Methods for identifying and using small RNA predictors

A method for identifying small RNA (sRNA) predictors for neurodegenerative disease, comprising:

• (1) providing sRNA sequencing data from an experimental cohort and a comparator cohort of solid tissue or biological fluid samples, the sRNA sequencing data being generated by a sequencing-by-synthesis sequencing platform;
• wherein the samples of the experimental cohort and the samples of the comparator cohort are from patients having the presence or absence, respectively, of a neurodegenerative disease;
• wherein the sRNA sequencing data comprises sequence reads having adaptor sequences at 5′- and 3′-ends, and sRNA sequences are defined from the sequence reads by deletion of the adaptor sequences so as to identify variations at the 3′- and 5′-ends of the sRNA sequences, the sRNA sequences being defined without consolidating sequence reads to a reference sequence;
• (2) selecting sRNA sequences that are present in at least 10% of the samples in the experimental cohort and which are not present in any samples of the comparator cohort, thereby identifying positive sRNA predictors, and wherein
• at least one selected sRNA sequence is an isomiR;
• and
• (3) detecting the presence and absence of the selected positive sRNA predictors in RNA extracted from samples of a validation cohort using a quantitative or qualitative PCR assay that is specific for the sRNA predictors, wherein the PCR assay employs a stem loop primer and a fluorescently-labeled probe;
• thereby identifying sRNA predictors for the neurodegenerative disease.