Early embryonic failure caused by a novel mutation in the TUBB8 gene: A case report

Table 1 Description and characteristics of assisted reproductive technology cycles

	Cycle 1	Cycle 2	Cycle 3	Cycle 4	Cycle 5
COH protocol	GnRH-A Long	GnRH-Ant	Natural cycle	Luteal phase	Natural cycle
Gonadotropin	r-FSH	r-FSH	-	HMG	-
Initiation dose (IU)	200	225	-	225	-
Total dose of gonadotropin (IU)	1975	2025	-	2025	-
Duration of gonadotropin (d)	9	9	-	9	-
E2 level on the day of HCG injection	6605.24	5822.55	189.60	2239.37	172.30
LH level on the day of HCG injection	1.54	0.57	4.87	1.86	4.04
P level on the day of HCG injection	2.05	2.56	0.28	7.38	0.21
No. of follicles (≥ 18 mm)	3	6	0	4	0
No. of follicles (≥ 14 mm)	9	8	1	8	1
Ovulation trigger (dose)	6000 IU (HCG)	2000 IU (HCG) + 0.2 mg (GnRH agonist)	0.1 mg (GnRH agonist)	6000 IU (HCG)	0.1 mg (GnRH agonist)
Interval between HCG administration and oocyte retrieval (h)	35.5 h	35 h	35 h	35 h	34 h
Number of retrieved oocytes	12	15	1	12	1
Fertilization mode	R-ICSI	ICSI	ICSI	ICSI	-
No. of MII	8	13	0	11	0
No. of GV	2	1	0	0	-
No. of 2PN	5	10	-	8	-
No. of D2 zygote	5	10	-	8	-
No. of D3 embryos	5	7	-	6	-
No. of blastocysts	0	0	-	0	-
No. of transferred embryos	1 (FET)	-	-	-	-
Pregnancy outcome	Not pregnant	No transferable embryos	No transferable embryos	No transferable embryos	No transferable embryos

COH: Controlled ovarian hyperstimulation; MII: Metaphase II; MI: Metaphase I; GV: Germinal vesicle; 2PN: 2 pronucleus; FET: Frozen Embryo Transfer.

Table 2 Results of sequencing mutation sites in the coding region of the TUBB8 gene in the patient (female)

Gene	Chromosomal location	Variant naming	Frequency	Zygotic type	Source of variation
TUBB8	Chr 93730	NM_177987.3: c.602G>T(p.C201F)	Not included	Heterozygous	Unknown

Remarks: The variation verification result may be the complementary sequence of the reference sequence, and the variation C>A can also be expressed as G>T.

Table 3 Results of mutation site verification in the patient's parents

Relationship	Gene	Transcript	Verification site	Verification results
Father	TUBB8	NM_177987.3	c.602G>T	Heterozygous variation
Mother	TUBB8	NM_177987.3	c.602G>T	Without-variation