PTEN and Cowden disease: In humans, various autosomal dominant germline mutations in PTEN, ranging from missense point mutations to frameshift deletion mutations, are associated with PTEN hamartoma tumour syndrome (PHTS), a heterogeneous spectrum of disorders ranging from autism spectrum disorder (ASD) and brain patterning defects (Lhermitte–Duclos disease) to cancer predisposition syndromes (Cowden syndrome) (Hollander et al., 2011; Kurek et al., 2012a; Pilarski et al., 2011).