Citrullinemia type I, classical variant. Identification of ASS-p~G390R (c.1168G>A) mutation in families of a limited geographic area of Argentina: a possible population cluster.

OBJECTIVE: Citrullinemia type I (CTLN1) is an urea cycle defect caused by mutations in the argininosuccinate synthetase gene. We report the first identification in Argentina of patients with CTLN1 in a limited geographic area. DESIGN AND METHODS: Molecular analysis in patient/relatives included PCR, sequencing and restriction enzyme assay. RESULTS: The studied families showed the same mutation: ASS~p.G390R, associated with the early-onset/severe phenotype. CONCLUSION: We postulate a possible population cluster. A program to know the carrier frequency in that population is in progress.