Spath K, Babariya D, Konstantinidis M, Lowndes J, Child T, Grifo JA, Poulton J, Wells D. Clinical application of sequencing-based methods for parallel preimplantation genetic testing for mitochondrial DNA disease and aneuploidy.
Fertil Steril 2021;
115:1521-1532. [PMID:
33745725 DOI:
10.1016/j.fertnstert.2021.01.026]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 12/18/2022]
Abstract
OBJECTIVE
To validate and apply a strategy permitting parallel preimplantation genetic testing (PGT) for mitochondrial DNA (mtDNA) disease and aneuploidy (PGT-A).
DESIGN
Preclinical test validation and case reports.
SETTING
Fertility centers. Diagnostics laboratory.
PATIENTS
Four patients at risk of transmitting mtDNA disease caused by m.8993T>G (Patients A and B), m.10191T>G (Patient C), and m.3243A>G (Patient D). Patients A, B, and C had affected children. Patients A and D displayed somatic heteroplasmy for mtDNA mutations.
INTERVENTIONS
Embryo biopsy, genetic testing, and uterine transfer of embryos predicted to be euploid and mutation-free.
MAIN OUTCOME MEASURES
Test accuracy, treatment outcomes, and mutation segregation.
RESULTS
Accuracy of mtDNA mutation quantification was confirmed. The test was compatible with PGT-A, and half of the embryos tested were shown to be aneuploid (16/33). Mutations were detected in approximately 40% of embryo biopsies from Patients A and D (10/24) but in none from Patients B and C (n = 29). Patients B and C had healthy children following PGT and natural conception, respectively. The m.8993T>G mutation displayed skewed segregation, whereas m.3243A>G mutation levels were relatively low and potentially impacted embryo development.
CONCLUSIONS
Considering the high aneuploidy rate, strategies providing a combination of PGT for mtDNA disease and aneuploidy may be advantageous compared with approaches that consider only mtDNA. Heteroplasmic women had a higher incidence of affected embryos than those with undetectable somatic mutant mtDNA but were still able to produce mutation-free embryos. While not conclusive, the results are consistent with the existence of mutation-specific segregation mechanisms occurring during oogenesis and possibly embryogenesis.
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