An Alu-mediated rearrangement causing a 3.2kb deletion and a novel two base pair deletion in AAAS gene as the cause of triple A syndrome

Mol Genet Metab. 2007 Dec;92(4):359-63. doi: 10.1016/j.ymgme.2007.08.116. Epub 2007 Oct 2.

Abstract

Triple A syndrome is an autosomal recessive disorder resulting from deleterious mutations in the AAAS gene located on chromosome 12q13. Typical clinical presentation of this syndrome includes adrenal insufficiency, achalasia, and alacrima. A 10-year-old female was diagnosed with Triple A syndrome at the age of 1 year. Initial analysis of the AAAS gene revealed apparently homozygosity for a novel 2bp deletion in exon 1. The father of the patient was heterozygous for this mutation but the mother and the maternal grandparents were apparently homozygous for the wild-type. Further studies demonstrated that the patient carried an intragenic 3.2kb deletion within both 5' and 3' breakpoints located within Alu-repeats. The deletion includes 5'-flanking region, exon 1, intron 1, exon 2, and part of intron 2 sequences of the AAAS gene. This Alu-mediated deletion was inherited from her mother and maternal grandmother. This is the first report that Alu-mediated rearrangement in conjunction with a novel two-bp deletion of the AAAS gene is a cause of Triple A syndrome. The results of our study lead to the hypothesis that an Alu-mediated mechanism may be responsible for large alterations in the AAAS gene. We also stress the importance of studying the family in genetic recessive diseases, such as Triple A syndrome, to avoid incorrect diagnosis and to provide accurate genetic counseling.

MeSH terms

  • Alu Elements / genetics*
  • Child, Preschool
  • Chromosome Disorders / genetics*
  • Chromosomes, Human, Pair 12 / genetics
  • Female
  • Gene Rearrangement / genetics*
  • Genotype
  • Humans
  • Male
  • Mutation / genetics
  • Nerve Tissue Proteins / genetics*
  • Nuclear Pore Complex Proteins / genetics*
  • Pedigree
  • Syndrome

Substances

  • AAAS protein, human
  • Nerve Tissue Proteins
  • Nuclear Pore Complex Proteins