|
Diagnosis Introduction The diagnosis of EB is based on the symptoms and specific diagnostics. In a neonate EB can be diagnosed by:
However, in certain types of EB the symptoms do not manifest themselves until later in life. The diagnosis of the type of EB is very important for the prognosis of the course of the disease and the treatment. In case of a family history with a hereditary defect, prenatal diagnostics can be carried out. By means of electron microscopic testing of the healthy and diseased skin and by determining the level of the blistering by means of antigen mapping, the type of EB can be determined. Electron microscopy Through the electron microscope a skin biopsy can be analyzed and the level of the defect in the epidermal basement membrane zone localized. Antigen mapping On the basis of the localization of certain antigens, a determinant for the level of the defect in the basement membrane, the level of the blistering, can be determined. The presence of basement membrane antigens (or adhesion molecules) is determined by `monoclonal marker analysis' of biopsies of the intact skin. These biopsies are usually taken from the inside of the upper arm. The biopsy is coloured and on the basis of the colouring the potential reduction of absence of adhesion molecules in the basement membrane is determined. Prenatal diagnosis In the case of couples with a defective family history of EB, prenatal diagnostics can be carried out. Prenatal diagnostics may be performed by using different methods. Until now the method most commonly used is that of fetal skin biopsy from the 18th week of gestation on. This procedure is not performed in the Netherlands but it is done in London. The fetal skin biopsy is taken with very fine forceps (20 gauge) with ultrasound guidance. The biopsy can be analyzed under the electron microscope. Conditions for the performance of a prenatal skin biopsy:
In one respect prenatal diagnostics makes it possible in the case of a diagnosis of EB to decide at an early stage on the future of the child and for the parents with a positive history it is reassuring to hear that their child does not suffer from EB. Chorionic villus sampling For a short time now, in all three main types of EB, prenatal diagnostics can be performed through chorionic villus biopsy (chorionic villus sampling). After the 9th - 10th week of pregnancy, tissue is taken from the placenta with a very fine forceps that is inserted through the vagina. Conditions for the performance of chorionic villus sampling are:
|
