The Role of the Gut Microbiota in Patients With Kleefstra Syndrome

Kleefstra Syndrome (KS) is a rare monogenetic syndrome, caused by haploinsufficiency of the EHMT1 gene, an important regulator of neurodevelopment. The clinical features of KS include intellectual disability, autistic behavior and gastrointestinal problems. The gut microbiota may constitute a, yet unexplored, mechanism underlying clinical variation, as they are an important modifier of the gut-brain-axis. To test whether variation in the gut microbiota is part of KS, we investigated the gut microbiota composition of 23 individuals with KS (patients) and 40 of their family members. Both alpha and beta diversity of patients were different from their family members. Genus Coprococcus 3 was lower in abundance in patients compared to family members. Moreover, abundance of genus Merdibacter was lower in patients versus family members, but only in the participants reporting intestinal complaints. Within the patient group, behavioral problems explained 7% variance in the beta diversity. Also, within this group, we detected higher levels of Coprococcus 3 and Atopobiaceae _ uncultured associated with higher symptoms severity. Our results show significant differences in the gut microbiota composition of patients with KS compared to their family members, suggesting that these differences are part of the KS phenotype. ### Competing Interest Statement The authors have declared no competing interest.