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 in mice, that sequence polymorphisms in Mtap1a are crucial in causing the hearing-loss phenotype associated with tub gene mutation. Unexplained variation in human disease phenotype is a complex issue, and with established methodologies of identifying and characterizing modifier genes, it is tempting to pursue them as explanation, with the potential to lead to a better understanding of the biological mechanisms of disease, such as by characterized interactions between gene products. But identifying new modifier loci is challenging, and becomes more so, as those variants most easily detectable by current methods are increasingly identified and characterized. Still, for a majority human