Detecting mosaicism in trophectoderm biopsies: current challenges and future possibilities

Area of Science:

• Reproductive biology
• Genetics
• Assisted reproductive technology

Background:

• Embryonic mosaicism, the presence of distinct cell lines in an embryo, is frequently reported in IVF-derived preimplantation embryos.
• High reported incidences (4-90%) contrast sharply with low rates (<0.5%) in clinical pregnancies, suggesting potential overestimation.

Purpose of the Study:

• To critically review the literature on embryonic mosaicism.
• To propose an alternative interpretation of existing data, considering technical diagnostic variations.
• To discuss future challenges in diagnosing mosaicism for PGD-A.

Main Methods:

• Literature review and critical analysis.
• Exploration of technical variations impacting mosaicism diagnosis.
• Discussion of diagnostic challenges in trophectoderm biopsies.

Main Results:

• The incidence of embryonic mosaicism may be overestimated in preimplantation embryos.
• Technical variations in diagnosing mosaicism contribute to inflated incidence rates.
• Detecting true mosaicism in trophectoderm biopsies remains a significant challenge.

Conclusions:

• Current high estimates of embryonic mosaicism may not accurately reflect true fetal mosaicism rates.
• Improved diagnostic techniques are crucial for accurate mosaicism detection in PGD-A.
• Further research is needed to refine the diagnosis and clinical application of PGD-A.