Infertility can be caused by genetic abnormalities that may affect sperm production or sperm transport. There are three common genetic tests related to male infertility:
- Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene Mutations: This test can determine if you have cystic fibrosis (CF) or are a carrier of the disease. Men with cystic fibrosis typically do not have vas deferens, which is a condition known as congenital bilateral absence of the vas deferens (CBAVD). Testing should also be offered to the female partner in order to identify carriers of CF so couples understand their risk of passing this disease on to their offspring.
- Y-Chromosome Microdeletions (YCMD): This condition is associated with impairment in sperm production. 1 out of the 3 subtypes of YCMDs has the possibility of low amounts of sperm production, while the other 2 subtypes lead to a complete lack of sperm.
- Karyotype: The karyotype test analyzes all chromosomes to check for abnormalities. Extra or missing chromosomes can result in impaired sperm production. An example of this condition is Klinefelter Syndrome, which is characterized by an extra sex chromosome, resulting in XXY rather than XY.
YCMD and karyotype testing should be obtained in all men with fewer than 5 million sperm per mL on semen analysis.