Preimplantation Genetic Testing for Monogenic Disease of Spinal Muscular Atrophy by Multiple Displacement Amplification: 11 unaffected livebirths

Abstract

Background: Preimplantation genetic testing for monogenic disease (PGT-M) has become an effective method for providing couples with the opportunity of a pregnancy with a baby free of spinal muscular atrophy (SMA). Multiple displacement amplification (MDA) overcomes the innate dilemma of very limited genetic material available for PGT-M.Objective: To evaluate the use of MDA, combined with haplotype analysis and mutation amplification, in PGT-M for families with SMA.Methods: MDA was used to amplify the whole genome from single blastomeres or trophectoderm (TE) cells. Exon 7 of the survival motor neuron gene 1 (SMN1) and eleven STRs markers flanking the SMN1 gene were incorporated into singleplex polymerase chain reaction (PCR) assays on MDA products.Results: Sixteen cycles (19 ovum pick-up cycles) of PGT-M were initiated in 12 couples. A total of 141 embryos were tested: 90 embryos were biopsied at the cleavage stage and 51 embryos were biopsied at the blastocyst stage. MDA was successful on 94.44% (85/90) of the single blastomeres and on 92.16% (47/51) of the TE cells. And the PCR efficiency were 98.4% (561/570) and 100% (182/182), respectively. In addition, the average allele drop-out (ADO) rates were 13.3% (60/392) and 9.8% (11/112), respectively. The results for SMN1 exon 7 were all matched with haplotype analysis, which allowed an accurate diagnosis of 93.62% (132/141) embryos. Twelve families had unaffected embryos available for transfer and a total of 38 embryos were transferred in 20 embryo transfer cycles. Eight transfers were successful, resulting in a clinical pregnancy rate of 40% (8/20) and an implantation rate of 28.95% (11/38). Finally, 11 healthy babies were born. Among them, 5 SMA carriers were singleton live births and 3 SMA carriers had twin births.Conclusion: Careful handling during the MDA procedure can improve subsequent PCR efficiency and reduce the ADO rate. We suggest that this protocol is reliable for increasing the accuracy of the PGT-M for SMA.

Preimplantation Genetic Testing Prevented Intergenerational Transmission of X-Linked Alport Syndrome

“…Furthermore, ADO usually causes disastrous false-negative results [35]. NGS that is based on SNP markers has now been used to improve the accuracy of PGT-M [36]. The capture sequencing and linkage analysis of SNPs located near the gene of interest allow a convenient and efficient approach to the experimental design of PGT-M [35].…”

In Vitro Fertilization Using Preimplantation Genetic Testing in a Romanian Couple Carrier of Mutations in the TTN Gene: A Case Report and Literature Review

“…Preimplantation genetic testing using karyomapping has proven its usefulness in obtaining healthy embryos and subsequent successful pregnancies in which myotonic dystrophy type I (MDI) [ 22 , 23 , 24 , 25 ], Duchenne muscular dystrophy (DMD) [ 26 , 27 ], muscular atrophy [ 28 ] are avoided. This approach has also been applied effectively for averting the consequences of other genetic events such as reciprocal translocation [ 29 ] and dynamic mutation [ 30 ].…”

Novel Compound Heterozygous Mutations in CRTAP Cause Rare Autosomal Recessive Osteogenesis Imperfecta

“…The expanded carrier screening is of importance to identify such variants in couples before pregnancy. Once the couples are found to be at risk for transmitting certain types of diseases, in vitro fertilization and preimplantation genetic testing (PGT) for monogenic disorders may be considered to stop transmitting deleterious variants into the next generation ( Daar et al, 2018 ; Fu et al, 2019 ; van der Schoot et al, 2019 ).…”