Genetic disorders & infertility in men at a glance
Male infertility can be caused by low sperm production, abnormal sperm function or blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health problems, lifestyle choices and other factors may contribute to male infertility. In some cases, the causes of infertility may not be any of the ones mentioned above; instead, they could be genetically inherited. Some of these include – Klinefelter’s syndrome, cystic fibrosis and Kilmann’s syndrome, amongst others.
Genetic disorders that lead to male infertility
Spermatogenesis is the inability to produce healthy sperm cells. Azoospermia is the medical condition of a man whose semen contains no sperm. This is different from Aspermia – wherein there is neither sperm nor any semen. Causes of Azoospermia include a blockage along the reproductive tract, hormonal problems, ejaculation problems or issues with testicular structure or function. Oligospermia is characterised by a low sperm count in semen. If the sperm count is less than 15 million sperm per millilitre of semen fluid, the condition is called oligospermia. The individual might find it difficult to impregnate a woman.
Klinefelter’s syndrome is a male pattern infertility condition wherein a male is born with two X chromosomes and one Y chromosome instead of one X and one Y chromosome. This leads to the abnormal development of the male reproductive organs. The condition is typically diagnosed around adolescence. Those suffering from the condition are also known to have enlarged breasts syndrome, called gynecomastia.
Cystic fibrosis is a genetically inherited, life-threatening disorder that affects the lungs and the digestive tract. The abnormalities in the cystic fibrosis genes – known as the cystic fibrosis transmembrane conductance regulator are also associated with the absence of the vas deferens causing blockage of the ejaculatory duct or blockage of the epididymis.
Y chromosome infertility is a condition that affects the production of sperm and causes male infertility. This condition makes it difficult for the man to produce mature sperm cells, which leads to a reduction in the number of sperm cells in the seminal fluid or sperm cells that are abnormally shaped or that do not move properly. Men with Y chromosome infertility do not have any other signs or symptoms related to the condition.
Chromosomal abnormality is a genetic disorder wherein a chromosome break and a portion of it reattaches to a different chromosome. Chromosomal translocations can be detected by analysing karyotypes of the affected cells. These Chromosomal translocations are typically seen in cases of leukaemia but also associated with infertility conditions. The chromosomal translocations do not appear to affect semen volume, but translocations appear lower than in fertile men.
Noonan syndrome is a genetic disorder that prevents normal development in various parts of the body. The effects of Noonan syndrome can be exhibited in a wide variety of ways and includes abnormal facial characteristics, short stature, heart defects, other physical problems and possible developmental delays. One of the manifestations of the condition in men would be undescended testicles that cause infertility.
Types of genetic testing for infertility in men
A karyotype genetic test ascertains the size, shape, and number of chromosomes – which should be a pair of 23 or 46 chromosomes in all. This test helps confirm or diagnose a genetic disorder or disease and help ascertain if a couple is at risk of having a child with a genetic or chromosomal disorder. The test is prescribed if you’ve been unable to conceive naturally for a year, have had multiple miscarriages, or have experienced a stillborn birth.
Cystic fibrosis genetic testing looks to ascertain if the cystic fibrosis genes can cause infertility in men. This is confirmed by checking the cells from a blood sample drawn containing the man’s DNA and analysed for CAVD. Most men with congenital absence of vas deferens (CAVD) have at least one mutation that can cause cystic fibrosis. These men and those who produce no sperm, along with their female partners, should undergo genetic testing for cystic fibrosis genes to make sure an offspring would not inherit the disease.
Y chromosome microdeletion is diagnosed by extracting DNA from leukocytes in a man’s blood sample. It also aids in determining the cause of azoospermia or oligospermia and helps predict effectiveness of assisted reproductive technologies in men with Y chromosome microdeletions.