Achieving an optimal pregnancy outcome through the combined utilization of micro-TESE and ICSI in cryptorchidism associated with a non-canonical splicing variant in RXFP2.

PURPOSE: To identify the genetic cause of a cryptorchidism patient carrying a non-canonical splicing variant highlighted by SPCards platform in RXFP2 and to provide a comprehensive overview of RXFP2 variants with cryptorchidism correlation.

METHODS: We identified a homozygous non-canonical splicing variant by whole-exome sequencing and Sanger sequencing in a case with cryptorchidism and non-obstructive azoospermia (NOA). As the pathogenicity of this non-canonical splicing variant remained unclear, we initially utilized the SPCards platform to predict its pathogenicity. Subsequently, we employed a minigene splicing assay to further evaluate the influence of the identified splicing variant. Microdissection testicular sperm extraction (micro-TESE) combined with intracytoplasmic sperm injection (ICSI) was performed. PubMed and Human Genome Variant Database (HGMD) were queried to search for RXFP2 variants.

RESULTS: We identified a homozygous non-canonical splicing variant (NM_130806: c.1376-12A > G) in RXFP2, and confirmed this variant caused aberrant splicing of exons 15 and 16 of the RXFP2 gene: 11 bases were added in front of exon 16, leading to an abnormal transcript initiation and a frameshift. Fortunately, the patient successfully obtained his biological offspring through micro-TESE combined with ICSI. Four cryptorchidism-associated variants in RXFP2 from 90 patients with cryptorchidism were identified through a literature search in PubMed and HGMD, with different inheritance patterns.

CONCLUSION: This is the first cryptorchidism case carrying a novel causative non-canonical splicing RXFP2 variant. The combined approach of micro-TESE and ICSI contributed to an optimal pregnancy outcome. Our literature review demonstrated that RXFP2 variants caused cryptorchidism in a recessive inheritance pattern, rather than a dominant pattern.