Homozygosity Mapping and Targeted Sanger Sequencing Identifies Three Novel CRB1 [Crumbs homologue 1] Mutations in Iranian Retinal Degeneration Families

Background: Inherited retinal diseases [IRDs] are a group of genetic disorders with high degrees of clinical, genetic and allelic heterogeneity. IRDs generally show progressive retinal cell death resulting in gradual vision loss

IRDs constitute a broad spectrum of disorders including retinitis pigmentosa and Leber congenital amaurosis. In this study, we performed genotyping studies to identify the underlying mutations in three Iranian families

Methods: Having employed homozygosity mapping and Sanger sequencing, we identified the underlying mutations in the crumbs homologue 1 gene. The CRB1 protein is a part of a macromolecular complex with a vital role in retinal cell polarity, morphogenesis, and maintenance

Results: We identified a novel homozygous variant [c.1053-1061del; p.Gly352-Cys354del] in one family, a combination of a novel [c.2086T>C; p.Cys696Arg] and a known variant [c.2234C>T, p.Thr745Met] in another family and a homozygous novel variant [c.3090T>A; p.Asn!030Lys] in a third family

Conclusion: This study shows that mutations in CRB1 are relatively common in Iranian non-syndromic IRD patients

Oscillatory potentials in diabetic retina without retinopath

To study recordings of oscillatory potentials [OPs] of the electroretinogram [ERG] in diabetic eyes that have no visible fundus alterations to ascertain whether changes in sensitivity are evident when compared with recordings from age-matched controls. OPs of the ERG were measured from 68 eyes of 34 patients with diabetes without retinopathy and from 30 eyes of 15 normal subjects. A reduction in the amplitude of each oscillatory potential, as well as delayed implicit time of each oscillatory potential peak could be found in diabetic patients without retinopathy although not all significant. Decrease in the amplitude of OP1 and summed OP [OP-sum] and also delayed the implicit time of OP1 were seen between diabetic patients with no observable diabetic retinopathy. Patients with diabetes without retinopathy show prolonged latencies in OPs recordings and decreased in amplitudes of OP-1 and OP-sum. This indicates an alteration in inner retinal sensitivity or ischemic change of overall retinal layer that can be explained by an impaired rod-cone interaction

Comparison of the effect of adjuvant 5-fluorouracil, low molecular weight heparin and daunomycin in combination with triamcinolone during vitrectomy in advanced retinal detachment

To compare the success rate of adjunctive 5-fluorouracil [5-FU] and low molecular weight heparin [LMWH], and daunomycin in combination with triamcinolone during vitrectomy in eyes with retinal detachment [RD] and proliferative vitreoretinopathy [PVR]. In this prospective randomized clinical trial, 69 eyes from 69 patients with RD and PVR [grade B or C] randomized to 3 groups. Group 1: received 5-FU and LMWH [200 microgram/ml 5-FU and 5 IU/ml LMWH, Fragmin]; group 2: received daunomycin [0.5 mg] in 500 cc infusion fluid; and group 3: control group. In all patients, 0.1 cc intravitreal triamcinolone was used during vitrectomy. The patients visited on day 1, week 1, month 1, 3 and 6. Best corrected visual acuity [BCVA] and retinal status compared in the 3 groups. Complete data were available for 60 out of 69 patients. Thirty five patients [58.3%] were male and 25 patients [41.7%] were female. The patient age range was 19-84 years and the mean age was 49. The groups did not have significant difference in age, sex, duration of detachment, severity of PVR, preoperative visual acuity [V/A], lens status, type of tamponade and encircling band and buckle. Postoperative V/A and retina status also was the same in the 3 groups. Perioperative infusion of 5-FU, LMWH and daunomycin does not significantly increase the success rate of patients with RD and PVR comparing to control group. Although visual acuity improvement and retina reattachment rate in group 1 and 2 were better than control group, but statistical analysis failed to show significant difference between the 3 groups