Identification of an Alu-mediated tandem duplication of exons 8 and 9 in a patient with mitochondrial acetoacetyl-CoA thiolase (T2) deficiency

A tandem repeat of exons 8 and 9 was identified in the cDNA for mitochondrial acetoacetyl-CoA thiolase (T2) in a typical T2 deficient patient. Routine mutation analysis using PCR at the genomic level had failed to identify any mutations. Alu element-mediated unequal homologous recombination between an Alu-Jo in intron 7 and another Alu-Jo in intron 9 appears to be responsible for this duplication.