JAMA Ophthalmology: Retinal/Chorioretinal Disorders Topic Collection

Phenotypic Conservation in Patients With X-Linked Retinitis Pigmentosa Caused by RPGR Mutations Phenotypic Conservation in Patients With XLRP

Zahid S, Khan N, Branham K, et al. — Thu, 16 May 2013 00:00:00 GMT

Importance

For patients with X-linked retinitis pigmentosa and clinicians alike, phenotypic variability can be challenging because it complicates counseling regarding patients' likely visual prognosis.

Objective

To evaluate the clinical findings from patients with X-linked retinitis pigmentosa with 13 distinct RPGR mutations and assess for phenotypic concordance or variability.

Design

Retrospective medical record review of data collected from 1985 to 2011.

Setting

Kellogg Eye Center, University of Michigan.

Patients

A total of 42 patients with X-linked retinitis pigmentosa with mutations in RPGR. Age at first visit ranged from 4 to 53 years, with follow-up ranging from 1 to 11 visits (median follow-up time, 5.5 years; range, 1.4-32.7 years, for 23 patients with >1 visit).

Main Outcomes and Measures

Clinical data assessed for concordance included visual acuity (VA), Goldmann visual fields (GVFs), and full-field electroretinography (ERG). Electroretinography phenotype (cone-rod vs rod-cone dysfunction) was defined by the extent of photopic vs scotopic abnormality. Qualitative GVF phenotype was determined by the GVF pattern, where central or peripheral loss suggested cone or rod dysfunction, respectively. Goldmann visual fields were also quantified and compared among patients.

Results

Each mutation was detected in 2 or more related or unrelated patients. Five mutations in 11 patients displayed strong concordance of VA, while 4 mutations in 16 patients revealed moderate concordance of VA. A definitive cone-rod or rod-cone ERG pattern consistent among patients was found in 6 of 13 mutations (46.2%); the remaining mutations were characterized by patients demonstrating both phenotypes or who had limited data or nonrecordable ERG values. Concordant GVF phenotypes (7 rod-cone pattern vs 4 cone-rod pattern) were seen in 11 of 13 mutations (84.6%). All 6 mutations displaying a constant ERG pattern within the mutation group revealed a GVF phenotype consistent with the ERG findings.

Conclusions and Relevance

While VA and ERG phenotypes are concordant in only some patients carrying identical mutations, assessment of GVF phenotypes revealed stronger phenotypic conservation. Phenotypic concordance is important for establishing proper counseling of patients diagnosed as having X-linked retinitis pigmentosa, as well as for establishing accurate patient selection and efficacy monitoring in therapeutic trials.

Intrachoroidal Cavitation in North Carolina Macular Dystrophy

Schoenberger SD, Agarwal A. — Thu, 16 May 2013 00:00:00 GMT

North Carolina macular dystrophy (NCMD) is an autosomal dominantly inherited condition with 3 phenotypic grades. Grade 1 has yellow or white drusenlike deposits. Grade 2 features confluent drusen, pigmentary changes, retinal pigment epithelial (RPE) atrophy, or subretinal scarring. Grade 3 is described as a macular staphyloma, coloboma, or caldera with hyperpigmentation and subretinal fibrosis. Different grades and expressivity may be seen within one family, and the etiology is unknown.

Paul A. Cibis, MD A Pioneer of Modern Vitreoretinal Surgery Paul A. Cibis, MD

Feibel RM, Blodi CF. — Thu, 16 May 2013 00:00:00 GMT

Paul Anton Cibis (1911-1965) was one of the pioneers of modern vitreoretinal surgery. He reasoned that the pathology of complex retinal detachments was intravitreal fibrosis and concluded that the optimum surgery was the injection of liquid silicone oil into the vitreous cavity to dissect fibrous membranes from the retinal surface and use the silicone for retinal tamponade. Prior to the invention of pars plana vitrectomy, such surgery was innovative, even daring. These surgical techniques were an important advance in directly operating on the vitreous in retinal detachment surgery. However, Cibis' contributions to vitreoretinal surgery only occupied the last 10 years of his tragically short life. Prior to his practice in retinal surgery, he made contributions to basic research in physiologic optics, local retinal adaptation, and the effect of ionizing radiation and atomic energy on the globe.