title: Association of amino levulinate dehydratase levels and ferrochelatase inhibition in childhood lead exposure.
abstract: The basis for the clinical variation in response to lead exposure in children is not well understood. We studied selected children from a large lead screening program in whom elevation of red cell protoporphyrin concentration (a measure of inhibition of the enzyme ferrochelatase) was markedly above or below average for a given blood lead level. We then measured the activity of the enzyme amino levulinate dehydratase in 306 of these children, and found that ALA-d activity was lower in children with higher protoporphyrin elevation, independent of the effects of lead. This observation, coupled with reports in the literature of families with ALA-d deficiencies and elevated red cell protoporphyrin values, makes likely a genetic basis for some of the variation in susceptibility to lead. The mechanism by which the two effects are associated remains unknown.
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004198:Disease Susceptibility; D004781:Environmental Exposure; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D005294:Ferrochelatase / Q000037:antagonists & inhibitors*; D006400:Hematocrit; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood*; D007855:Lead Poisoning / Q000097:blood; D008190:Lyases / Q000037:antagonists & inhibitors*; D008297:Male; D000623:Porphobilinogen Synthase / Q000097:blood*; D011524:Protoporphyrins / Q000097:blood; D012805:Sickle Cell Trait / Q000097:blood
chemical_list: D011524:Protoporphyrins; D007854:Lead; D008190:Lyases; D000623:Porphobilinogen Synthase; D005294:Ferrochelatase