Retinitis pigmentosa (RP) refers to a genetically heterogeneous group of progressive neurodegenerative diseases that result in dysfunction and/or death of rod and cone photoreceptors in the retina. So far, 18 genes have been identified for autosomal-dominant (ad) RP. Here, we describe an adRP locus (RP42) at chromosome 7p15 through linkage analysis in a six-generation Scandinavian family and identify a disease-causing mutation, c.449G-->A (p.S150N), in exon 6 of the KLHL7 gene. Mutation screening of KLHL7 in 502 retinopathy probands has revealed three different missense mutations in six independent families. KLHL7 is widely expressed, including expression in rod photoreceptors, and encodes a 75 kDa protein of the BTB-Kelch subfamily within the BTB superfamily. BTB-Kelch proteins have been implicated in ubiquitination through Cullin E3 ligases. Notably, all three putative disease-causing KLHL7 mutations are within a conserved BACK domain; homology modeling suggests that mutant amino acid side chains can potentially fill the cleft between two helices, thereby affecting the ubiquitination complexes. Mutations in an identical region of another BTB-Kelch protein, gigaxonin, have previously been associated with giant axonal neuropathy. Our studies suggest an additional role of the ubiquitin-proteasome protein-degradation pathway in maintaining neuronal health and in disease.

Background/aimsDuring the last decade, improved neonatal care has resulted in increased survival of the most immature infants and improved health of more mature infants. We hypothesise that this has affected incidence and treatment of retinopathy of prematurity (ROP), enabling guidelines for screening to be modified.MethodsIn Sweden, all infants with gestational age (GA) at birth ≤30 weeks are screened for ROP. Results are registered in a web-based register, Swedish National ROP Register, with a coverage rate of 97%. Incidence of ROP and frequency of treatment, aspects on natural course of ROP and number of examinations, are calculated in relation to GA at birth in infants born during 2008–2017.ResultsOf 7249 infants, 31.9% (2310) had ROP and 6.1% (440) were treated. No infant with GA 30 weeks was treated. Incidence of ROP remained similar, but frequency of treatment increased (p=0.023). Over time, GA and birth weight were reduced in infants with ROP and with treated ROP. In the most immature infants, postmenstrual age was lower and postnatal age was higher when any ROP and stage 3 ROP were first detected (p<0.001). At treatment, postmenstrual but not postnatal age of the infant was associated with GA (p<0.001). During the 10-year period, 46 038 examinations were performed.ConclusionModification of Swedish guidelines is proposed, including only infants with a GA of <30 weeks and postponing the first examination with 1 week in infants with GA 26–29 weeks. This would spare many infants from stressful examinations and reduce eye examinations with at least 20%.

ABSTRACT.Purpose: To evaluate (with three different electrophysiological methods) the residual retinal function in a selected group of patients with retinitis pigmentosa and remaining small central visual fields. Methods: Fourteen patients from several different genetic subgroups, who had been followed with visual acuity and visual field testing for periods up to 32 years, were examined. Ophthalmological examination included full-field electroretinography (ERG), multifocal electroretinography (mfERG) and multifocal visual evoked potential (mfVEP). Results: The ERGs were severely reduced in all patients. The mfERGs demonstrated the residual central retinal function in five of the patients. The mfVEPs showed measurable amplitudes centrally in most of the patients. The follow-up examinations demonstrated the slowly progressive course of the disease with preservation or only slight further loss of visual fields over a period of 7-32 years. Conclusion: Patients with retinitis pigmentosa may not always follow the typical natural course with progressive loss of visual fields, which may in some patients remain unaffected over several decades. Multifocal ERG and mfVEP may be clinically useful for evaluating remaining visual function in these patients.

This study demonstrates changes in histopathology caused by vigabatrin in an animal model, which has not been reported previously. We have found that vigabatrin orally administrated to rabbits does not affect rod function but may reduce cone function in the full-field electroretinogram, which is similar to the previously reported vigabatrin effect on the human ERG. The results indicate that vigabatrin may damage or influence, at least one cell type in the rabbit retina.