M Gentiluomo L Crifasi A Luddi D Locci R Barale P Piomboni D Campa
Human Reproduction, Volume 32, Issue 11, 1 November 2017, Pages 2324–2331, https://doi.org/10.1093/humrep/dex305
Published: 12 October 2017
Are polymorphisms of taste receptor genes associated with male infertility?
This study has showed the associations between three single nucleotide polymorphisms (SNPs) in taste receptors genes (TASR) and male infertility.
WHAT IS KNOWN ALREADY
Recent studies showed the expression of taste receptors in the testis and in spermatozoa, suggesting their possible role in infertility. The vast genetic variability in taste genes results in a large degree of diversity in various human phenotypes.
STUDY DESIGN, SIZE, DURATION
In this study, we genotyped 19 SNPs in 12 taste related genes in a total of 494 Caucasian male patients undergoing semen evaluation at the Centre of Couple Sterility of the Siena University Hospital. Consecutive patients were enrolled during infertility investigations from October 2014 to February 2016.
PARTICIPANTS/MATERIALS, SETTING, METHODS
Median age of the patients was 36 years (18–58) and 141 were smokers. Genotyping was performed using the allele-specific PCR. The statistical analysis was carried out using generalized linear model (GLM) to explore the association between age, smoking, the genetic polymorphisms and sperm parameters.
MAIN RESULTS AND THE ROLE OF CHANCE
We observed that the homozygous carriers of the (G) allele of the TAS2R14-rs3741843 polymorphism showed a decreased sperm progressive motility compared to heterozygotes and (A) homozygotes (P = 0.003). Moreover, the homozygous carriers of the (T) allele of the TAS2R3-rs11763979 SNP showed fewer normal acrosome compared with the heterozygous and the homozygous carriers of the (G) allele (P = 0.002). Multiple comparisons correction was applied and the Bonferroni-corrected critical P-value was = 0.003.
LIMITATIONS, REASONS FOR CAUTION
The analysis is restricted to SNPs within genes and to men of Caucasian ancestry.
WIDER IMPLICATIONS OF THE FINDINGS:
In silico analyses strongly point towards a functional effect of the two SNPs: TAS2R14-rs3741843 regulates TAS2R43 expression, a gene that is involved in cilia motility and therefore could influences sperm mobility; the (T) allele of TAS2R3-rs11763979 increases the expression of the WEE2 antisense RNA one gene (WEE2-AS1). According to Genotype-Tissue Expression (GTEx) project the WEE2 gene is expressed in the testes where presumably it has the role of down regulating meiotic cell division. It is plausible to hypothesize that the WEE2-AS1 increased expression may down regulate WEE2 which in turn can alter the natural timing of sperm maturation increasing the number of abnormal sperm cells.
STUDY FUNDING/COMPETING INTEREST(S)
Keywords: SNPs, male infertility, taste receptors, spermatozoa, semen parameters