Screening tests for adenylosuccinase deficiency

Abstract

Introduction: Adenylosuccinase (ADS) deficiency is a rare disorder of purine metabolism which presents as psychomotor retardation of varying degree. Systematic screening of children with unexplained mental retardation is necessary to establish the prevalence of ADS. Methods: Three screening methods utilizing thin-layer chromatography for the detection of the succinylpurines which are excreted in this deficiency have been evaluated with respect to sensitivity, speed and cost. Results: Two of these methods were found to be reliable and rapid and were used to screen for ADS deficiency in a pediatric population of 2642 subjects, either referred for investigation of neurological abnormalities, or in institutions for children with neurological handicap. Two known positive cases investigated blind were easily detected by both screening methods selected; both urines were from cases reported previously from Belgium. In addition three new cases were found in the Czech population. Discussion: Either of the two methods we used would be suitable for screening a large population for ADS deficiency. Such screening would provide much needed information about the prevalence and the clinical phenotype of this disorder.