Inflammatory bowel diseases (IBDs) are complex and severe disorders ascribed to alterations in the dialogue between the microbiota and the host immune system (Bouma & Strober, 2003; Maloy & Powrie, 2011). By using whole‐exome sequencing (WES), we report the identification of compound heterozygous ALPI mutations in two unrelated patients displaying severe intestinal inflammation and autoimmunity. ALPI encodes the Intestinal alkaline phosphatase, a brush border metalloenzyme that catalyses phosphate hydrolysis of the lipid moiety of LPS and thereby drastically reduces LPS pro‐inflammatory activity (Schromm et al, 1998; Goldberg et al, 2008).

Inflammatory bowel diseases (IBDs) are complex and severe disorders ascribed to alterations in the dialogue between the microbiota and the host immune system (Bouma & Strober, 2003; Maloy & Powrie, 2011). By using whole‐exome sequencing (WES), we report the identification of compound heterozygous ALPI mutations in two unrelated patients displaying severe intestinal inflammation and autoimmunity. ALPI encodes the Intestinal alkaline phosphatase, a brush border metalloenzyme that catalyses phosphate hydrolysis of the lipid moiety of LPS and thereby drastically reduces LPS pro‐inflammatory activity (Schromm et al, 1998; Goldberg et al, 2008).

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