Diagnostic dilemma: A young woman with Fabry disease symptoms, no family history, and a "sequencing cryptic" α-galactosidase a large deletion

Ulla Feldt-Rasmussen, Robert Dobrovolny, Irina Nazarenko, Martin Ballegaard, Lis Hasholt, Åse K. Rasmussen, Erik I. Christensen, Soren S. Sorensen, Flemming Wibrand, Robert J. Desnick

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Fabry disease, an X-linked lysosomal storage disorder, results from the deficient activity of α-galactosidase A (α-Gal A). In affected males, the clinical diagnosis is confirmed by the markedly decreased α-Gal A activity. However, in female heterozygotes, the α-Gal A activity can range from low to normal due to random X-chromosomal inactivation, and diagnostic confirmation requires identification of the family's α-Gal A gene mutation. In a young female who had occasional acroparesthesias, corneal opacities, and 15 to 50% of the lower limit of normal leukocyte α-Gal A activity, α-Gal A sequencing in two expert laboratories did not identify a confirmatory mutation, presenting a diagnostic dilemma. A renal biopsy proved diagnostic and renewed efforts to detect an α-Gal A mutation. Subsequent gene dosage analyses identified a large α-Gal A deletion confirming her heterozygosity, and she was started on enzyme replacement therapy. Thus, gene dosage analyses can detect large deletions (> 50. bp) in suspect heterozygotes for X-linked and autosomal dominant diseases that are "sequencing cryptic," resolving molecular diagnostic dilemmas.

Original languageEnglish
Pages (from-to)314-318
Number of pages5
JournalMolecular Genetics and Metabolism
Volume104
Issue number3
DOIs
StatePublished - Nov 2011

Keywords

  • Fabry disease
  • Gene dosage analysis
  • Gene rearrangements
  • Lysosomal storage disease
  • α-galactosidase A

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