Identification of developmental disorders including autism spectrum disorder using salivary miRNAs in children from Bosnia and Herzegovina

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by major social, communication and behavioural challenges. The cause of ASD is still unclear and it is assumed that environmental, genetic and epigenetic factors influence the risk of ASD occurrence. MicroRNAs (miRNAs) are short 21-25 nucleotide long RNA molecules which post-transcriptionally regulate gene expression. MiRNAs play an important role in central nervous system development; therefore, dysregulation of miRNAs is connected to changes in behaviour and cognition observed in many disorders including ASD. Based on previously published work, on diagnosing ASD using miRNAs, we hypothesized that miRNAs can be used as biomarkers in children with suspected developmental disorders (DD) including ASD within Bosnian-Herzegovinian (B&H) population. 14 selected miRNAs were tested on saliva of children with suspected developmental disorders including ASD. The method of choice was qRT-PCR as a relatively cheap method available in most diagnostic laboratories in low to mid-income countries (LMIC). Out of 14 analysed miRNAs, 6 were differentially expressed between typically developing children and children with some type of developmental disorder including autism spectrum disorder. Using the most optimal logistic regression, we were able to distinguish between ASD and typically developing (TD) children. We have found 5 miRNAs as potential biomarkers. From those, 3 were differentially expressed within the ASD cohort. All 5 miRNAs had shown good chi-square statistics within the logistic regression performed on all 14 analysed miRNAs. The accuracy of 5-miRNAs model training set was 90.2%, while the validation set had a 90% accuracy. This study has shown that miRNAs may be considered as biomarkers for ASD detection and may be used to identify children with ASD along with standard developmental screening tests. By combining these methods we may be able to reach a reliable and accessible diagnostic model for children with ASD in LMIC such as B&H.

Recent Progress on Relevant microRNAs in Autism Spectrum Disorders

“…Hicks et al concluded that the differentially expressed salivary miRNAs in children with ASD can affect their behavior and also identify ASD patients and normal individuals [ 136 ]. Through the miRNA expression profiling of 14 autistic salivary samples by qRT-PCR, Sehovic et al found that six salivary miRNAs were differentially expressed in ASD children and TD children, and also identified five miRNAs, including miR-7-5p, miR-23a-3p, miR-32-5p, miR-140-3p, and miR-628-5p, as potential biomarkers of ASD children [ 137 ]. As shown in Figure 2 b, there are no common dysregulated miRNAs in the two studies of saliva biomarkers [ 136 , 137 ], which may be caused by the different age distributions of the saliva samples.…”

“…Through the miRNA expression profiling of 14 autistic salivary samples by qRT-PCR, Sehovic et al found that six salivary miRNAs were differentially expressed in ASD children and TD children, and also identified five miRNAs, including miR-7-5p, miR-23a-3p, miR-32-5p, miR-140-3p, and miR-628-5p, as potential biomarkers of ASD children [ 137 ]. As shown in Figure 2 b, there are no common dysregulated miRNAs in the two studies of saliva biomarkers [ 136 , 137 ], which may be caused by the different age distributions of the saliva samples. Hicks et al used samples from 2–6 year olds [ 136 ], while Sehovic et al used samples from children with an average age of 5.8 years [ 137 ].…”

“…As shown in Figure 2 b, there are no common dysregulated miRNAs in the two studies of saliva biomarkers [ 136 , 137 ], which may be caused by the different age distributions of the saliva samples. Hicks et al used samples from 2–6 year olds [ 136 ], while Sehovic et al used samples from children with an average age of 5.8 years [ 137 ]. These findings suggest that these dysregulated salivary miRNAs may potentially be used as biomarkers of ASD to distinguish ASD and normal individuals.…”

Potential of Salivary Biomarkers in Autism Research: A Systematic Review

“…They found that a subset of salivary miRNAs is also associated with measures of adaptive and ASD behaviors. In addition to the RNA sequencing approach, a qRT-PCR based analysis of salivary miRNA was published by Sehovic et al in 2020 [ 74 ]. Using this relatively cheap method available in most diagnostic laboratories, fourteen miRNAs were analyzed in typically developing children and children with some type of developmental disorder including ASD.…”

“…For example, miR-146b-5p, piR-6463, piR-24085, and miR-148a-5p, associated with behavior parameters and/or change over time in a longitudinal study [ 75 ], were also included in a diagnostic panel [ 71 ] or identified by RNA sequencing [ 73 ]. In addition, miR-23a-3p was similarly identified as overexpressed by RNA sequencing and by qPCR [ 66 , 74 ]. These findings provide pieces of preliminary evidence that RNAs represent promising markers for monitoring developmental trajectory, therapeutic efficiency, and prognosis of ASD.…”