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In contrast to several authors who found hepatic cytochrome P 450 2D6 (CYP2D6) metabolising status to be clinically unimportant in treatment with the CYP2D6 substrate, risperidone, we report on a 17-year-old schizophrenic patient who suffered from severe extrapyramidal side effects (EPS) while being treated with risperidone at 4 mg per day. He was genotyped as a CYP2D6 poor metaboliser (PM). The active moiety of risperidone (sum of risperidone and 9-hydroxyrisperidone) was elevated and increased even further under co-medication with haloperidol and biperiden. We conclude that the PM phenotype for CYP2D6 of this patient had major clinical importance in treatment with risperidone. Most likely metabolic pathways other than CYP2D6 were also involved that are probably inhibited by haloperidol.

alpha-Thalassaemia is a disturbance of the alpha-chain synthesis of the haemoglobin, which occurs mostly in the Far East. On account of the total absence of alpha-chains, the homozygous form is considered to be fatal. However, beta and lambda chains exist abundantly. Abortion, intrauterine or perinatal death are the results of the extreme anaemia (Hb-Bart's syndrome), despite modern intensive medical care. The prenatal diagnosis is possible by: 1. DNA analysis of material obtained by chorion villi sampling or culture of fibroblasts, when a risk of re-occurrence is known to the physician. 2. Hb-electrophoresis from foetal blood in cases of hydrops of uncertain origin. When the diagnosis of this fatal disease is established, there is no foetal indication for delivery by Caesarian section.

After an extensive educational campaign for the medical community in the area of the Westf. Wilhelms-University Münster five pregnancies at risk for sickle cell anemia and thalassemias were investigated during the first trimester of pregnancy. Following chorionic villi sampling in one case a sickle cell anemia and in two other cases a beta-thalassemia could be excluded. In two additional cases a homozygous beta-thalassemia was proven and in one of the cases the first trimester diagnosis was confirmed in the second trimester by fetal blood sampling. Because of the migration patterns in Europe there is currently a considerable demand for prenatal diagnosis of beta-thalassemias in West-Germany after proper information of the population at risk.