Alterations of catecholamine enzymes in several brain regions of victims of sudden infant death syndrome.

Dopamine-beta-Hydroxylase (DBH) activity is decreased and tyrosine hydroxylase activity is increased in three brain regions (hypothalamus, putamen, and caudate nucleus) from victims of Sudden Infant Death Syndrome (SIDS) when compared to values in the same regions from infants dying of known causes. No stastically significant difference was detected in tyrosine hydroxylase activity in the thalamus and brain stem although DBH was 20% lower in the former region of the SIDS victims. Two other enzymes of biogenic amine metabolism, catechol-o-methyl transferase and Dopa-decarboxylase, were essentially the same in both groups. These data are consistent with the hypothesis that an alteration in the central nervous system may be a factor in the pathophysiology of SIDS.