Children with Down syndrome have dysbiosis in the salivary microbiome: study

Down syndrome (DS), a most frequently occurring genetic disorder, is associated with oral morphological abnormalities and higher incidence rates of oral diseases. Recent studies have analyzed the oral microbiome to elucidate their relationships with oral diseases and general health; however, reports on the oral microbiome in individuals with DS are scarce. This study aimed to characterize the oral microbiome in children with Down syndrome.

A total of 54 children aged 1–13 years were enrolled in this case-control study. Of these children, 27 had DS (Case: DS group) and 27 were age-matched healthy children (Control: ND group). Saliva in the oral cavity was collected with a swab, cultured, and tested for cariogenic and periodontopathic bacteria by quantitative polymerase chain reaction (qPCR) detection, and the salivary microbiome was analyzed using next-generation sequencing. The student's t-test, Fisher's exact test, Mann–Whitney U test, and permutational multivariate analysis of variance were used for statistical analysis.

The Results:

• Results of culture and qPCR detection tests for cariogenic and periodontopathic bacteria showed no significant differences in the detected bacteria between the Down syndrome and ND groups, with the exception of a significantly higher detection rate of Candida albicans in children with Down syndrome with mixed dentition.
• A comparison of the salivary microbiomes by 16S sequencing showed no significant difference in α diversity; however, it showed a significant difference in β diversity.
• Children with Down syndrome had a higher relative abundance of Corynebacterium and Cardiobacterium, and lower relative abundance of TM7.

Thus, this study provided basic data on the salivary microbiome of children with Down syndrome and showed the microbiological markers peculiar to children with Down syndrome. However, further research to identify the relationship with oral diseases is warranted.

Reference:

Morishima, S., Takeda, K., Greenan, S. et al. Salivary microbiome in children with Down syndrome: a case-control study. BMC Oral Health 22, 438 (2022). https://doi.org/10.1186/s12903-022-02480-z

Keywords:

Morishima, S., Takeda, K., Greenan, S, Salivary, microbiome, children, Down syndrome, case-control study, BMC Oral Health, Saliva, Microbiota, Children