Identification and functional analysis of cystathionine beta-synthase gene mutations in patients with homocystinuria

Sook Jin Lee, Dong Hwan Lee, Han Wook Yoo, Soo Kyung Koo, Eun Sook Park, Joo Won Park, Hun Gil Lim, Sung Chul Jung

Research output: Contribution to journalArticlepeer-review

25 Scopus citations

Abstract

Homocystinuria is an autosomal recessive inborn error of metabolism that is most often caused by mutation in the cystathionine beta-synthase (CBS) gene. Patients may develop serious clinical manifestations such as lens dislocation, mental retardation, osteoporosis, and atherothrombotic vascular disease. Over 100 mutations have been reported, but so far, none have been reported in Korea. Mutation analysis of the CBS gene in six Korean patients with homocystinuria was performed by direct sequencing. Eight mutations were identified, including four known mutations (T257M, R336C, T353M, and G347S) and four novel mutations (L154Q, A155V, del234D, and A288T). All patients were compound heterozygotes. To characterize these mutations, normal or mutated forms of CBS were cloned into pcDNA3.1 expression vector followed by transfection into mammalian cells for transient expression. Whereas the expression levels of mutant proteins were comparable to that of normal control, enzyme activities of all the mutant forms were significantly decreased. In addition, a novel single nucleotide polymorphism, R18C, was identified, which showed one-third to two-thirds the enzyme activity of wild type and 1% of the allele frequency in normal control. The spectrum of mutations observed in Korean patients bears less resemblance to those observed in Western countries.

Original languageEnglish
Pages (from-to)648-654
Number of pages7
JournalJournal of Human Genetics
Volume50
Issue number12
DOIs
StatePublished - Dec 2005

Keywords

  • CBS
  • Cystathionine beta-synthase
  • Expression
  • Functional analysis
  • Homocystinuria
  • Korean
  • Mutation

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