Interestingly, the deletion detected in this patient has almost identical breakpoints to those described in the individual with West Syndrome PLCB1-EIEE.9 It is likely that the LINEs (which represent highly homologous repetitive sequences) at the breakpoint sites predispose to chromosomal rearrangements, thereby playing an important mechanistic role in the way in which recurrent deletions occur. Here, PLCB1 is linked to infantile spasms.