular dystrophy.

PURPOSE: The mutations responsible for Best vitelliform macular dystrophy (BVMD) are found in a gene called VMD2. The VMD2 gene encodes a transmembrane protein named bestrophin-1 (hBest1) which is a Ca(2+)-sensitive chloride channel. This study was performed to identify disease-specific mutations in 27 patients with BVMD. Because this disease is characterised by an alteration in Cl(-) channel function, patch clamp analysis was used to test the hypothesis that one of the VMD2 mutated variants causes the disease. METHODS: Direct sequencing analysis of the 11 VMD2 exons was performed to detect new abnormal sequences. The mutant of hBest1 was expressed in HEK-293 cells and the associated Cl(-) current was examined using whole-cell patch clamp analysis. RESULTS: Six new VMD2 mutations were identified, located exclusively in exons four, six and eight. One of these mutations (Q293H) was particularly severe. Patch clamp analysis of human embryonic kidney cells expressing the Q293H mutant showed that this mutant channel is non-functional. Furthermore, the Q293H mutant inhibited the function of wild-type bestrophin-1 channels in a dominant negative manner. CONCLUSIONS: This study provides further support for the idea that mutations in VMD2 are a necessary factor for Best disease. However, because variable expressivity of VMD2 was observed in a family with the Q293H mutation, it is also clear that a disease-linked mutation in VMD2 is not sufficient to produce BVMD. The finding that the Q293H mutant does not form functional channels in the membrane could be explained either by disruption of channel conductance or gating mechanisms or by improper trafficking of the protein to the plasma membrane.

Diagnosis and current management of retinoblastoma.

Retinoblastoma represents the prototypic model for inherited cancers. The RB1 gene was the first tumor suppressor gene to be identified. It represents the most frequent primary eye cancer in children under 15 years old, habitually occurring in infancy, even in utero, but can be observed in older children or young adults. Many other retinal lesions may also simulate retinoblastoma. The two major presenting signs are leukocoria and strabismus, but other ocular or general signs may be observed. A highly malignant tumor, retinoblastoma can nowadays be cured. The heritable form, however, carries a high risk of second nonocular tumors. Treatment in the early stages of disease holds a good prognosis for survival and salvage of visual function. In very late stages, however, the prognosis for ocular function and even survival is jeopardized.

Pseudoxanthoma elasticum: evaluation of diagnostic criteria based on molecular data.

BACKGROUND: Pseudoxanthoma elasticum (PXE) is a genetic disorder due to mutations in the gene encoding the transmembrane transporter protein adenosine triphosphate binding cassette (ABC)-C6, resulting in calcification of elastic fibres in the skin, eyes and cardiovascular system. OBJECTIVES: To evaluate the diagnostic criteria for PXE based on molecular data. METHODS: Of 10 families with a positive history of PXE 142 subjects were investigated for clinical symptoms, histological findings and genetic haplotype analysis. RESULTS: Of these, 25 subjects were haplotypic homozygous for PXE and 23 had typical clinical and histopathological manifestations. Two of the 25 patients showed such marked solar elastosis and macular degeneration that PXE could not be confirmed clinically. Sixty-seven subjects were haplotypic heterozygous carriers and 50 were haplotypic homozygous unaffected. Of these 117 subjects, 116 showed no cutaneous or ophthalmological signs of PXE. In one of the 50 haplotypic homozygous unaffected patients important solar elastosis and scarring of the retina mimicked PXE lesions. Only four of the 67 haplotypic heterozygous carriers had biopsies of nonlesional skin; all were histopathologically normal. CONCLUSIONS: In our patients, PXE presents as an autosomal recessive genodermatosis. Correlation of haplotype and phenotype confirmed actual major diagnostic criteria. In patients with marked solar elastosis and/or severe macular degeneration clinical diagnosis can be impossible and molecular testing is needed to confirm the presence of PXE. To the best of our knowledge our large study compares for the first time clinical findings with molecular data.