Gene structure, chromosomal location, and expression pattern of maleylacetoacetate isomerase

José Manuel Fernández-Cañón, Jim Hejna, Carol Reifsteck, Susan Olson, Markus Grompe

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


The gene for maleylacetoacetate isomerase (MAAI) (EC was the last gene in the mammalian phenylalanine/tyrosine catabolic pathway to be cloned. We have isolated the human and murine genes and determined their genomic structure. The human gene spans a genomic region of ~10 kb, has 9 exons ranging from 50 to 528 bp in size, and was mapped to 14q24.3-14q31.1 using fluorescence in situ hybridization. The complete catabolic pathway of phenylalanine/tyrosine is normally restricted to liver and kidney, but the maleylacetoacetate isomerase gene is expressed ubiquitously. This suggests a possible second role for the MAAI protein different from phenylalanine/tyrosine catabolism. We have searched for mutations in the maleylacetoacetate isomerase gene in four cases of unexplained severe liver failure in infancy with clinical similarities to hereditary tyrosinemia type I (pseudotyrosinemia). Several amino acid changes were identified, but all were found to retain MAAI activity and thus represent protein polymorphisms. We conclude that MAA deficiency is not a common cause of the pseudotyrosinemic phenotype.

Original languageEnglish (US)
Pages (from-to)263-269
Number of pages7
Issue number3
StatePublished - Jun 15 1999


  • Gene structure
  • Liver failure
  • Maleylacetoacetate isomerase
  • Pseudotyrosinemia

ASJC Scopus subject areas

  • Genetics


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