1 Medical College of Virginia, Department of Pediatrics, Richmond, Virginia 23219
The study by Blackburn and associates, showing the lack of additive effect of phenobarbital when used in combination with phototherapy in lowering the serum bilirubin concentration in one identical twin in each of six sets, eliminates the possible interference of genetic background on bilirubin metabolism. As part of a larger study, we have previously presented and reported similar results in a controlled study of 75 low birth weight infants of a predominantly Negro population. Members of each of our therapy groups (phenobarbital, light, phenobarbital and light, no therapy) were comparable with respect to birth weights and initial serum bilirubin concentrations, and were kept in similar environments, although their genetic backgrounds were dissimilar.