Evaluation of the novel variants found incidentally during diagnostic process in terms of N6-methyladenosine (m6A) modification

Abstract

Introduction N6-methyladenosine (m6A) is the most abundant RNA modification which is found in mRNAsand known to effect splicing, stability and translational efficiency of mRNAs. Methylation and demethylationof adenine is catalyzed by specific type of enzymes. When methylated, adenine (m6A) can be recognized by aspecific group of proteins with YT521-B homology (YTH) domain. Binding of YTH-domain protein leads todownstream events which result in differential expression of the gene. N6-methylation targets the adenineresidues which are located in a consensus sequence characterized by DRACH motif, and some SNPs (m6ASNP)may cause loss or gain of this motif. In our department, we use Sanger sequencing for the diagnosis ofmore than 400 single-gene diseases. In addition to disease causing mutation, we identify numerous novelvariants, which may play modifier role in disease phenotype. To investigate whether these novel variants maycause loss or gain of DRACH motif, we have retrospectively evaluated variants found in our patients. Materialand methods For known m6A-SNPs, we used databases. Scoring loss or gain of DRACH motif in the presenceof each variant found in our patients was performed with Python3.6. Results From databases, we exported morethan 280.000 m6A-SNPs. In approximately 2.000 of our patients analyzed to date, we have found 1290 knownSNPs. None of these SNPs was included in m6A-SNP dataset. Investigation of novel variations which is still inprogress will be presented. Discussion This ongoing study is expected to help explaining the clinicalheterogeneity of some set of our patients.