First-trimester diagnosis of infantile neuronal ceroid lipofuscinosis (INCL) using PPT enzyme assay and CLN1 mutation analysis.

Infantile neuronal ceroid lipofuscinosis (INCL) is a progressive neurodegenerative disorder in childhood which is caused by the deficiency of the lysosomal palmitoyl-protein thioesterase (PPT) encoded by the CLN1 gene. In a pregnancy at risk for INCL, chorionic villi (CV) were studied using a novel fluorometric PPT enzyme assay in combination with mutation-analysis of the CLN1 gene. The PPT activity in chorionic villi was found to be deficient and homozygosity for the C451T mutation in CLN1 was found. The pregnancy was terminated and the PPT deficiency was confirmed in cultured CV cells as well as in the cultured fetal skin fibroblasts. This report shows the first early prenatal diagnosis of INCL performed by fluorometric enzyme analysis and mutation analysis of the CLN1 gene.