[Oral manifestations of systemic diseases]. / Mundschleimhaut als Spiegel systemischer Erkrankungen.

Many systemic diseases may present with oral manifestations and the oral mucosa may act as a mirror of internal involvement. We discuss the most common, specific and unspecific, as the most peculiar oral mucosal manifestations of systemic disease in the different organ systems. The most prevalent conditions of the oral mucosa in the course of HIV infection and marker lesions of multisystemic genodermatoses are elucidated.

[Genetic counseling and DNA testing in patients with increased risks for malignant melanoma]. / Genetische Beratung und DNA-Testung für Patienten mit erhöhtem Melanomrisiko.

There are numerous risk factors for the development of malignant melanoma. It has been documented that genetic predisposition exists but exogenous factors are also very important. In familial melanomas it has been well established that mutation in the CDKN2A gene which is located at chromosome 9 leads to a marked risk for malignant melanoma. This tumor-suppressor gene is important for the regulation of the cell cycle and mutation in this gene is associated also with an increased rate of pancreas cancer. The penetrance of this mutation is influenced by UV-energy. In addition it has been shown that a second cluster for the familial atypical nevus syndrome is located at chromosome 1p36. Patients with the rare disease xeroderma pigmentosum have a defect in the DNA-repair mechanism inherited in an autosomal recessive trait and therefore develop within the first 20 years of life numerous malignant skin tumours including malignant melanomas. But also in non-syndromic patients a decrease of DNA-repair ability may occur. It has been shown recently that reduced DNA-repair ability is an independent risk factor for malignant melanoma and may contribute to susceptibility to sunlight-induced melanoma among the general population. Other constitutional risk factors for the development of malignant melanoma are fair skin, red hair and blue eyes. The most important exogenous risk factor is UV-exposition. Extensive and repetitive sunburns before the age of 15 years are especially predisposing to malignant melanoma. The most important preventive measures are continuous sun-protection including avoidance of sun in noon time on tropical and subtropical places, wearing a hut and sunglasses and application of sun-screens with high sun-protection factor. Furthermore a regular check for changing moles is indicated in persons with multiple atypical nevi or a familial melanoma syndrome. Nowadays molecular genetic screenings are available within research projects for members of melanoma-prone families. The controversy of such possibilities is discussed.

[Skin and hair, marker organs for thyroid diseases]. / Haut und Haar, Markerorgane für Schilddrüsenerkrankungen.

Skin and cutaneous appendages are target organs for thyroid hormones. Thus, a variety of changes of skin, hair and nails occurs in association with thyroid diseases. Most of these cutaneous changes are unspecific, but in their entirety they may nontheless be indicative of thyroid diseases. In this review the specific cutaneous lesions as thyroglossal duct cysts and cutaneous metastases of thyroid carcinoma, the unspecific cutaneous changes of hypo- respectively hyperthyroidism, the typical skin lesions of Grave's disease, and selected skin diseases and syndromes associated with thyroid abnormalities are discussed.