A tandem mass spectrometry diagnostic test for newborn screening of Tay-Sachs and Sandhoff diseases

Summary The goal of this project is to develop a tandem mass spectrometry assay for newborn screening of GM2-gangliosidosis for which several treatment options are being developed. GM2- gangliosidosis includes Tay-Sachs and Sandhoff diseases, inherited metabolic disorders which cause a progressive deterioration of nerve cells. Tay-Sachs disease is caused by HexA enzyme deficiency and Sandhoff disease is caused by deficiency of both HexA and HexB enzymes. The incidence of these disorders is high among certain populations around the world. For example, in the Ashkenazi Jewish population the Tay-Sachs incidence is about 1 in every 3,500 newborns and the carrier frequency is 1 in every 29 individuals. The carrier frequency of Sandhoff disease range from 1:310 in the general population to 1:7 in isolated communities with a high degree of consanguinity. In this project, a method for simultaneous detection of Tay-Sachs and Sandhoff disease suitable for newborn screening will be developed. A punch from a dried blood spot (DBS) on a newborn screening card is used as a source of the enzyme (HexA and HexB). DBS will be incubated with a cocktail containing two synthetic substrates (a specific HexA substrate and a HexA/B substrate) to allow formation of two enzymatic products which will be then quantified by tandem mass spectrometry (MS/MS). Our method would require one single incubation and one MS/MS injection.Newborn screening for treatable lysosomal storage diseases is warranted since initiation of treatment soon after birth leads to a better treatment outcome. Our research team has developed technology for newborn screening of a series of lysosomal storage diseases which is commercialized by our business branch (GelbChem, LLC). This proposal aims to develop a mass spectrometry method for newborn screening of Tay-Sachs and Sandhoff, two closely related lysosomal storage diseases, for which treatments are being developed.