| 1. |
- Friedman, James S., et al.
(author)
-
Mutations in a BTB-Kelch Protein, KLHL7, Cause Autosomal-Dominant Retinitis Pigmentosa
- 2009
-
In: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 84:6, s. 792-800
-
Journal article (peer-reviewed)abstract
- 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.
|
|
| 2. |
|
|
| 3. |
- Gränse, Lotta
(author)
-
Evaluation of the visual pathway with ERG, mfERG and mfVEP in inherited eye disorders
- 2006
-
Doctoral thesis (other academic/artistic)abstract
- This thesis will describe the clinical phenotypes, with emphasis on electrophysiology, in patients with different hereditary eye diseases and to further evaluate and modify the mfVEP technique for clinical use. Bothnia Dystrophy is a tapetoretinal disorder with a mutation in the RLBP1 gene. Early in the disease the fundus may have a normal appearance. The full-field ERG demonstrates an absence of the rod response but normal amplitudes for the cones. However, after prolonged dark adaptation the rods recover completely. MfERG can be used for objective documentation of the disturbed macular function. Patients with retinitis pigmentosa may not always follow the typical natural course of the disorder with progressive loss of the central visual fields, which may in some patients remain unaffected for several decades. MfERG and mfVEP may be of clinical use in evaluating remaining visual function in these patients. Patients with dominant optic atrophy and a known mutation in the OPA-1 gene have a very variable clinical phenotype. MfVEP and ocular blood flow measurements are two new methods for improved identification and characterization of this disorder. A patient with a known mutation for Leber`s hereditary optic neuropathy (LHON) was followed during the acute stage of the disease with mfVEP, demonstrating a correlation to the progression of the disease. The mfVEP may be of clinical value as an objective method for monitoring the course of this disease. MfVEP demonstrates the cortical response corresponding to the central visual field. An improvement for the clinical value of the method was the use of an IR-camera for both stimulation and for controlling the fixation. By introducing a two channel system it was possible to describe the uncrossed/crossed visual pathways and analyze inter-ocular differences.
|
|
| 4. |
- Hugosson, Therése, et al.
(author)
-
Macular Dysfunction and Morphology in Spinocerebellar Ataxia Type 7 (SCA 7)
- 2009
-
In: Ophthalmic Genetics. - : Informa UK Limited. - 1744-5094 .- 1381-6810. ; 30:1, s. 1-6
-
Journal article (peer-reviewed)abstract
- Purpose: To characterize the clinical phenotype regarding retinal function and macular appearance in patients with spinocerebellar ataxia type 7 (SCA 7), with an emphasis on electrophysiological findings. Methods: Three patients from two Swedish families were given an ophthalmological examination including visual acuity, fundus inspection, Farnsworth's color vision test, Goldmann perimetry, full-field electroretinography (full-field ERG), multifocal electroretinography (mfERG) and optical coherence tomography (OCT). DNA was analyzed with polymerase chain reaction for CAG trinucleotide expansion repeats in the SCA 7 gene. Results: Molecular analysis demonstrated abnormally expanded CAG repeats in the gene for SCA 7, which encodes the protein ataxin-7, thus confirming the diagnosis SCA 7. In the oldest patient very discreet pigmentary changes in the maculae were found, but with that exception the patients had a normal ophthalmoscopic fundus appearance and OCT demonstrated only minor changes. MfERG indicated predominantly central involvement, especially in the early disease stages, which in pace with disease progression extended from the center to the more peripheral areas. Full-field ERG in the oldest patient demonstrated bilaterally distinctly prolonged 30-Hz flicker implicit time, verifying widespread cone photoreceptor degeneration. Conclusions: The patients with genetically confirmed SCA 7 presented an early macular dysfunction, preceding any signs of abnormalities in fundus appearance. According to the electrophysiological findings the primary dysfunction involves the cone photoreceptors in the foveal region, however in an older patient involvement of cone photoreceptors throughout the retina was verified. This is in accordance with the theory that ataxin-7 interacts with CRX transcription, since it is known that mutations in the CRX gene cause cone-rod dystrophy.
|
|
