*Background:* 

Mendelian disorders are individually rare but collectively common, forming a "long tail" of genetic disease. More than 20 million people worldwide suffer from a disease in this long tail before the age of 25, with minorities and developing countries at highest risk and with the number of carriers far in excess of this figure. Importantly, the Jewish community’s campaign for universal Tay-Sachs screening shows that these incurable diseases can nevertheless be prevented if carrier status is known before conception. A single highly-accurate assay for the long tail of Mendelian disease would allow us to scale this successful campaign up to the general population, thereby improving... |