Identification of TUBB8 Variants in 5 Primary Infertile Women with Multiple Phenotypes in Oocytes and Early Embryos

Tubulin beta 8 class VIII (TUBB8) is a β-tubulin isotype that is specifically expressed in human oocytes and early embryos. It has been identified as a disease-causing gene in primary female infertility by affecting oocyte maturation arrest. This study investigated the genetic cause of female infertility in five patients from four families. Five women with primary infertility were recruited. Medical-exome sequencing and Sanger sequencing were performed on the patients, and their family members to identify candidate genes that explained infertility. Additionally, the morphology of oocytes and zygotes from the patients and controls were assessed. We observed recurrent oocytes MI arrest, oocytes abnormal fertilization, uncleaved embryos, and embryo transfer failure in the patients. Heterozygous missense variants in TUBB8, c.538G > A (p.V180M), c.527C > G (p.S176W), c.124C > G (p.L42V), and c.628A > C (p.I210L), were verified in four unrelated families. This study expanded the mutational spectrum of TUBB8 by identifying three novel heterozygous missense variants. Screening for TUBB8 mutation demonstrated the diagnostic utility of female infertility.