title: Two novel PRP31 premessenger ribonucleic acid processing factor 31 homolog mutations including a complex insertion-deletion identified in Chinese families with retinitis pigmentosa.
abstract: OBJECTIVE
  To identify the causative mutations in two Chinese families with retinitis pigmentosa (RP), and to describe the associated phenotype.
  
  
  METHODS
  Individuals from two unrelated families underwent full ophthalmic examinations. After informed consent was obtained, genomic DNA was extracted from the venous blood of all participants. Linkage analysis was performed on the known genetic loci for autosomal dominant retinitis pigmentosa with a panel of polymorphic markers in the two families, and then all coding exons of the PRP31 premessenger ribonucleic acid processing factor 31 homolog (PRPF31) gene were screened for mutations with direct sequencing of PCR-amplified DNA fragments. Allele-specific PCR was used to validate a substitution in all available family members and 100 normal controls. A large deletion was detected with real-time quantitative PCR (RQ-PCR) using a panel of primers from regions around the PRPF31 gene. Long-range PCR, followed by DNA sequencing, was used to define the breakpoints.
  
  
  RESULTS
  Clinical examination and pedigree analysis revealed two four-generation families (RP24 and RP106) with autosomal dominant retinitis pigmentosa. A significant two-point linkage odd disequilibrium score was generated at marker D19S926 (Zmax=3.55, θ=0) for family RP24 and D19S571 (Zmax=3.21, θ=0) for family RP106, and further linkage and haplotype studies confined the disease locus to chromosome 19q13.42 where the PRPF31 gene is located. Mutation screening of the PRPF31 gene revealed a novel deletion c.1215delG (p.G405fs+7X) in family RP106. The deletion cosegregated with the family's disease phenotype, but was not found in 100 normal controls. No disease-causing mutation was detected in family RP24 with PCR-based sequencing analysis. RQ-PCR and long-range PCR analysis revealed a complex insertion-deletion (indel) in the patients of family RP24. The deletion is more than 19 kb and encompasses part of the PRPF31 gene (exons 1-3), together with three adjacent genes.
  
  
  CONCLUSIONS
  Our results further confirmed that haploinsufficiency is the main mechanism for RP11 and that genomic arrangements may be prevalent in PRPF31 mutations.
authors: Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab. Beijing, China.
authors: Bing
authors: B
authors: Dong
authors: Jieqiong
authors: J
authors: Chen
authors: Xiaohui
authors: X
authors: Zhang
authors: Zhe
authors: Z
authors: Pan
authors: Fengge
authors: F
authors: Bai
authors: Yang
authors: Y
authors: Li
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D044466:Asian People; D001483:Base Sequence; D016022:Case-Control Studies; D002648:Child; D002888:Chromosomes, Human, Pair 19 / Q000737:chemistry; D005091:Exons; D005136:Eye Proteins / Q000235:genetics*; D005260:Female; D005799:Genes, Dominant; D056426:Genetic Loci; D006801:Humans; D054643:INDEL Mutation; D015810:Linkage Disequilibrium; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D010375:Pedigree; D012174:Retinitis Pigmentosa / Q000208:ethnology / Q000235:genetics* / Q000473:pathology; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion
chemical_list: D005136:Eye Proteins; C454222:PRPF31 protein, human