Oral Microbiome Plays a Potential Role in Cleft Lip and Palate

Our fundamental question was whether the maternal oral microbiome in pregnancy contributes to the fate of non-syndromic cleft lip and palate (NS-CL/P) in the corresponding embryos. Thus, our study aimed to evaluate and compare the diversity and taxonomic composition of the oral microbiome of mothers who had children with NS-CL/P and mothers who had children without NS-CL/P at less than two months of age. Oral microbiota composition in unstimulated whole saliva samples from mothers of children with NS-CL/P (n=32; age ) and mothers with children without NS-CL/P (n=37; age) was determined by sequencing of the V3-V4 hypervariable regions of the 16S rRNA gene. The relative abundance of each ASV and richness estimators such as Shannon diversity index were calculated and compared between clinical groups. Principal coordinate analysis (PCA) was performed to assess the degree of variation between samples and clinical groups (beta diversity). At the genus level, the most abundant microorganisms were Prevotella, Streptococcus, Haemophilus, Veillonella, and Neisseria, in both groups. There were significant differences in microbial richness between CL/P and control groups (p<0.05), indicating that the number of different bacterial taxonomic groups was lower in CL/P than in control. Furthermore, there was a significant difference in beta diversity between CL/P and control groups (p-value < 0.005). Of interest, 152 ASVs were more enriched in CL/P and 298 were more enriched in controls, being Prevotella the genus with the largest number of ASVs differentially abundant. Our results show new insights to help understand new candidate NS-CL/P environmental predisposition factors and to better ascertain the actual contribution of these specific maternal microbiota profiles.