PbB and ALAD in mentally retarded and normal children.

Blood lead (PbB) and erythrocyte delta-aminolevulinic acid dehydratase (ALAD) were measured in a group (A) of 50 mentally retarded children of unknown etiology (24 boys and 26 girls; average age 13.38 years, range 10-17 years) from an institution for handicapped children in Zagreb, and in a group (B) of 50 "normal" children (31 boys and 19 girls; average age 13.36 years, range 10-17 years) from a nearby orphanage in the same area (less polluted) of northern Zagreb. The children in group A had spent an average of 4.12 years (0.6-12 years) in the institution, and came from both urban (n = 23) and rural (n = 27) areas. The children in group B had spent an average of 4.88 years (1-14 years) in the orphanage, and also came from both urban (n = 38) and rural (n = 12) areas. The data obtained indicate a very close distribution of ALAD PbB levels in both groups, but a considerably different distribution of levels in favour of a lower activity in mentally retarded children. However, PbB and ALAD in both groups were within the range of currently acceptable "normal" values. The median and range values in groups A and B, respectively, were: 132 micrograms/l (85-256 micrograms/l) and 135 micrograms/l (78-215 micrograms/l) for PbB; 49.2 European units) (27.0-65.0 European units) and 54.6 European units (27.0-69.9 European units) for ALAD.(ABSTRACT TRUNCATED AT 250 WORDS)