PTEN and juvenile polyposis syndrome: In addition to large deletions of BMPR1a being identified in patients with JPS, cases of JPI have been observed in patients with contiguous deletion of PTEN and BMPR1a, which often presents in the first two years of life with severe GI bleeding, diarrhoea, exudative enteropathy and rectal prolapse [4, 5, 18, 36–38].