Embryo genome profiling by single-cell sequencing for successful preimplantation genetic diagnosis in a family harboring COL4A1 c.1537G>A; p.G513S mutation.

CONTEXT: Genetic profiling of embryos (also known as preimplantation genetic diagnosis) before implantation has dramatically enhanced the success quotient of in vitro fertilization (IVF) in recent times. The technology helps in avoiding selective pregnancy termination since the baby is likely to be free of the disease under consideration.

AIM: Screening of embryos free from c.1537G>A; p.G513S mutation within the COL4A1 gene for which the father was known in before be in heterozygous condition.

SUBJECTS AND METHODS: Processing of trophectoderm biopsies was done from twelve embryos for c.1537G>A; p.G513S mutation within the COL4A1 gene. DNA extracted from isolated cells were subjected to whole genome amplification using an isothermal amplification and strand displacement technology. Oligonucleotide primers bracketing the mutation were synthesized and used to amplify 162 base pairs (bp) polymerase chain reaction amplicons originating from each embryo which were subsequently sequenced to detect the presence or absence of the single base polymorphism.

RESULTS: Three out of 12 embryos interrogated in this study were found to be normal while 9 were found to harbor the mutation in heterozygous condition. Implantation of one of the normal embryos following by chorionic villus sampling at 11(th) week of pregnancy indicated that the baby was free from c.1537G>A; p.G513S mutation within the COL4A1 gene.

CONCLUSIONS: Single-cell sequencing is a helpful tool for preimplantation embryo profiling. This is the first report from India describing the birth of a normal child through IVF procedure where a potential pathogenic COL4A1 allele was avoided using this technology.