If an organism did not have casein as a protein, it would likely have a number of health problems. For example, casein is essential for the proper absorption of calcium, and without it, the body would not be able to get enough calcium from food. This could lead to a number of health problems, including osteoporosis, weak bones, and muscle cramps.
In addition, casein is also important for the proper functioning of the immune system. It helps to protect the body from infection, and without it, the body would be more likely to get sick.
Finally, casein is also important for the proper development of the brain and nervous system. Without it, children would be more likely to have developmental problems, such as mental retardation and learning disabilities.
In short, casein is an essential protein for the proper functioning of the human body. Without it, organisms would likely have a number of health problems.