In: Biology
How can mutations in different genes be associated with a single disease?
The mutation in different genes are associated with single disease. Such diseases are known as polygenic diseases.
Such phenotype is controlled by more than one gene. For example: diabetes and coronary heart disease etc.
Let's understand it with example. A particular protein which is responsible for a particular phenotype is controlled by more than one genes. This protein has many subunits. And each sub unit is encoded by different genes. These sub units joined together to form a functional protein.
Now, when there is found mutation in any gene, then there is not found wild type sub units formation. In this way,when it is jokned by other subunits, then it can not form functional protein.
Hence mutation in different genes responsible for single disease. Because protein is not found in functional form.
Please look in the image for diagrammatic representation:
Same case for gene 2 and 4 mutations.