Variegate porphyria, also known by several other names, is an autosomal dominant porphyria that can have acute (severe but usually not long-lasting) symptoms along with symptoms that affect the skin. The disorder results from low levels of the enzyme responsible for the seventh step in heme production. Heme is a vital molecule for all of the bodys organs. It is a component of hemoglobin, the molecule that carries oxygen in the blood. Signs and symptoms
When symptoms occur, they can include acute attacks (similar to acute intermittent porphyria) or skin damage. Acute attacks usually begin in adulthood and cause abdominal pain, vomiting, diarrhoea and constipation. During an attack, a person may also experience muscle weakness, seizures, and mental changes such as anxiety and hallucinations. These signs and symptoms are triggered by nongenetic factors such as certain drugs, dieting or fasting, certain hormones and stress.Some people with variegate porphyria have skin that is overly sensitive to sunlight (photosensitive). Areas of skin exposed to the sun develop severe blistering, scarring, changes in pigmentation, and increased hair growth. Exposed skin becomes fragile and is easily damaged.Rarely, the signs and symptoms of variegate porphyria can begin in infancy or early childhood. In such cases, the signs and symptoms are usually more severe than those starting later in life. Genetics
Mutations in the PPOX gene cause variegate porphyria. The PPOX gene makes a membrane bound mitochondrial enzyme called protoporphyrinogen oxidase, which is critical to the chemical process that leads to heme production.
Diagnosis
Classification
The World Health Organization (WHO) has identified three subtypes of nasopharyngeal carcinoma:
type 1: squamous cell carcinoma, typically found in older adults
type 2: non-keratinizing carcinoma
type 3: undifferentiated carcinomaType 3 is most commonly found among younger children and adolescents, with a few type 2 cases. Both type 2 and 3 have been found to be associated with elevated levels of Epstein-Barr virus titers, but not type 1. Additionally, type 2 and type 3 may be followed with an influx of inflammatory cells, including lymphocytes, plasma cells, and eosinophils, generating the term lymphoepithelioma.Nasopharyngeal carcinoma, also known as nasopharyngeal cancer, is classified as a malignant neoplasm, or cancer, arising from the mucosal epithelium of the nasopharynx, most often within the lateral nasopharyngeal recess or fossa of Rosenmüller (a recess behind the entrance of the eustachian tube opening). The World Health Organization classifies nasopharyngeal carcinoma in three types, in order of frequency: Non-keratinizing squamous cell carcinoma; keratinizing squamous cell carcinoma; and basaloid squamous cell carcinoma. The tumor must show evidence of squamous differentiation, with the non-keratinizing type (also known as lymphoepithelioma) the tumor most strongly associated with Epstein–Barr virus infection of the cancerous cells. Staging
Staging of nasopharyngeal carcinoma is based on clinical and radiologic examination. Most patients present with Stage III or IV disease. Stage I is a small tumor confined to nasopharynx. Stage II is a tumor extending in the local area, or that with any evidence of limited neck (nodal) disease. Stage III is a large tumor with or without neck disease, or a tumor with bilateral neck disease.