Human digestive system digestive system is subject to a wide range of disorders many of which can be congenital. Mouth diseases can also be caused by pathogenic bacteria, viruses, fungi and as a side effect of some medications. Mouth diseases include tongue diseases and salivary gland diseases. A common gum disease in the mouth is gingivitis which is caused by bacteria in plaque. The most common viral infection of the mouth is gingivostomatitis caused by herpes simplex. A common fungal infection is candidiasis commonly known as "thrush" which affects the mucous membranes of the mouth. There are a number of esophageal diseases such
Human disease modifier gene involve large human populations in which genetic modifiers cannot be experimentally manipulated. Thus, in human populations the roles of genetic modifiers are often established by statistical implications, without evidence for causation or opportunity for functional characterization. The study of human disease modifiers and oligogenic disease is a hybrid field that can yield unique and comprehensive insight into complex mechanistic causes of human disease, necessary for the development of effective therapeutics Characterizing complex multi-gene interactions responsible for disease- and further, developing effective therapeutics- is exceedingly difficult, and the molecular mechanisms of few oligogenic diseases have been elucidated. Retinitis pigmentosa is one