Sensitivity, specificity and predictive value of the genetic analysis of SLC3A1 gene variants used for the diagnosis of cystinuria among the Spanish population

Objective. To test the clinical usefulness of the analysis of point mutatio ns R452W, M467T, 114C > A, 231T > A, 1136 + 3delT and 1332 + 7T > C in the gene SLC3A1 as well as their possible haplotypes used for the diagnosis of cystinuria in the mediterranean spanish population. Material and methods. A total of 48 patients with cystinuria, 44 relatives without cystinuria, and 81 healthy controls were studied. A genetic analysi s was conducted in order to identify variants in the gene SLC3A1. The sensi tivity, specificity, and predictive value for each genetic variant and for the possible haplotypes were calculated. Results. The specificity of mutations M467T, R452W, and 231T > A used for t he diagnosis of cystinuria in the general population or for the different s ubtypes of cystinuria in involved families, was higher than 90%; nevertehel ess, none of the analysed variants reached a sensitivity higher than 80%. I n the study of haplotypes, the highest sensitivity was obtained with the ha plotype CTTT (83.8%); however, its specificity and predictive value were lo w (20.6% and 53.4%, respectively). Conclusions. The studied genetic variants did not show enough clinical usef ulness.