Autoimmune enteropathy (AIE) is a rare clinical condition characterized by intractable diarrhea of early childhood.¹ While AIE can feature both simple Mendelian inheritance or a complex multifactorial pattern, the pathogenesis remains unclear in many cases.² This is important for providing an accurate recurrence risk as affected individuals survive until adulthood and have children. Here, we describe a father and son with AIE who had clinically distinct courses. Exome sequencing has revealed a novel missense variant, c.2147C>T; (p.Thr716Met) in the signal transducer and activator of transcription 3 gene (STAT3) in both the father and son, consistent with autosomal dominant inheritance. STAT3 regulates immune reactions, and mutations in this gene have previously been associated with autoimmunity and Hyper IgE syndrome, but not AIE. Further studies are needed to assess the functional effect of this variant as it relates to the phenotype.