Wednesday, June 27, 2012

Genes and diseases

Human cell contains 46 chromosomes (22 pairs of autosomal chromosomes and 2 sex chromosomes) between them are approximately 3 billion base pairs of DNA that encloses about 30,000 - 40,000 protein-coding genes. The coding regions make up less than 5% of the genome (the function of the remaining DNA is unclear) and some chromosomes have a higher density of genes than others.

Most of the genetic disorders featured so far are the direct result of a mutation in one gene. Conversely, one of the most difficult problems ahead is to find out how genes contribute to diseases with complex pattern of inheritance, like in the cases of diabetes, asthma, cancer and mental illness. In all these cases, no single gene contributed but combination of genes to be altered to manifest the disorder, and a number of genes may each make a subtle contribution to a person's susceptibility to a disease and respond variably in a particular environment.

Blood and Lymph Diseases

Most of the cells in the human body are not in direct contact with the external environment, the circulatory system acts as a transport system for these cells. Two distinct fluids move through the circulatory system: blood and lymph.

Blood carries oxygen, hormones, antibodies and nutrients to the body's cells, and carries waste materials away. The heart is the pump that keeps this transport system moving. Together, the blood, heart, and blood vessels form the circulatory system.

The lymphatic system (lymph, lymph nodes and lymph vessels) maintains the circulatory system by draining excess fluids and proteins from tissues back into the bloodstream, in this manner preventing tissue swelling. It also serves as a defense system for the body, filtering out pathogens by producing white blood cells, and generating antibodies.


• Anemia, sickle cell

• Burkitt lymphoma

• Gaucher disease

• Hemophilia A

• Leukemia, chronic myeloid

• Niemann-Pick disease

• Paroxysmal nocturnal hemoglobinuria

• Porphyria

• Thalassemia

The Digestive System

Digestion is the process of converting food into fuel for energy, and for upholding of the body structure. The digestive tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus. Inside this tube is a lining known as mucosa. In the mouth, stomach, and small intestine, the mucosa contains tiny glands that secrete enzymes to facilitate digest food. There are also two solid digestive organs, the liver and the pancreas, which produce enzymes that reach the intestine through small tubes.


• Colon cancer

• Crohn's disease

• Cystic fibrosis

• Diabetes, type 1

• Glucose galactose malabsorption

• Pancreatic cancer

• Wilson's disease

• Zellweger syndrome