Identification of new mutations in the adenylosuccinate lyase gene associated with impaired enzyme activity in lymphocytes and red blood cells

We determined the DNA sequence of the adenylosuccinate lyase (ASL) gene from a 13 year-old female, who showed a reduced ASL enzymatic activity in lymphocytes and red blood cells and suffered from severe psychomotor retardation. The patient was the offspring of a non-consanguineous marriage. She was found to be compound heterozygous for two missense-mutations located on different alleles (C-300-G and G(1266)-T): the first mutation replaces Pro75 by Ala, the second mutation replaces Asp397 by Tyr. (C) 1998 Elsevier Science B.V.