Mucositis is the painful inflammation and ulceration of the mucous membranes lining the digestive tract, usually as an adverse effect of  chemotherapy and radiotherapy treatment for cancer. Mucositis can occur anywhere along the gastrointestinal (GI) tract, but oral mucositis refers to the particular inflammation and ulceration that occurs in the mouth. Oral mucositis is a common and often debilitating complication of cancer treatment.Oral and gastrointestinal (GI) mucositis affects almost all patients undergoing high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT), 80% of patients with malignancies of the head and neck receiving radiotherapy, and a wide range of patients receiving chemotherapy. Alimentary tract mucositis increases mortality and morbidity and contributes to rising health care costs.For most cancer treatment, about 5–15% of patients get mucositis. However, with 5-fluorouracil (5-FU), up to 40% get mucositis, and 10–15% get grade 3–4 oral mucositis. Irinotecan is associated with severe GI mucositis in over 20% of patients. Seventy-five to eighty percent of bone marrow transplantation recipients experience mucositis, of which oral mucositis is the most common and most debilitating, especially when melphalan is used. In grade 3 oral mucositis, the patient is unable to eat solid food, and in grade 4, the patient is unable to consume liquids as well.Radiotherapy to the head and neck or to the pelvis or abdomen is associated with Grade 3 and Grade 4 oral or GI mucositis, respectively, often exceeding 50% of patients. Among patients undergoing head and neck radiotherapy, pain and decreased oral function may persist long after the conclusion of therapy.
Pai syndrome, also known as Median cleft of the upper lip-corpus callosum lipoma-midline facial cutaneous polyps syndrome, is a very rare genetic disorder which is characterized by nervous system, cutaneous, ocular, nasal and bucal anomalies with facial dysmorphisms. Signs and symptoms
List of common symptoms:
Depressed nasal bridge
Median cleft lip
Central nervous system lipomas. Nasal polyposis
Presence of skin tags
Subcutaneous noduleList of not-so-common symptoms:[2]

Oral frenulum abnormalities
Bifid uvula
Hypertelorism
TelecanthusList of uncommon symptoms:[2]

Missing/underdeveloped corpus callosum
Down-slanting parpebral fissures
Encephalocele
Coloboma
Nose defects
Frontal bossing
High palate

Causes
A specific, shared genetic cause hasnt been found. The closest thing to it was a case reported by Masuno et al. of a Japanese girl with symptoms of the disorder plus short stature and intellectual disabilities with a spontaneous reciprocal translocation. This translocation involved chromosome Xq28 and chromosome 16q11.2 (more specifically, 46,X,t(X;16)(q28;q11.2). Epidemiology
According to OMIM, 18 cases have been described in medical literature, but according to ORPHAnet, 67 cases have been described. == References ==