NEXT GENERATION SEQUENCING, NGS
Analysis of embryo genome
PREIMPLANATION GENETIC TESTING NGS
THE PROBABILITY OF PREGNANCY WITH PGD NGS
STUDY OF CHROMOSOMES
The criterion for prescription – increased risk of chromosomal or genetic disease. The goal of PGT-a is to identify embryos without specific genetic pathology (genetic or chromosomal). As a result, the diagnosis significantly increases the chances of pregnancy, reduces the number of non-productive IVF cycles and preserves the health of the woman (due to the decrease in the volume of hormones taken).
HISTORY OF NGS IN THE WORLD AND NGC
- 2014 - the birth of the first child after IVF with PGT-a using the method NGS (UK)
- 2016 – Saint-Petersburg – the birth of first children surveyed at the stage of the embryo by the method of NGS
- 2017 - more than 300 tests per year on 1000 embryos. About 300 embryos of them are in high probability of euploidy - in the cryopreservation stage.
METHODS OF CHROMOSOME ANALYSIS AT THE EMBRYONIC STAGE OF EMBRYO TESTING
- FISH analysis (one cell)
- PCR (polymerase chain reaction)
- arrCGH (Comparative genomic hybridization on microchips)
- MPS (massive parallel DNA sequencing (MPS/NGS) of multiple cells)
HISTORY OF EMBRYO RESEARCH
MEDICAL-GENETIC PROGNOSIS FOR EMBRYO, FETUS AND CHILD
ANALYSIS OF THE NUMBER OF CHROMOSOMES BY THE METHOD OF NGS – NORM AND MULTIPLE DISORDERS.
- The probability of development of an embryo (pregnancy)
- The probability of developmental disorders of the embryo
- The probability of severe morphological disorders of fetal development
- The probability of detection of phenotypic abnormalities in the fetus using ultrasound investigation
- The probability of disorders in the neonatal period
- The probability of mental retardation, cognitive disorders, multisystem somatic disorders
- Quality of life and health of both child and family
Application of methods of advanced analysis of the genome provides a comprehensive prognosis of the implementation of the genetic status at all stages of ontogeny the embryo-fetus-child and is the basis for decision-making about embryo transfer in ART programs.
TASKS THAT PGS HELPS TO SOLVE
- REDUCING THE NUMBER OF"FRUITLESS TRANSFERS".
- REDUCING THE RISK OF SPONTANEOUS ABORTION.
- INCREASED CHANCES OF PREGNANCY IN PATIENTS AT RISK (LATE AGE, CARRIER TRANSLOCATIONS, MULTIPLE FAILED IVF ATTEMPTS).
- BIRTH OF A HEALTHY CHILD AT RISK OF MONOGENIC PATHOLOGY
- REDUCING THE RISK OF CHROMOSOMAL ABNORMALITIES IN THE CHILD
- REDUCING THE RISK OF RHESUS-CONFLICT
- TREATMENT OF DISEASED SIBS (HISTOCOMPATIBILITY SELECTION)
HIGHER CHANCE OF IVF PREGNANCY
(UP TO 65% - GENERAL GROUP, 69% - SENIOR REPRODUCTIVE AGE)
THE TRANSFER OF ONLY ONE EMBRYO WITH A HIGH CHANCE OF PREGNANCY INCREASES THE PROBABILITY OF SUCCESSFUL GESTATION, THERE IS NO RISK OF TWINS
ELIMINATING THE RISK OF HAVING A BABY WITH CHROMOSOMAL SYNDROMES
REDUCING THE RISK OF ABORTION DUE TO FETAL PATHOLOGY
WHAT IS DIFFERENT BETWEEN PGD, PGS AND PGT?
Targeted analysis of individual chromosomes or genes – monogenic diseases.
Study of chromosomal abnormalities (number and structure of chromosomes)..
Complex combined analysis - exclusion of individual pathology and accidental disorders. For example, the analysis of translocation and estimation of the number of chromosomes in the analysis of single gene and chromosomes.
We carry out PGS of embryos and PGD not only for couples who want to get pregnant, but also for donors
STAGES OF PGS
To whom is PGS recommended?
Pre-implantation genetic testing can be used for different groups of patients:
- Parents who are carriers of hereditary chromosomal diseases and do not want to transmit these diseases to their child.
- After a couple of setbacks when attempting pregnancy in a natural way.
THE MOST COMMON METHOD OF EMBRYO SELECTION IS BASED SOLELY ON THEIR MORPHOLOGY – THERE IS NO CORRELATION BETWEEN THE MORPHOLOGICAL AND CHROMOSOMAL STATUS OF THE EMBRYO
THE QUALITY OF THE EMBRYO 5AB, XXY
QUALITY 5AA, MISSING 18 AND DOUBLED 7 CHROMOSOMES
4BB, MISSING CHROMOSOME 22
FREQUENCY OF CHROMOSOMAL ABNORMALITIES
THE RISK OF CHROMOSOMAL ABNORMALITIES IS IN ALL EMBRYOS IN ALL FAMILIES - THE FREQUENCY OF CHROMOSOME ABNORMALITIES OF THE EMBRYO INCREASES WITH THE AGE OF THE MOTHER.
FERTILITY AND FREQUENCY OF
SPONTANEOUS ABORTIONS DEPENDING ON WOMEN'S AGE
ART / IVF - taking into account the biological status of the embryo does not give:
- Guarantee of pregnancy;
- Guarantee of continuation of pregnancy;
- Guarantee the birth of a child;
- Guarantee of a healthy child.
IVF does not reduce the risks of chromosomal abnormalities and monogenic diseases.
IVF as a method of infertility treatment does not make it possible to increase the probability of having a healthy child.
ART / IVF is performed in groups of population, increased and high risks of offspring pathology.
OUR RESULTS ON COMPREHENSIVE CHROMOSOME EMBRYO TESTING BASED ON NGS FOR THE BEGINNING OF 2017
For each embryo it was determined:
- Prognosis of embryo development (pregnancy);
- Prenatal prognosis;
- Postnatal prognosis;
- Recommendations for examination of the fetus before and after birth.
NGS WAS PERFORMED FOR 1355 EMBRYOS
trisomy on one chromosome
single chromosome monosomy
mosaic forms of aneuploidies
multiple - mosaic and full of aneuploidies
no deviations were found (recommended for transfer)
Genetic conclusion for each embryo
- Probability of pregnancy
- Probability of pregnancy by trimesters
- Fetal prognosis
- The necessity and feasibility of PGD
- Probability of chorion – placental disorders
- Postnatal prognosis
FREQUENTLY ASKED QUESTIONS (FAQ):
Classical genetic analysis reveals the changed number of chromosomes and large structural disorders. It cannot be used for embryo cells.