Trichohepatoenteric syndrome (THES) is a very rare autosomal recessive genetic disorder, which is characterized by intractable diarrhea during infancy, dysmorphic features, immunodeficiency, and a failure to thrive. There are still significant difficulties for patients and clinicians in terms of the management of THES, even though its molecular basis has been uncovered in the last decade. In this article, we have presented two cases relating to siblings that have been diagnosed with the condition.Concerning one of the patients, we described a novel variation (c.2114 + 5G > A) in the TTC37 gene and a mild clinical course; meanwhile, the other one was clinically diagnosed with THES at 17 years of age, but they had seizures and died suddenly. These cases expand the spectrum of clinical findings in relation to THES. K E Y W O R D S intractable diarrhea, trichohepatoenteric syndrome, TTC37 gene 1 | INTRODUCTION Trichohepatoenteric syndrome (THES) (OMIM #222470) is a rare genetic disorder that is characterized by intractable diarrhea that generally occurs in the neonatal period. Other clinical signs include woolly hair, intrauterine growth restriction, facial dysmorphism, immune deficiency, liver disease, skin abnormalities, cardiac abnormalities, and short stature (Fabre et al., 2017). Stankler et al. (1982) described THES for the first time in two siblings who had intractable diarrhea, intrauterine growth restriction, and facial dysmorphism; later, it was reported by Girault et al. (1994) that immune system