JBRA Assisted Reproduction 2025;29(Suppl.2 SBRA 2025):164
Poster Presentation
29^th Annual Congress of the SBRA. São Paulo/SP - Brazil, 2025
doi: 10.5935/1518-0557.20263925

P-152. Live Birth After Transfer of an NF1-Screened Embryo with Partial Monosomy of Chromosome 10: A Case Report

Juliana Polisseni¹, Cristina Valletta de Carvalho¹, Larissa Milani Coutinho¹, Hugo Toledo Vitoi¹

¹ Clinica NIDUS - Juiz de Fora - MG – Brasil

Objective: The transfer of embryos with partial monosomy has become a subject of debate due to their potential to result in viable pregnancies. We report a case of successful pregnancy and healthy live birth following the transfer of an embryo carrying a partial monosomy of chromosome 10
Methods: A 37-year-old woman and a 44-year-old man sought fertility treatment. The woman presented with a normal ovarian reserve and patent fallopian tubes. The male partner had a clinical diagnosis of neurofibromatosis type 1 (NF1), and the couple's first child, aged five, was already exhibiting early clinical signs of the disease. Neurofibromatosis type 1 is an autosomal dominant disorder characterized by pigmentary changes of the skin and the development of tumors along peripheral and central nerves. It is caused by pathogenic variants in the NF1 gene, which encodes neurofibromin, a protein expressed in various cell types, including neurons and glial cells such as oligodendrocytes and Schwann cells. The clinical presentation of NF1 is highly variable, even within the same family. Almost all affected individuals develop multiple café-aulait macules in early childhood, which increase in size and number over time. Axillary and inguinal freckling typically emerges later in childhood. Most adults develop cutaneous or subcutaneous neurofibromas, and tumors may also arise along deeper nerve structures. Malignant peripheral nerve sheath tumors occur in a subset of cases.
Results: After genetic counseling, it was estimated that only one in eight to ten embryos would be free of NF1. The couple underwent intracytoplasmic sperm injection (ICSI) with combined preimplantation genetic testing for monogenic disease (PGT-M) targeting the NF1 mutation and preimplantation genetic testing for aneuploidy (PGT-A). Controlled ovarian stimulations were performed across four in vitro fertilization (IVF) cycles. • Cycle 1: Seven mature oocytes were inseminated, yielding four blastocysts, all affected by NF1 according to PGT-M/PGT-A. • Cycle 2: Seven mature oocytes were cryopreserved. • Cycle 3: Six fresh oocytes plus the seven frozen oocytes from cycle 2 (total of 13) were inseminated, producing five blastocysts. • Cycle 4: Eight mature oocytes were inseminated, producing five blastocysts. Among the ten blastocysts analyzed from cycles 3 and 4, four were unaffected by NF1. Of these, one was euploid and transferred but did not result in pregnancy. Another embryo unaffected by NF1 demonstrated a partial monosomy on the long arm of chromosome 10 (10q21.2–q26.3) on PGT-A, involving an approximately 73 Mb deletion encompassing ~1,344 genes. Although no previous live births with this specific genomic alteration had been reported, genetic counseling concluded that the transfer posed a low predicted risk to fetal development. This embryo was transferred, resulting in an uneventful pregnancy and the birth of a healthy female infant with a normal peripheral blood karyotype.
Conclusion: The transfer of embryos with partial monosomy remains a matter of clinical and ethical discussion. This case illustrates that certain large-scale chromosomal deletions may not necessarily impair fetal viability or development, emphasizing the need for individualized counseling and careful genomic interpretation in assisted reproduction.