The disease varies in severity based on the nature of the amino acid changes. Collagen is also found in the skin, ligaments, and tendons and lesser forms of the disease cause problems with these tissues. In severe forms of the disease, the bones are malformed. Hemophilia Hemophilia A is an X-linked disease seen in 1 in 10,000 males. Inactive clotting proteins lead to problems even with a minor cut because the bleeding is difficult to stop.
Multifactorial diseases are more common.
In multifactorial diseases, more than one gene and more than one protein interact with environmental factors to cause problems. These parents are also called carriers . The offspring have to be homozygous recessive to have the disease or condition. The enzymes compensate for the missing protein by doing more work than normal. When they are exposed to lower oxygen levels, they will experience some of the symptoms of the individual with sickle-cell disease.