PGT preparation, relatives

Test covered by the reimbursement:
Clinical expertise code:
Test without reimbursement:
Peripheral blood, Buccal swab
Turnover time:
4 weeks
2 weeks


Peripheral blood | 1x 3 ml of whole blood in K3 EDTA tube
Storage after examination: week after the report is issued 2 – 8°C
Buccal swab | 2x swab stick for buccal swab collection
Storage after examination: week after the report is issued 2 – 8°C
Isolated DNA from blood | 10–100 ng/μL of isolated DNA from blood in a PCR tube of at least 15 μL.
Storage after examination: stored in a DNA archive without restriction 15°C

Quick test description:

DNA testing of the patient’s relatives by karyomapping (SNP array) to determine the parental origin of chromosome segments in the examined embryos and to possibly detect various types of genetic disorders, including monogenic ones.

Test details:

To perform PGT by karyomapping, it is always necessary to include samples of other relatives (including the partner) obtained by isolating DNA from a suitable primary material, which is ideally peripheral blood. The examination then proceeds by DNA analysis of the patient and relatives together with amplified embryo DNA using SNP array technology. By detecting fluorescence on a special chip, it is possible to determine the nucleotide composition and therefore the genotype of individual tags (SNPs) at precisely defined positions in the human genome. Approximately 700,000 SNPs covering all chromosomes and the entire genome are used for the analysis. By evaluating the fluorescence intensity in two channels for all SNPs on the chip, information about the genotype and allele ratio between the SNPs and the whole genome is obtained. SNP alleles are transmitted from parents to offspring on the principle of Mendelian inheritance. In the last phase, the obtained SNP data are digitally evaluated by a series of applications in order to obtain informative SNP markers suitable for determining the genotype of the embryo in the gene tested. 

Embryo genotyping is performed using the method of indirect genetic diagnosis, where instead of the mutation itself, SNP markers that are bound to it (on one strand of DNA) are tested. The set of all SNP markers in association with a mutant or normal allele is called a haplotype. To determine the haplotype, SNP markers are used that are evaluated as informative within the framework of a joint SNP analysis of a trio of samples – patient, partner and relative. The basic prerequisite for the correct determination of the haplotype in association with a mutant or normal allele is the correctly determined genotype of the individual based on previous genetic testing and knowledge of relations within the trio. The reliability of embryo genotyping depends on the quality and reliability of the information used for binding analysis. A good quality and reliable reports on the results of genetic testing from an accredited laboratory should be supplied together with a sample of a relative. If no such report is available, appropriate predictive testing should be indicated to determine the genotype of the relative. In the case of an informative result of binding analysis in a trio, it is possible to use a DNA sample of another relative to determine the haplotypes, or to perform direct detection of the mutation in amplified DNA from embryos within PGT-M.