SYCP2L, a paralogue of the synaptonemal complex protein SYCP2, is expressed exclusively in oocytes. It localizes to centromeres of dictyate stage oocytes and promotes the survival of primordial oocytes, thus being important for female reproductive function [3]. It may also be involved in pathways related to ovarian function and egg production [3,4]. Genetic mouse models have been valuable in studying SYCP2L.

Female mice lacking SYCP2L experience a significantly higher progressive loss of oocytes with age compared to wild-type females, leading to reduced fertility. The pool of primordial oocytes depletes more rapidly in SYCP2L-deficient females, resulting in fewer oocytes maturing in developing follicles [3]. In humans, homozygous variants in SYCP2L have been found to cause premature ovarian insufficiency (POI), with mutant SYCP2L proteins showing mislocalization and loss of function [1]. Additionally, single-nucleotide polymorphisms (SNPs) in SYCP2L are associated with ovarian reserve markers such as anti-Müllerian hormone (AMH) levels and reproductive outcomes in women undergoing in vitro fertilization (IVF) treatment [2,5].

In conclusion, SYCP2L is crucial for female reproductive function, especially in maintaining the survival of primordial oocytes. Studies on SYCP2L-deficient mouse models have provided functional evidence of its role in female reproduction, and human genetic studies have further linked it to POI and other reproductive-related phenotypes. Understanding SYCP2L can potentially lead to better diagnosis and treatment strategies for female infertility.