Exome sequencing is a method of investigating all of a person¹s genes at the same time to look for the mutation that is causing their illness. It is often used when targeted genetic testing has run into a dead end. However, half to three quarters of patients who have their exome sequenced will still not receive a Œgenetic diagnosis¹. This research by Drs. Anna Need, Vandana Shashi and colleagues explores the reasons that some families do not get a diagnosis through exome sequencing the first time, and presents three patients who received a diagnosis when their exome data was re-analysed.  (By Dr. Anna Need, http://jmg.bmj.com/content/early/2016/11/29/jmedgenet-2016-104306 )