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. 1998 Mar;62(3):585–592. doi: 10.1086/301756

Splice-site mutations: a novel genetic mechanism of Crigler-Najjar syndrome type 1.

S Gantla 1, C T Bakker 1, B Deocharan 1, N R Thummala 1, J Zweiner 1, M Sinaasappel 1, J Roy Chowdhury 1, P J Bosma 1, N Roy Chowdhury 1
PMCID: PMC1376950  PMID: 9497253

Abstract

Crigler-Najjar syndrome type 1 (CN-1) is a recessively inherited, potentially lethal disorder characterized by severe unconjugated hyperbilirubinemia resulting from deficiency of the hepatic enzyme bilirubin-UDP-glucuronosyltransferase. In all CN-1 patients studied, structural mutations in one of the five exons of the gene (UGT1A1) encoding the uridinediphosphoglucuronate glucuronosyltransferase (UGT) isoform bilirubin-UGT1 were implicated in the absence or inactivation of the enzyme. We report two patients in whom CN-1 is caused, instead, by mutations in the noncoding intronic region of the UGT1A1 gene. One patient (A) was homozygous for a G-->C mutation at the splice-donor site in the intron, between exon 1 and exon 2. The other patient (B) was heterozygous for an A-->G shift at the splice-acceptor site in intron 3, and in the second allele a premature translation-termination codon in exon 1 was identified. Bilirubin-UGT1 mRNA is difficult to obtain, since it is expressed in the liver only. To determine the effects of these splice-junction mutations, we amplified genomic DNA of the relevant splice junctions. The amplicons were expressed in COS-7 cells, and the expressed mRNAs were analyzed. In both cases, splice-site mutations led to the use of cryptic splice sites, with consequent deletions in the processed mRNA. This is the first report of intronic mutations causing CN-1 and of the determination of the consequences of these mutations on mRNA structure, by ex vivo expression.

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Selected References

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  1. Arias I. M., Gartner L. M., Cohen M., Ezzer J. B., Levi A. J. Chronic nonhemolytic unconjugated hyperbilirubinemia with glucuronyl transferase deficiency. Clinical, biochemical, pharmacologic and genetic evidence for heterogeneity. Am J Med. 1969 Sep;47(3):395–409. doi: 10.1016/0002-9343(69)90224-1. [DOI] [PubMed] [Google Scholar]
  2. Bosma P. J., Chowdhury J. R., Huang T. J., Lahiri P., Elferink R. P., Van Es H. H., Lederstein M., Whitington P. F., Jansen P. L., Chowdhury N. R. Mechanisms of inherited deficiencies of multiple UDP-glucuronosyltransferase isoforms in two patients with Crigler-Najjar syndrome, type I. FASEB J. 1992 Jul;6(10):2859–2863. doi: 10.1096/fasebj.6.10.1634050. [DOI] [PubMed] [Google Scholar]
  3. Bosma P. J., Chowdhury N. R., Goldhoorn B. G., Hofker M. H., Oude Elferink R. P., Jansen P. L., Chowdhury J. R. Sequence of exons and the flanking regions of human bilirubin-UDP-glucuronosyltransferase gene complex and identification of a genetic mutation in a patient with Crigler-Najjar syndrome, type I. Hepatology. 1992 May;15(5):941–947. doi: 10.1002/hep.1840150531. [DOI] [PubMed] [Google Scholar]
  4. Bosma P. J., Seppen J., Goldhoorn B., Bakker C., Oude Elferink R. P., Chowdhury J. R., Chowdhury N. R., Jansen P. L. Bilirubin UDP-glucuronosyltransferase 1 is the only relevant bilirubin glucuronidating isoform in man. J Biol Chem. 1994 Jul 8;269(27):17960–17964. [PubMed] [Google Scholar]
  5. CRIGLER J. F., Jr, NAJJAR V. A. Congenital familial nonhemolytic jaundice with kernicterus. Pediatrics. 1952 Aug;10(2):169–180. [PubMed] [Google Scholar]
  6. Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
  7. Chowdhury J. R., Novikoff P. M., Chowdhury N. R., Novikoff A. B. Distribution of UDPglucuronosyltransferase in rat tissue. Proc Natl Acad Sci U S A. 1985 May;82(9):2990–2994. doi: 10.1073/pnas.82.9.2990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Krawczak M., Reiss J., Cooper D. N. The mutational spectrum of single base-pair substitutions in mRNA splice junctions of human genes: causes and consequences. Hum Genet. 1992 Sep-Oct;90(1-2):41–54. doi: 10.1007/BF00210743. [DOI] [PubMed] [Google Scholar]
  9. Labrune P., Myara A., Hadchouel M., Ronchi F., Bernard O., Trivin F., Chowdhury N. R., Chowdhury J. R., Munnich A., Odièvre M. Genetic heterogeneity of Crigler-Najjar syndrome type I: a study of 14 cases. Hum Genet. 1994 Dec;94(6):693–697. doi: 10.1007/BF00206965. [DOI] [PubMed] [Google Scholar]
  10. Lerner M. R., Boyle J. A., Mount S. M., Wolin S. L., Steitz J. A. Are snRNPs involved in splicing? Nature. 1980 Jan 10;283(5743):220–224. doi: 10.1038/283220a0. [DOI] [PubMed] [Google Scholar]
  11. Mackenzie P. I., Owens I. S., Burchell B., Bock K. W., Bairoch A., Bélanger A., Fournel-Gigleux S., Green M., Hum D. W., Iyanagi T. The UDP glycosyltransferase gene superfamily: recommended nomenclature update based on evolutionary divergence. Pharmacogenetics. 1997 Aug;7(4):255–269. doi: 10.1097/00008571-199708000-00001. [DOI] [PubMed] [Google Scholar]
  12. Moghrabi N., Clarke D. J., Boxer M., Burchell B. Identification of an A-to-G missense mutation in exon 2 of the UGT1 gene complex that causes Crigler-Najjar syndrome type 2. Genomics. 1993 Oct;18(1):171–173. doi: 10.1006/geno.1993.1451. [DOI] [PubMed] [Google Scholar]
  13. Moghrabi N., Clarke D. J., Burchell B., Boxer M. Cosegregation of intragenic markers with a novel mutation that causes Crigler-Najjar syndrome type I: implication in carrier detection and prenatal diagnosis. Am J Hum Genet. 1993 Sep;53(3):722–729. [PMC free article] [PubMed] [Google Scholar]
  14. Orkin S. H., Antonarakis S. E., Loukopoulos D. Abnormal processing of beta Knossos RNA. Blood. 1984 Jul;64(1):311–313. [PubMed] [Google Scholar]
  15. Orkin S. H., Kazazian H. H., Jr, Antonarakis S. E., Ostrer H., Goff S. C., Sexton J. P. Abnormal RNA processing due to the exon mutation of beta E-globin gene. Nature. 1982 Dec 23;300(5894):768–769. doi: 10.1038/300768a0. [DOI] [PubMed] [Google Scholar]
  16. Ritter J. K., Chen F., Sheen Y. Y., Tran H. M., Kimura S., Yeatman M. T., Owens I. S. A novel complex locus UGT1 encodes human bilirubin, phenol, and other UDP-glucuronosyltransferase isozymes with identical carboxyl termini. J Biol Chem. 1992 Feb 15;267(5):3257–3261. [PubMed] [Google Scholar]
  17. Ritter J. K., Yeatman M. T., Ferreira P., Owens I. S. Identification of a genetic alteration in the code for bilirubin UDP-glucuronosyltransferase in the UGT1 gene complex of a Crigler-Najjar type I patient. J Clin Invest. 1992 Jul;90(1):150–155. doi: 10.1172/JCI115829. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Rogers J., Wall R. A mechanism for RNA splicing. Proc Natl Acad Sci U S A. 1980 Apr;77(4):1877–1879. doi: 10.1073/pnas.77.4.1877. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. SCHMID R., AXELROD J., HAMMAKER L., SWARM R. L. Congenital jaundice in rats, due to a defect in glucuronide formation. J Clin Invest. 1958 Aug;37(8):1123–1130. doi: 10.1172/JCI103702. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Seppen J., Bosma P. J., Goldhoorn B. G., Bakker C. T., Chowdhury J. R., Chowdhury N. R., Jansen P. L., Oude Elferink R. P. Discrimination between Crigler-Najjar type I and II by expression of mutant bilirubin uridine diphosphate-glucuronosyltransferase. J Clin Invest. 1994 Dec;94(6):2385–2391. doi: 10.1172/JCI117604. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Treisman R., Orkin S. H., Maniatis T. Specific transcription and RNA splicing defects in five cloned beta-thalassaemia genes. Nature. 1983 Apr 14;302(5909):591–596. doi: 10.1038/302591a0. [DOI] [PubMed] [Google Scholar]
  22. Yamada S., Tomatsu S., Sly W. S., Islam R., Wenger D. A., Fukuda S., Sukegawa K., Orii T. Four novel mutations in mucopolysaccharidosis type VII including a unique base substitution in exon 10 of the beta-glucuronidase gene that creates a novel 5'-splice site. Hum Mol Genet. 1995 Apr;4(4):651–655. doi: 10.1093/hmg/4.4.651. [DOI] [PubMed] [Google Scholar]

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