A Major Step on the Road to Understanding a Unique Posttranslational Modification and Its Role in a Genetic Disease

The posttranslational conversion of cysteine to Cα-formylglycine in the catalytic site of mammalian sulfatases is deficient in the rare but devastating disorder multiple sulfatase deficiency (MSD). Two papers in this issue of Cell report the cloning of a gene responsible for this activity.