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- Areblom, Maria, et al.
(författare)
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A Description of the Yield of Genetic Reinvestigation in Patients with Inherited Retinal Dystrophies and Previous Inconclusive Genetic Testing
- 2023
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Ingår i: Genes. - 2073-4425. ; 14:7
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Tidskriftsartikel (refereegranskat)abstract
- In the present era of evolving gene-based therapies for inherited retinal dystrophies (IRDs), it has become increasingly important to verify the genotype in every case, to identify all subjects eligible for treatment. Moreover, combined insight concerning phenotypes and genotypes is crucial for improved understanding of thevisual impairment, prognosis, and inheritance. The objective of this study was to investigate to what extent renewed comprehensive genetic testing of patients diagnosed with IRD but with previously inconclusive DNA test results can verify the genotype, if confirmation of the genotype has an impact on the understanding of the clinical picture, and, to describe the genetic spectrum encountered in a Swedish IRD cohort. The study included 279 patients from the retinitis pigmentosa research registry (comprising diagnosis within the whole IRD spectrum), hosted at the Department of Ophthalmology, Skåne University hospital, Sweden. The phenotypes had already been evaluated with electrophysiology and other clinical tests, e.g., visual acuity, Goldmann perimetry, and fundus imaging at the first visit, sometime between 1988–2015 and the previous—in many cases, multiple—genetic testing, performed between 1995 and 2020 had been inconclusive. All patients were aged 0–25 years at the time of their first visit. Renewed genetic testing was performed using a next generation sequencing (NGS) IRD panel including 322 genes (Blueprint Genetics). Class 5 and 4 variants, according to ACMG guidelines, were considered pathogenic. Of the 279 samples tested, a confirmed genotype was determined in 182 (65%). The cohort was genetically heterogenous, including 65 different genes. The most prevailing were ABCA4 (16.5%), RPGR (6%), CEP290 (6%), and RS1 (5.5%). Other prevalent genes were CACNA1F (3%), PROM1 (3%), CHM (3%), and NYX (3%). In 7% of the patients there was a discrepancy between the diagnosis made based on phenotypical or genotypical findings alone. To conclude, repeated DNA-analysis was beneficial also in previously tested patients and improved our ability to verify the genotype–phenotype association increasing the understanding of how visual impairment manifests, prognosis, and the inheritance pattern. Moreover, repeated testing using a widely available method could identify additional patients eligible for future gene-based therapies.
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| 2. |
- Friedman, James S., et al.
(författare)
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Mutations in a BTB-Kelch Protein, KLHL7, Cause Autosomal-Dominant Retinitis Pigmentosa
- 2009
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297. ; 84:6, s. 792-800
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Tidskriftsartikel (refereegranskat)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.
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| 3. |
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| 4. |
- Gränse, Lotta, et al.
(författare)
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Electrophysiologic findings in two young patients with Bothnia dystrophy and a mutation in the RLBP1 gene
- 2001
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Ingår i: Ophthalmic Genetics. - : Swets & Zeitlinger Publishers. - 1744-5094 .- 1381-6810. ; 22:2, s. 97-105
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To characterize the clinical phenotype, with emphasis on electrophysiology, of two children with suspected Bothnia dystrophy. Methods: Two unrelated affected patients, 10 and 11 years old, were studied. Ophthalmological examination included testing of visual acuity, fundus inspection and fundus photography, kinetic perimetry, full-field electroretinogram (ERG), and multifocal ERG. The presence of a mutation in exon 7 of the RLBP1 gene was investigated by DNA sequencing. Results: Both patients were homozygous for the Arg234Trp-causing mutation in the RLBP1 gene, but the resulting disease phenotype appeared to vary somewhat between them. Visual acuity was moderately reduced in one patient and normal in the other. Fundus inspection at this age revealed no pathology in either patient and there were no signs of retinitis punctata albescens, which has been described previously as a frequent clinical feature of Bothnia dystrophy. The result of kinetic perimetry was normal. The final rod threshold was moderately elevated. Full-field ERG demonstrated the uncommon combination of absent rod response and normal cone response after 40 minutes of dark adaptation. However, after prolonged dark adaptation (20-24 h), both the rod response and the dark adaptation threshold became normal. Multifocal ERG was performed in one of the patients (the one with normal visual acuity and normal fundus appearance) and showed a reduced cone response in the central region of the tested area. There was no improvement of the multifocal ERG result after 20-24 h of dark adaptation. Conclusion: Patients with mutations in the RLBP1 gene (Arg234Trp) may have a normal fundus appearance early in the disease course. Multifocal ERG can be used for the objective documentation of the disturbed macular function, especially when the patient's visual acuity and fundus appearance are normal. The rod response is absent in the electroretinogram; however, after prolonged dark adaptation (20-24 hours), the rods recover completely. The central cones do not seem to recover.
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| 5. |
- Gränse, Lotta, et al.
(författare)
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Electrophysiology and ocular blood flow in a family with dominant optic nerve atrophy and a mutation in the OPA1 gene
- 2003
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Ingår i: Ophthalmic Genetics. - : Swets & Zeitlinger Publishers. - 1744-5094 .- 1381-6810. ; 24:4, s. 233-245
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To characterize the clinical phenotype, with emphasis on electrophysiology and blood flow measurements, of a family with dominant optic nerve atrophy and an identified mutation in the OPA1 gene. METHODS: Seven family members were examined. Ophthalmological evaluation included testing of visual acuity, ophthalmolscopy, kinetic perimetry, color vision testing, full-field electroretinography (ERG), multifocal electroretinography (MERG), and multifocal visual evoked potential (MVEP). Retrobulbar arterial blood flow and retinal capillary perfusion was measured in three patients using scanning laser Doppler flowmetry (SLDF) and color Doppler imaging techniques. PCR-SSCP and DNA sequencing determined the presence of a mutation in exon 18 of the OPA1 gene. RESULTS: The clinical characteristics varied considerably in the family. The ERG and the MERG demonstrated normal retinal function, while the MVEP was abnormal in all examined patients. Retinal and optic nerve head capillary perfusion was significantly decreased in the three patients examined with SLDF. Retrobulbar blood flow velocities were significantly decreased in the central retinal and ophthalmic arteries. In all seven examined subjects, a microdeletion (1756-1767del(12 bp)) in the OPA1 gene was identified. CONCLUSION: Patients with a mutation in the OPA1 gene have a very variable phenotype. MVEP and blood flow measurements are two new objective methods for an easier detection of this specific genetic optic nerve atrophy.
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| 6. |
- Gränse, Lotta
(författare)
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Evaluation of the visual pathway with ERG, mfERG and mfVEP in inherited eye disorders
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)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.
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| 10. |
- Hellström, Ann, 1959, et al.
(författare)
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Association of Docosahexaenoic Acid and Arachidonic Acid Serum Levels With Retinopathy of Prematurity in Preterm Infants
- 2021
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Ingår i: Jama Network Open. - : American Medical Association (AMA). - 2574-3805. ; 4:10
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Supplementing preterm infants with long-chain polyunsaturated fatty acids (LC-PUFA) has been inconsistent in reducing the severity and incidence of retinopathy of prematurity (ROP). Furthermore, few studies have measured the long-term serum lipid levels after supplementation. OBJECTIVE To assess whether ROP severity is associated with serum levels of LC-PUFA, especially docosahexaenoic acid (DHA) and arachidonic acid (AA), during the first 28 postnatal days. DESIGN, SETTING, AND PARTICIPANTS This cohort study analyzed the Mega Donna Mega study, a randomized clinical trial that provided enteral fatty acid supplementation at 3 neonatal intensive care units in Sweden. Infants included in this cohort study were born at a gestational age of less than 28 weeks between December 20, 2016, and August 6, 2019. MAIN OUTCOMES AND MEASURES Severity of ROP was classified as no ROP, mild or moderate ROP (stage 1-2), or severe ROP (stage 3 and type 1). Serum phospholipid fatty acids were measured through gas chromatography-mass spectrometry. Ordinal logistic regression, with a description of unadjusted odds ratio (OR) as well as gestational age- and birth weight-adjusted ORs and 95% CIs, was used. Areas under the curve were used to calculate mean daily levels of fatty acids during postnatal days 1 to 28. Blood samples were obtained at the postnatal ages of 1, 3, 7, 14, and 28 days. RESULTS A total of 175 infants were included in analysis. Of these infants, 99 were boys (56.6%); the median (IQR) gestational age was 25 weeks 5 days (24 weeks 3 days to 26 weeks 6 days), and the median (IQR) birth weight was 785 (650-945) grams. A higher DHA proportion was seen in infants with no ROP compared with those with mild or moderate ROP or severe ROP (OR per 0.5-molar percentage increase, 0.49 [95% CI, 0.36-0.68]; gestational age- and birth weight-adjusted OR, 0.66 [95% CI, 0.46-0.93]). The corresponding adjusted OR for AA levels per 1-molar percentage increase was 0.83 (95% CI, 0.66-1.05). The association between DHA levels and ROP severity appeared only in infants with sufficient AA levels, suggesting that a mean daily minimum level of 7.8 to 8.3 molar percentage of AA was necessary for a detectable association between DHA level and less severe ROP. CONCLUSIONS AND RELEVANCE This cohort study found that higher mean daily serum levels of DHA during the first 28 postnatal days were associated with less severe ROP even after adjustment for known risk factors, but only in infants with sufficiently high AA levels. Further studies are needed to identify LC-PUFA supplementation strategies that may prevent ROP and other morbidities.
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