A New Imaging Software To Evaluate The Centration Of Capsulorhexis And Intraocular Lens (IOL) After Cataract Surgery

Purpose: IOL centration and stability after cataract surgery is of high interest for cataract surgeons and IOL-producing companies. We present a new imaging software to evaluate the centration of the rhexis and the centration of the IOL after cataract surgery.Methods: We developed, in collaboration with the Biomedical Imaging Group (BIG), EPFL, Lausanne, a new working tool in order to assess precisely outcomes after IOL-implantation, such as ideal capsulorhexis and IOL-centration. The software is a plug-in of ImageJ, a general-purpose image processing and image-analysis package. The specifications of this software are: evaluation of the rhexis-centration and evaluation the position of the IOL in the posterior chamber. The end points are to analyze the quality of the centration of a rhexis after cataract surgery, the deformation of the rhexis with capsular bag retraction and the centration of the IOL after implantation.Results: This software delivers tools to interactively measure the distances between limbus, IOL and capsulorhexis and its changes over time. The user is invited to adjust nodes of three radial curves for the limbus, rhexis and the optic of the IOL. The radial distances of the curves are computed to evaluate the IOL implantation. The user is also able to define patterns for ideal capsulorhexis and optimal IOL-centration. We are going to present examples of calculations after cataract surgery.Conclusions: Evaluation of the centration of the rhexis and of the IOL after cataract surgery is an important end point for optimal IOL implantation after cataract surgery. Especially multifocal or accommodative lenses need a precise position in the bag with a good stability over time. This software is able to evaluate these parameters just after the surgery but also its changes over time. The results of these evaluations can lead to an optimizing of surgical procedures and materials.

A Missense Mutation in PRPF6 Causes Impairment of pre-mRNA Splicing and Autosomal-Dominant Retinitis Pigmentosa.

Retinitis pigmentosa (RP) is an inherited form of retinal degeneration that leads to progressive visual-field constriction and blindness. Although the disease manifests only in the retina, mutations in ubiquitously expressed genes associated with the tri-snRNP complex of the spliceosome have been identified in patients with dominantly inherited RP. We screened for mutations in PRPF6 (NM_012469.3), a gene on chromosome 20q13.33 encoding an essential protein for tri-snRNP assembly and stability, in 188 unrelated patients with autosomal-dominant RP and identified a missense mutation, c.2185C>T (p.Arg729Trp). This change affected a residue that is conserved from humans to yeast and cosegregated with the disease in the family in which it was identified. Lymphoblasts derived from patients with this mutation showed abnormal localization of endogenous PRPF6 within the nucleus. Specifically, this protein accumulated in the Cajal bodies, indicating a possible impairment in the tri-snRNP assembly or recycling. Expression of GFP-tagged PRPF6 in HeLa cells showed that this phenomenon depended exclusively on the mutated form of the protein. Furthermore, analysis of endogenous transcripts in cells from patients revealed intron retention for pre-mRNA bearing specific splicing signals, according to the same pattern displayed by lymphoblasts with mutations in other PRPF genes. Our results identify PRPF6 as the sixth gene involved in pre-mRNA splicing and dominant RP, corroborating the hypothesis that deficiencies in the spliceosome play an important role in the molecular pathology of this disease.

Familial evaluation in catecholaminergic polymorphic ventricular tachycardia: disease penetrance and expression in cardiac ryanodine receptor mutation-carrying relatives.

BACKGROUND: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome associated with mutations in the cardiac ryanodine receptor gene (Ryr2) in the majority of patients. Previous studies of CPVT patients mainly involved probands, so current insight into disease penetrance, expression, genotype-phenotype correlations, and arrhythmic event rates in relatives carrying the Ryr2 mutation is limited. METHODS AND RESULTS: One-hundred sixteen relatives carrying the Ryr2 mutation from 15 families who were identified by cascade screening of the Ryr2 mutation causing CPVT in the proband were clinically characterized, including 61 relatives from 1 family. Fifty-four of 108 antiarrhythmic drug-free relatives (50%) had a CPVT phenotype at the first cardiological examination, including 27 (25%) with nonsustained ventricular tachycardia. Relatives carrying a Ryr2 mutation in the C-terminal channel-forming domain showed an increased odds of nonsustained ventricular tachycardia (odds ratio, 4.1; 95% CI, 1.5-11.5; P=0.007, compared with N-terminal domain) compared with N-terminal domain. Sinus bradycardia was observed in 19% of relatives, whereas other supraventricular dysrhythmias were present in 16%. Ninety-eight (most actively treated) relatives (84%) were followed up for a median of 4.7 years (range, 0.3-19.0 years). During follow-up, 2 asymptomatic relatives experienced exercise-induced syncope. One relative was not being treated, whereas the other was noncompliant. None of the 116 relatives died of CPVT during a 6.7-year follow-up (range, 1.4-20.9 years). CONCLUSIONS: Relatives carrying an Ryr2 mutation show a marked phenotypic diversity. The vast majority do not have signs of supraventricular disease manifestations. Mutation location may be associated with severity of the phenotype. The arrhythmic event rate during follow-up was low.

Functional analysis of disease-causing NR2E3 mutations

Purpose:We analyzed the transcriptional activity of disease-causing NR2E3 mutant proteins in a heterologous system. NR2E3 belongs to the nuclear receptor superfamily of transcription factors, characterized by evolutionary-conserved DNA-binding (DBD) and ligand-binding (LBD) domains. NR2E3 acts in concert with the transcription factors CRX and NRL to repress cone-specific genes and activate rod-specific genes in rod photoreceptors. During development, NR2E3 is also required to suppress cone cell generation from retinal progenitor cells. In humans, mutations in NR2E3 have been associated with the recessively inherited enhanced short wavelength sensitive (S-) cone syndrome (ESCS), the Goldman-Favre syndrome, and, more recently, with autosomal dominant retinitis pigmentosa (adRP). Methods:The different NR2E3 mutants were generated by QuickChangeR mutagenesis and analyzed by transfection in heterologous HEK293T cells. Results:In transactivation assays in HEK293T cells, the adRP-linked p.G56R mutant protein exhibited a more severe effect both in activation of a rhodopsin promoter reporter construct and in repression of M-opsin promoter reporter construct, than the ESCS-linked R76Q, R76W, G88V, R97H, R104Q, R104W mutants of the DBD. In contrast, the ESCS-linked p.R311Q mutant of the LBD behaved like the NR2E3 wild-type protein in these assays. By co-expressing the corepressors atrophin-1 and -2, a differential repression of the M-opsin promoter was observed in presence of the p.R311Q, p.R385P and p.M407K. Interestingly, corepressor expression also affected the activity of CRX, but not NRL, in both rhodopsin and M-opsin transactivation assays. Conclusions:Taken together, these in vitro results suggest a distinct disease mechanism for the adRP-linked mutation, but open the possibility of different mechanisms for the development of ESCS that is clinically characterized by important phenotypic variations.

Exome sequencing identifies DYNC2H1 mutations as a common cause of asphyxiating thoracic dystrophy (Jeune syndrome) without major polydactyly, renal or retinal involvement.

BACKGROUND: Jeune asphyxiating thoracic dystrophy (JATD) is a rare, often lethal, recessively inherited chondrodysplasia characterised by shortened ribs and long bones, sometimes accompanied by polydactyly, and renal, liver and retinal disease. Mutations in intraflagellar transport (IFT) genes cause JATD, including the IFT dynein-2 motor subunit gene DYNC2H1. Genetic heterogeneity and the large DYNC2H1 gene size have hindered JATD genetic diagnosis. AIMS AND METHODS: To determine the contribution to JATD we screened DYNC2H1 in 71 JATD patients JATD patients combining SNP mapping, Sanger sequencing and exome sequencing. RESULTS AND CONCLUSIONS: We detected 34 DYNC2H1 mutations in 29/71 (41%) patients from 19/57 families (33%), showing it as a major cause of JATD especially in Northern European patients. This included 13 early protein termination mutations (nonsense/frameshift, deletion, splice site) but no patients carried these in combination, suggesting the human phenotype is at least partly hypomorphic. In addition, 21 missense mutations were distributed across DYNC2H1 and these showed some clustering to functional domains, especially the ATP motor domain. DYNC2H1 patients largely lacked significant extra-skeletal involvement, demonstrating an important genotype-phenotype correlation in JATD. Significant variability exists in the course and severity of the thoracic phenotype, both between affected siblings with identical DYNC2H1 alleles and among individuals with different alleles, which suggests the DYNC2H1 phenotype might be subject to modifier alleles, non-genetic or epigenetic factors. Assessment of fibroblasts from patients showed accumulation of anterograde IFT proteins in the ciliary tips, confirming defects similar to patients with other retrograde IFT machinery mutations, which may be of undervalued potential for diagnostic purposes.

La maladie des vibrations [The vibration syndrome].

The vibration syndrome is an often unrecognized occupational neurovascular disease with a prevalence of more than 70% in certain high-risk occupations. Early recognition is crucial because continued exposure to vibration can lead to irreversible ischemic injury and loss of digits. Digital ischemia due to the vibration syndrome may be due to a vasospastic phenomenon, an organic microangiopathy or arterial thrombosis. Demyelinating neuropathy and carpal tunnel syndrome are often associated. Many pathophysiological mechanisms are implicated: hyperactivity of the central sympathetic nervous system, release of plasma endothelin-1 and loss of calcitonin-gene-related-peptide vasoregulation. Investigation tests, treatment and the European Community Directive for the protection of workers are also presented.