Development of a universal STR panel for PGT-M for cystic fibrosis, taking into account the specific haplotype of chromosomes carrying the CFTR F508del variant

Background. Preimplantation genetic testing (PGT) is developing as a variant of early prenatal prevention of hereditary diseases. Targeted variant PGT for monogenic disease (PGT-M) involves a combination of pathogenic variant and indirect DNA markers analysis. The list of DNA markers linked to the CFTR gene for the purposes of cystic fibrosis PGT (PGT CF) varies by different authors.

Aim: development of a panel of STR-markers for PGT CF.

Methods Intragenic and extragenic STR markers linked to the CFTR gene were selected using scientific literature data and databases. The panel of markers was tested on DNA samples from seven families with CF, in which the disease is caused by the pathogenic F508del variant. Only one family had CFTRdele2,3(21kb) as the second mutation. For testing, PCR and fragment analysis methods were used.

Results. 15 main and 4 additional STR markers have been selected for a panel. Most of the samples of the parents carrying the pathogenic variant of the CFTR gene confirmed the sufficient information content of the main STR panel. An additional panel was required due to the fact that one of the studied samples revealed low information rate for linked markers because of a special haplotype of the chromosome carrying the normal allele.

Conclusions. The developed panel, taking into account the specific F508del haplotype, can serve as a basis for PGT CF.

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