Angelman syndrome is a rare genetic condition characterised by severe learning difficulties and neurological problems. The majority of cases result from a deletion of part of chromosome 15 which usually affects a gene called E6AP, thought to be the primary molecule responsible Angelman syndrome. HERC2 is another gene that is commonly deleted in Angelman syndrome patients. However, although HERC2 was recently shown to be a biological partner of E6AP, it has never been associated with the features of Angelman syndrome. We studied an unusual developmental delay syndrome found amongst the Old Order Amish which although distinct, displays a number of clinical similarities with Angelman syndrome. Our molecular studies showed that a mutation in the HERC2 gene is responsible for this condition. Taken together our studies suggest a previously unrecognised role of the HERC2 gene in Angelman syndrome. (By Dr Andrew H Crosby, http://jmg.bmj.com/content/early/2012/12/13/jmedgenet-2012-101367 )