PT - JOURNAL ARTICLE AU - Y V Voznyi AU - J L M Keulemans AU - G M S Mancini AU - C E Catsman-Berrevoets AU - E Young AU - B Winchester AU - W J Kleijer AU - O P van Diggelen TI - A new simple enzyme assay for pre- and postnatal diagnosis of infantile neuronal ceroid lipofuscinosis (INCL) and its variants AID - 10.1136/jmg.36.6.471 DP - 1999 Jun 01 TA - Journal of Medical Genetics PG - 471--474 VI - 36 IP - 6 4099 - http://jmg.bmj.com/content/36/6/471.short 4100 - http://jmg.bmj.com/content/36/6/471.full SO - J Med Genet1999 Jun 01; 36 AB - Palmitoyl-protein thioesterase (PPT) deficiency was recently shown to be the primary defect in infantile neuronal ceroid lipofuscinosis (INCL). The available enzyme assay is complicated and impractical for diagnostic use and is, in practice, unavailable. We have developed a new fluorimetric assay for PPT based on the sensitive fluorochrome 4-methylumbelliferone. This PPT assay is simple, sensitive, and robust and will facilitate the definition of the full clinical spectrum associated with a deficiency of PPT. PPT activity was readily detectable in fibroblasts, leucocytes, lymphoblasts, amniotic fluid cells, and chorionic villi, but was profoundly deficient in these tissues from INCL patients. Similarly, a deficiency of PPT was shown in patients with the variant juvenile NCL with GROD. These results show that rapid pre- and postnatal diagnosis can be performed with this new enzyme assay for PPT.