Novel WEE2 gene variants identified in patients with fertilization failure and female infertility.

OBJECTIVE:To determine whether variants in the WEE2 (WEE1 homolog 2, also known as WEE1B) gene, which has been known to function in the formation of pronuclei during fertilization, contribute to fertilization failure. DESIGN:Case-control genetic study. SETTING:University hospital. PATIENT(S):Ninety infertile women with repeated cycles of pronucleus formation failure undergoing in vitro fertilization and/or intracytoplasmic sperm injection treatment as well as 200 fertile control women. INTERVENTION(S):Genomic DNA was extracted from the peripheral blood. The whole exons of WEE2 were amplified by means of polymerase chain reaction and then Sanger sequencing was performed. MAIN OUTCOME MEASURE(S):Variants analysis of WEE2 gene. RESULT(S):We identified five subjects that were subjected to homozygous or compound-heterozygous variants of WEE2: case 1 (from a consanguineous family) with homozygous frameshift variant: c.293_294insCTGAGACACCAGCCCAACC (p.Pro98Pro fsX2); case 2 with homozygous missense variant: c.1576T>G (p.Tyr526Asp); and three cases with compound-heterozygous variants: case 3: c.991C>A (p.His331Asn) and c.1304_1307delCCAA (p.Thr435Met fsX31); case 4: c.341_342 del AA (p.Lys114Asn fsX20) and c.864G>C (p.Gln288His); and case 5: c.1A>G (p.0?) and c.1261G>A (p.Gly421Arg). Besides c.1576T>G (from case 2) and c.864G>C (from case 4), which have been previously reported as rare single nucleotide polymorphisms (SNPs), the other six variants were novel and predicted by software to be deleterious. The parental genotypes of case 1 and case 2 indicated that the detected homozygous variants were inherited in an autosomal recessive mode. All of the detected variants were absent from the control cohort. CONCLUSION(S):Novel variants found in WEE2, which is autosomal-recessive inherited, may be related to recurrent pronucleus formation failure and female infertility.