MALE INFERTILITY – POSSIBLE GENETIC CAUSES
There are many reasons for infertility in males and one possible cause is Genetic. The most common genetic cause is due to chromosome conditions which affect the way that sperm is produced.
Klinefelter Syndrome: Normally, a man has an XY chromosome and, when he has an extra X-chromosome, it is known as Klinefelter Syndrome. People who have this may have very low sperm count or no sperm at all in their semen. Their testosterone levels will also be lower than average. This problem is fairly common and may lead to infertility. However, sometimes, they may have sperm in their testicles and, if so, then it can be extracted and used to fertilize the female partner’s egg through the ICSI procedure (intracytoplasmic sperm injection).
Y Chromosome Microdeletions (YCM): These are genetic disorders caused by missing gene(s)in the Y chromosome. Many men with this disorder show no symptoms and lead normal lives. However, some men with reduced fertility have this YCM. It passes from father to son and any male child born to a man with YCM will also have the same disorder. Female children do not have the Y chromosome at all and so are not affected.
Cystic Fibrosis Gene Mutation: A mutation in a single gene can cause cystic fibrosis when the specific protein is made incorrectly due to the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. This can lead to reproductive problems, among many others as well. Though most men who have this condition are able to produce sperm naturally, they are born without the tube that carries the sperm from the testicles to the urethra (the vas deferens). If the woman also has a cystic fibrosis gene mutation, then the child may be at risk and it is better if both the male and female are checked for this. If it is only the male who is affected, it is possible to use ICSI to extract sperm and fertilise the woman’s eggs. The CFTR gene mutation can also cause obstructive azoospermia, where the male reproductive tract is blocked, leading to the ejaculate having no sperm at all.
Chromosomal aneuploidy: is having an abnormal number of chromosomes or an alteration in chromosomal numbers from the normal. Although to date, not much is known about aneuploidy affecting fertility, it is felt that an elevated sperm aneuploidy rate does result in fertility problems.
Autosomal chromosomes: There are 2 types of chromosomes – one the sex chromosome which determines whether a child is male or female and all the others are autosomal chromosomes. One of the disorders when an autosomal dominant inheritance causes a copy of an altered gene is Noonan syndrome. Most males with this disorder have Cryptorchidism, where one or both of the testes is/are undescended and fail to enter the scrotum from the abdomen. This may contribute to male infertility.
Since there is now technology to try and overcome fertility issues, like the ICSI, it is very important that the cause of the infertility be analyzed. If it is due to a genetic disorder, it is recommended that the couple seek genetic counseling, which will help them with the options available and to decide on which one will be the best for them.