Menkes disease is an X-linked recessive disease with an unknown disturbance in the copper-metabolism. We have been diagnosing patients for the last 15 years. Until 1978, six Danish families with Menkes disease were detected. Since 1978 we have only diagnosed one additional patient and one affected fetus in one of the already known families. As the incidence should be about 1 in 45,000 liveborn males, three additional patients should have been seen since 1978. To increase the chances of diagnosing all Danish Menkes patients the clinical symptoms are described. Until now, we have diagnosed 115 Menkes patients and have been in contact with more than 209 Menkes families from many different countries. If we compare the number of inhabitants per Menkes family in different countries, we obtain the following figures, 0.86 x 10(6) inhabitants per Menkes family in Denmark, increasing to 5.21 x 10(6) inhabitants per Menkes family in Italy. Finally some recent experience with copper therapy for treatment of Menkes patients is described.