Gene, protein and disease

Associations between genes (DNA and RNA) and proteins, which can be targeted as biomarkers, and diseases is explained below.
DNA exists in the nucleus of cells that constitute the human body. mRNA is transcripted from DNA, and proteins are translated from mRNA. Proteins directly act in life phenomena, and there are about 30,000 different types of proteins.
If the amount of proteins changes due to external factors, humans become ill.
Many diseases are thus caused by a change in amount of RNA and proteins, and it is said that diseases can be diagnosed by detecting changes using RNA and proteins as markers.
As shown in the figure below, because the change (abnormality) in RNA precedes that in protein, it is said that RNA can be used for earlier detection of change in status such as diseases.

Proteins are responsible for most aspects of life phenomena.
"Genes(DNA)"="Blueprint of proteins"="Blueprint of life"