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The eye
Published in Angus Clarke, Alex Murray, Julian Sampson, Harper's Practical Genetic Counselling, 2019
Retinitis pigmentosa (RP) is the most common of the retinal degenerations. This group of disorders may follow all three main modes of Mendelian inheritance, autosomal recessive forms being the most common (about 50%), with autosomal dominant inheritance accounting for around 25% of families. X-linked cases account for around 15% of the total, but for about 50% of isolated male cases. A few cases arise as a result of digenic inheritance (heterozygosity at two different loci). Marked variation in course occurs in different families, suggesting further heterogeneity. At least 75 loci have been implicated in non-syndromic RP, although most of these are only rare causes. Although there is some variation between geographical areas, variants in RHO, PRPF31 and PRPH2 are the most common forms of autosomal dominant RP, and variants in EYS, USH2A, CRB1 and CERKL are the most prevalent forms of autosomal recessive RP. Most cases of X-linked RP result from variants in RPGR, with fewer from variants in RP2.
Disease progression of retinitis pigmentosa caused by PRPF31 variants in a Nordic population: a retrospective study with up to 36 years follow-up
Published in Ophthalmic Genetics, 2023
Kristian Lisbjerg, Mette Bertelsen, Julie Lyng Forman, Karen Grønskov, Josephine Prener Holtan, Line Kessel
Heterozygous pathogenic variants in PRPF31 can cause autosomal dominant RP and are reported to account for approximately 5–10% of all dominant RP cases (5). PRPF31 is located on chromosome 19 and encodes the PRPF31 protein which is a pre-mRNA splicing factor involved in coupling of the spliceosome (6). The spliceosome is a vital part of the protein synthesis and pathogenic variants in PRPF31 cause less efficient splicing and thus an impaired protein synthesis (7). The disease mechanism is haploinsufficiency (8). PRPF31 is ubiquitously expressed in all tissues in the body, but only retina-specific disease has been described, most likely due to high splicing demands in the retina (7). Cases of non-penetrance with asymptomatic carriers are well described in PRPF31-related retinitis pigmentosa, known as retinitis pigmentosa type-11 (RP11) (9).
Exploring microperimetry and autofluorescence endpoints for monitoring disease progression in PRPF31-associated retinopathy
Published in Ophthalmic Genetics, 2021
Danial Roshandel, Jennifer A. Thompson, Jason Charng, Dan Zhang, Enid Chelva, Sukanya Arunachalam, Mary S. Attia, Tina M. Lamey, Terri L. McLaren, John N. De Roach, David A. Mackey, Steve D. Wilton, Sue Fletcher, Samuel McLenachan, Fred K. Chen
Rapid advances in the treatment of retinitis pigmentosa (RP) have prompted an urgent need for feasible and reliable efficacy outcome measures for use in RP clinical trials (1). Whilst cross-sectional studies may provide data on the feasibility of various clinical tests in RP, a natural history study is necessary to identify the most suitable trial endpoints at various stages of the disease. It is widely recognised that there is significant variation in the natural history between various genetic causes of RP. More recent studies have also shown significant inter- and intra-familial phenotypic variations even amongst patients with the same mutation (2–4). The precursor mRNA processing factor 31 (PRPF31)-associated RP (also known as RP11) is one example of this variability in phenotype (5,6).