PCDH9 and autism spectrum disorder: Genetic abnormalities in SLC16A1 have been identified to cause congenital hyperinsulinism (Otonkoski et al., 2007); PCDH9 is a non-clustered protocadherin, mutations in humans are associated with autism spectrum disorders and its expression in glioblastoma suggest a role as tumor suppressor (Kim et al., 2011).