Some genetic diseases, due to the way in which they are inherited or passed on, may only affect mothers and sons.
This occurs when a genetic disease is inherited in an X-linked recessive pattern. If a Mother carries a gene mutation or change (known to cause a rare disease) on one of her two X chromosomes and then passes it on to her son, she is in effect passing the rare disease down a generation. This occurs because male children inherit their X chromosome from their mother and their Y chromosome from their father. Female children have two X chromosomes, and they receive a copy of each from each parent.
If a Mother is a carrier of a gene mutation on the X chromosome, she has a 50% chance of that gene change down to each and every single son that she has. She also has a 50% chance of passing the same X-linked gene change to her daughters, but they will generally only be carriers (like their mother) because the unaltered X chromosome they receive from their Father will balance the mutated one out.
A father who carries this same X-linked gene mutation down to his daughters will have daughters who are carriers and may then in turn pass this gene change to their children. Fathers can not pass an X-linked genetic disease down to their sons.
Examples of genetic diseases passed from mother to son
Common genetic conditions passed from mother to son include red-green color blindness and hemophilia A.
- Alport syndrome – when inherited in an X-linked pattern, this genetic disease affects mainly males. Common symptoms include eye abnormalities and progressive hearing loss.
- Barth syndrome – this rare, metabolic genetic disease has been diagnosed in just 150 individuals to date, according to the most updated figures. The main and most serious symptom of this syndrome is an enlarged and consequently weakened heart. Life expectancy may be shortened.
- Coffin-Lowry syndrome – this genetic disease includes severe mental and intellectual disability among its main symptoms. It also presents with complicated health conditions including cardiac, growth, visual, and hearing issues.
- Fabry disease – this rare genetic disease is a lysosomal storage disorder, the symptoms of which are triggered by an abnormal build-up of a specific type of fat within the body. The main symptoms of this genetic disease include periods of pain, skin rashes, and an inability to sweat.
Genetic counseling
When it comes to understanding genetic diseases passed from mother to son, the best expert to consult with is a genetic counselor. Genetic counselors are trained to understand the many different ways in which genetic diseases are passed from parents to their children. They can advise parents who are known carriers of a genetic mutation, and one known to be inherited in an X-linked manner, on what their genetic health status might mean for the health of their future children.
It is important to schedule a one-on-one session with a genetic counselor to get the right information for treating and detecting certain rare genetic diseases including 3MC syndrome and others.
