Genetic abnormalities can cause infertility by affecting sperm production or transport from the testicle to the semen. Three common genetic tests related to male infertility are:
- Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene Mutations: Men with congenital bilateral absence of the vas deferens (CBAVD), which is when both vas deferens do not develop, should be tested for cystic fibrosis.
- Karyotype: This test analyzes all chromosomes to see if there are any extra or missing chromosomes, which can result in impaired sperm production. An example is Klinefelter Syndrome (KS), in which a man has an extra sex chromosome, so they have XXY instead of XY.
- Y-Chromosome Microdeletions (YCMD): associated with spermatogenic impairment. In the case of CBAVD, the patient and female partner should be offered testing and counseling to identify carriers of cystic fibrosis (CF), as this may have implications for future offspring.
Men with less than 5 million sperm per mL on semen analysis should be offered karyotyping and Y-chromosome analysis.