METHOD FOR ANALYSING MITOCHONDRIAL DNA FOR NON-INVASIVE PRENATAL TESTING Russian patent published in 2022 - IPC G01N33/50 C12Q1/68 C40B20/00 

FIELD: biotechnology.

SUBSTANCE: described is a method for analysing mitochondrial DNA for non-invasive prenatal testing, wherein bam files with aligned readings of the human genome are obtained by mass parallel sequencing of extracellular DNA of blood plasma of the mother using semiconductor technology. Additional analysis modules are therein used, using mitochondrial DNA readings, wherein mitochondrial readings are extracted from the total volume of sequenced data, the mtDNA rate in the sample is calculated by the formula

.

In order to further identify the level of contamination of the sample by the maternal material and attribute the sample to the high risk group based on an obtained false negative result of NIPT in the case of obtaining a value of the mtDNA rate exceeding 0.0005 (5×10^-4), the percentage of mtDNA coverage is calculated by the formula

.

Bam files with mtDNA coverage below 50% are filtered as unsuitable for mitochondrial analysis, mtDNA variants, namely indels and single-nucleotide substitutions, are found and annotated in order to identify pathogenic and conditionally pathogenic ClinVar variants, analysing mtDNA haplogroups, completely to the level of individual clades in case of a sufficient level of coverage of at least 80% of mitochondrial DNA, or approximately to the superclade level for samples with mtDNA coverage below 80%.

EFFECT: expanded functionality of NIPT and improved quality of diagnostics due to the introduction of the stages of controlling the contamination and quality of sample transportation; invention allows for a more complete analysis of the data of mass parallel sequencing of extracellular DNA of blood plasma, including analysing mtDNA haplogroups and finding nucleotide variants.

1 cl, 2 dwg