Gastrointestinal dysfunction in patients with Mowat–Wilson syndrome is associated with feeding difficulties and altered plasma neurotransmitters

Background Intestinal dysfunction is prevalent in children with Mowat–Wilson syndrome (MWS), yet its underlying mechanisms remain unclear. This study aimed to characterize intestinal symptoms, feeding patterns, and fasting plasma neurotransmitter profiles in patients with MWS, and to explore their potential relationships. Methods Three complementary assessments were conducted, including a questionnaire assessing defecation difficulties and stool characteristics; a structured questionnaire assessing feeding difficulties, caregiver-reported dietary composition (including the proportion of meat), and complementary feeding practices; and targeted fasting plasma neurotransmitter profiling using UPLC–TQ–MS. Results Among 35 patients with MWS, 86% had intestinal symptoms, including constipation (69%) and Hirschsprung disease (17%). In the feeding/diet analysis, 44.4% (4/9) of patients with MWS reported feeding difficulties. Compared with age-matched healthy controls ( n = 10), patients with MWS ( n = 9) had a significantly lower proportion of meat and delayed introduction of meat-based complementary foods (10.5 months vs. 7.9 months). In the plasma analysis, patients with MWS ( n = 6) exhibited significantly reduced plasma levels of serotonin and taurine, alongside elevated levels of GABA and dopamine, compared with age-matched healthy controls ( n = 10). Conclusion These findings confirm the high prevalence of constipation-predominant intestinal dysfunction in patients with MWS. Collectively, our findings support further investigation of associations among feeding difficulties, a lower proportion of meat in dietary composition, and an altered fasting plasma neurotransmitter profile (including lower serotonin in a small subset), which may be relevant to gut dysmotility in patients with MWS. This diet–neurotransmitter axis offers a working model for understanding intestinal dysfunction in patients with MWS, yet direct quantification of dietary and circulating tryptophan in future studies is needed to validate this pathway.