Novel splicing mutations in PATL2 and WEE2 cause oocyte degradation and fertilization failure.

PURPOSE: To determine the genetic cause of infertility in two unrelated families of female patients suffering from oocyte degeneration and fertilization failure.

METHODS

Whole exome sequencing and Sanger sequencing were performed to identify the disease-causing genes of infertility in two unrelated female patients. Minigene experiments were conducted to confirm the effect of splice site mutations on mRNA splicing.

RESULTS

In two unrelated female infertility patients, a novel compound heterozygous splicing mutation (c.516-1G > T and c.877-1G > A) in PATL2 gene and a novel homozygous splicing mutation (c.1222-1G > A) in WEE2 gene were identified. Minigene splicing assays revealed that the c.516-1G > T mutation in PATL2 resulted in a deletion of 8 bases in mRNA that causes a frameshift (c.516-523delTCCCCCAG, p.P173Q fs*13). The c.877-1G > A mutation led to the skipping of exons 10 and 11 and retention of introns 8-9 in PATL2 mRNA. The c.1222-1G > A mutation resulted in the deletion of exon 9 in WEE2 mRNA, leading to an in-frame deletion of 57 amino acids in the WEE2 protein (p.408-464del).

CONCLUSION

Our study discovered novel splicing mutations in PATL2 and WEE2, further expanding the mutation spectrum of these two genes and providing guidance for genetic counseling and diagnosis of female infertility.