The clinical practice of PGT-M for monogenetic disease usually adopted a double-checkingstrategy, which detect the mutation by Sanger sequencing and meantime constructhaplotypes using the DNA sample of the proband so as to avoid the risks of misdiagnosisdue to recombination and allele drop out (ADO). When there is no affected parent oroffspring to serve as the proband, embryo carriers identified through direct mutationdetection can be preferentially taken as probands for subsequent linkage analysis. Incases where none of the embryos are detected as mutant carrier, single sperm or thesecond polar body (PB2) can be complementally collected in the work-up of haplotypeestablishment. Our study aims to develop an optimized strategy of haplotype constructionusing gametes or arrested embryos for PGT-M in pedigrees with single gene diseases and noproband in the setting of difficult cases, which takes into account the expected numberof oocytes acquired and the gonadal mosaicism.
Not Provided
Diagnostic Test: Gametes (sperm or second polar bodies, MI eggs) or arrested embryos were reserved for identification of a proband
1. Targeted deep sequencing for mosaicism detection for patients with suspected gonadal
mosaicism, eg. Repeated similar abortion due to the same variant while the couple
were tested negative for the variant in the peripheral blood.
2. Ovarian stimulation, embryo culture, biopsy and vitrification as routinely used in
the IVF clinical practice.
3. Gametes and arrested embryo preservation by the embryo laboratory during embryo
culture.
4. Genetic testing, including multiple displacement amplification for WGA, variant
sequencing in WGA products and Infinium Chip protocol for amplified DNA and
haplotype analysis
Other Name: Targeted deep sequencing for mosaicism detection,Ovarian stimulation, embryo culture, biopsy and vitrification,Genetic testing
Inclusion Criteria:
- The couples intended for PGT-M without proband were recruited from Shanghai JiAi
Genetics and IVF Institute, Obstetrics and Gynecology Hospital of Fudan University
between January 2023 and December 2024, and were included in the study if they were
expected to have difficulties in the identification of an EAP, typically meeting one
of the following criteria:
1. the carrier of the pathogenic variant was without typical clinical symptoms or
detected as gonadosomal mosaic;
2. the asymptomatic parents, who had one or more children affected with the same
disorder, did not possess the genomic alterations carried by the children as
per Sanger sequencing or targeted deep sequencing;
3. female partner with diminished ovarian reserve and therefore a low yield of
embryos;
4. the variants are X-linked and the karyotype of the variant carrier is 47, XXX
or 47, XXY etc.
Exclusion Criteria:
- (1) Non-PGT-M families; (2) Pedigree of other proband samples can be obtained; (3)
Patients seeking for PGT-M who strongly request no haplotype analysis in embryos and
only require Sanger testing after being fully informed of the risk.
Shanghai Ji Ai Genetics and IVF Institute, Obstetrics and Gynecology Hospital, Fudan University
Shanghai, Shanghai, China
Yilun Sui, MD, Principal Investigator
Shanghai Ji Ai Genetics and IVF Institute, Obstetrics and Gynecology Hospital, Fudan University