O-36: Evaluation of Genetic Variations in Intron 4 and Exon 5 of RABL2B Gene in Infertile Men with Oligoasthenoteratospermia and Immotile Short Tail Sperm Defects
One of the main causes of male infertility is defect in structure and function of sperm cells. Infertile men with oligoasthenoteratospermia (OAT) defect, have sperms with abnormalities in count, motility and morphology. Patients with immotile short tail sperm (ISTS) disorder have immotile short-tailed sperm with disorganized axonem, and a significant decrease in sperm counts. Numerous proteins are involved in sperm formation. One of these proteins is RAB Like 2B (RABL2B), which recently its essential role in fertility in male mouse has been demonstrated. So its gene, which called RAB Like 2B (RABL2B), is an appropriate candidate gene in human studies. Exon 5 of RABL2B gene, codes one of the main domains of the protein and intron 4 is the location for binding of some important transcription factors. The purpose of this study was to evaluate the genetic variations of exon 5 and intron 4 of RABL2B gene in infertile men with OAT and ISTS defects.
Materials and methods
In this study, 30 infertile men with OAT, 30 patients with ISTS and 30 normozospermic men as controls were recruited. To study the genetic variations, DNA was extracted from peripheral blood, and then PCR sequencing was done.
Sequence analysis results did not identify any mutations or single-nucleotide polymorphisms (SNPs) in exon 5, but an intronic variant (rs:144944885), was found in heterozygote form in 5 patients with OAT and one patient with ISTS. No mutation or SNP was identified in controls. Bioinformatics analysis suggested that SRSF7, which is a splicing factor, binds to this part of intron.
Due to the high expression of RABL2B gene in testis, and considering the fact that not many studies have been conducted about the role of this gene in human male fertility, evaluation of other exons and regulatory areas of this gene is recommended.