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 therapies that are individually effective. Characterization of these phenotypes and the genes responsible for them, has relied on a combination of molecular techniques typically used to characterizing simple, monogenic disease, and statistical methods, typically used to characterize complex traits. Understanding the mechanism of disease modifier genes and oligogenic inheritance may provide unique insights into the functions of gene-gene interactions that underlie human disease. Currently, techniques for molecular characterization of disease mechanisms are established for many monogenic diseases, but these studies do not improve understanding of genetic interactions and their phenotypic implications. Methodology for studying complex traits are primarily statistical, and