Apolipoprotein A-I:B ratio and B screening: a preliminary study of 10- and 11-year-old children.

The apolipoprotein (apo) A-I:B ratio and the apo B concentration were determined by radial immunodiffusion in dried blood spot samples from 1,767 10- and 11-year-old children. Children with either apo A-I:B ratios below the first percentile or apo B levels above the 99th were recalled and plasma lipid and apolipoprotein profiles were determined for both children and parents. Of 17 children (one family was lost to follow-up) recalled due to abnormal apo A-I:B ratios, apo B levels were above the 95th percentile in 13 children, and of 18 children with abnormal apo B screening levels (three of them also had abnormal apo A-I:B ratios), the plasma apo B level was elevated in 13 children. The 23 children with abnormal blood lipid and/or apolipoprotein concentrations were divided into two main groups: (a) children with type IIa hyperlipoproteinemia and (b) children with hyperapo B lipoproteinemia (hyperapo B) and normal blood lipid levels. Twelve children had the type IIa pattern. Five children likely had familial hypercholesterolemia (FH), the other seven children may have hypercholesterolemia due to obesity or environmental factors. Eleven children had the hyperapo B abnormality. In four children, the elevated apo B level probably was an indication of the occurrence of familial combined hypercholesterolemia (FCH) in the family. Of the remaining seven hyperapo B children, three children also had a parent with hyperapo B and a fourth family suffered from obesity.(ABSTRACT TRUNCATED AT 250 WORDS)