Mutations in NLRP2 and NLRP5 cause female infertility characterised by early embryonic arrest

Abstract

Background: Successful human reproduction requires normal spermatogenesis, oogenesis, fertilisation and early embryonic development, and abnormalities in any of these processes will result in infertility. Early embryonic arrest is commonly observed in infertile patients with recurrent failure of assisted reproductive technology (ART). However, the genetic basis for early embryonic arrest is largely unknown.

Objective: We aim to identify genetic causes of infertile patients characterised by early embryonic arrest.

Methods: We pursued exome sequencing in a proband with embryonic arrest from the consanguineous family. We further screened candidate genes in a cohort of 496 individuals diagnosed with early embryonic arrest by Sanger sequencing. Effects of mutations were investigated in HeLa cells, oocytes and embryos.

Results: We identified five independent individuals carrying biallelic mutations in NLRP2. We also found three individuals from two families carrying biallelic mutations in NLRP5. These mutations in NLRP2 and NLRP5 caused decreased protein expression in vitro and in oocytes and embryos.

Conclusions: NLRP2 and NLRP5 are novel mutant genes responsible for human early embryonic arrest. This finding provides additional potential diagnostic markers for patients with recurrent failure of ART and helps us to better understand the genetic basis of female infertility characterised by early embryonic arrest.

Keywords: embryonic arrest; female infertility; mutation; reproductive medicine.