The epidemiology of progressive encephalopathies in childhood. I. Live birth prevalence in west Sweden.

Progressive encephalopathies in the west Swedish region were investigated in a population-based study. Cases were allocated to one of five main groups: 1) disorders covered by impairments in subcellular organelles, 2) disorders covered by deficiencies in the intermediate metabolism, 3) biochemically undefined neurometabolic disorders, 4) neuroimmunological disorders and 5) a symptom-orientated miscellaneous group. Progressive encephalopathies were identified in 76 of 132,138 children born alive in the study area during the 16-year-period 1970-85. This gives a live birth prevalence of 0.58 per 1000. In Sweden the size of the group corresponds to that of neural tube defects and that of congenital hydrocephalus. However, a vast number of different disorders are represented.