A Kivrane wrote a manuscript draft and together with V Igumnova, designed and performed experimental work and NGS sequencing data analysis. J Kimsis, L Freimane and D Sadovska contributed to the experiment design and the interpretation of NGS sequencing data. A Viksna was responsible for the clinical care of the patients and, together with I Pole, contributed to the collection of the test samples. R Ranka supervised the research work, critically revised and approved the final version of the manuscript. All authors approved the final manuscript.