The need for vigilance: false-negative screening for adenylosuccinate lyase deficiency caused by deribosylation of urinary biomarkers

Clin Biochem. 2013 Dec;46(18):1899-901. doi: 10.1016/j.clinbiochem.2013.10.018. Epub 2013 Oct 30.

Abstract

Objectives: Adenylosuccinate lyase deficiency (dADSL) is a rare inherited metabolic disorder. Biochemical diagnosis of the disease is based on the determination of enormously elevated urinary levels of succinylaminoimidazole carboxamide riboside (SAICA-riboside) and succinyladenosine (SAdo). We report a case of false negative screening for dADSL caused by deribosylation of the urinary biomarkers SAICA-riboside and SAdo.

Design and methods: A thin-layer chromatography (TLC) method with Pauly reagent detection of SAICA-riboside was used as a screening method. High-performance liquid chromatography with diode-array detection (HPLC-DAD) and LC-MS/MS methods were used for the identification and quantitative determination of SAICA-riboside, SAdo, succinylaminoimidazole carboxamide (SAICA) and succinyladenine (SA).

Results: Following a negative TLC screening in a known case of dADSL, we analyzed urine using HPLC-DAD. The concentration of SAICA-riboside was 2.7mmol/mol creatinine (below the TLC detection limit), and we detected the two abnormal metabolites identified by LC-MS/MS as SAICA and SA. We showed that SAICA and SA were produced by deribosylation of SAICA-riboside and SAdo in the patient's urine. Studies performed by monitoring the production of SAICA and SA after the addition of SAICA-riboside and SAdo to the patient's urine and to urine samples from patients with urinary tract infections suggested that deribosylation is facilitated by bacterial enzymes.

Conclusions: Screening methods for the diagnosis of dADSL may be falsely negative due to bacteria-mediated deribosylation of SAICA-riboside and SAdo. HPLC-DAD or LC-MS/MS analyses allowing for simultaneous detection of SAICA-riboside, SAdo and their deribosylation products SAICA and SA should be preferentially used for the diagnosis of dADSL in urine.

Keywords: ADSL; Adenylosuccinate lyase deficiency; HPLC-DAD; LC–MS/MS; Purine metabolism; SA; SAICA; SAICA-riboside; SAdo; Succinyladenosine; Succinylaminoimidazole carboxamide riboside; Succinylpurines; TLC; adenylosuccinate lyase; adenylosuccinate lyase deficiency; dADSL; high-performance liquid chromatography with diode array detection; liquid chromatography–tandem mass spectrometry; succinyladenine; succinyladenosine; succinylaminoimidazole carboxamide; succinylaminoimidazole carboxamide riboside; thin-layer chromatography.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / analogs & derivatives
  • Adenosine / urine
  • Adenylosuccinate Lyase / deficiency*
  • Adenylosuccinate Lyase / urine
  • Aminoimidazole Carboxamide / analogs & derivatives*
  • Aminoimidazole Carboxamide / metabolism
  • Aminoimidazole Carboxamide / urine
  • Autistic Disorder
  • Bacterial Proteins / metabolism
  • Child, Preschool
  • Chromatography, High Pressure Liquid
  • Chromatography, Thin Layer / methods
  • Enterococcus faecalis
  • Enzymes / metabolism
  • False Negative Reactions
  • Humans
  • Klebsiella pneumoniae
  • Purine-Pyrimidine Metabolism, Inborn Errors / diagnosis*
  • Purine-Pyrimidine Metabolism, Inborn Errors / urine*
  • Ribonucleosides / metabolism
  • Ribonucleosides / urine*
  • Tandem Mass Spectrometry / methods
  • Urine / microbiology

Substances

  • Bacterial Proteins
  • Enzymes
  • Ribonucleosides
  • succinylaminoimidazole carboxamide riboside
  • Aminoimidazole Carboxamide
  • succinyladenosine
  • Adenylosuccinate Lyase
  • Adenosine

Supplementary concepts

  • Adenylosuccinate lyase deficiency