De Novo Mutation, Preimplantation Genetic Testing, Without Proband
Conditions
Keywords
preimplantation genetic testing, without proband, De Novo Mutation
Brief summary
The clinical practice of PGT-M for monogenetic disease usually adopted a double-checking strategy, which detect the mutation by Sanger sequencing and meantime construct haplotypes using the DNA sample of the proband so as to avoid the risks of misdiagnosis due to recombination and allele drop out (ADO). When there is no affected parent or offspring to serve as the proband, embryo carriers identified through direct mutation detection can be preferentially taken as probands for subsequent linkage analysis. In cases where none of the embryos are detected as mutant carrier, single sperm or the second polar body (PB2) can be complementally collected in the work-up of haplotype establishment. Our study aims to develop an optimized strategy of haplotype construction using gametes or arrested embryos for PGT-M in pedigrees with single gene diseases and no proband in the setting of difficult cases, which takes into account the expected number of oocytes acquired and the gonadal mosaicism.
Interventions
DIAGNOSTIC_TESTGametes (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
Sponsors
ShangHai Ji Ai Genetics & IVF Institute
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Consistence of the PGT-M with prenatal diagnosis with amniocentesis | 16 weeks of gestation | whether the PGT-M result of the embryos are consistent with the prenatal genetic testing result of amniocentesis |
Countries
China
Outcome results
None listed