RESEARCH which goes to the core of the problem directly and with finesse can elicit admiration. The investigation reported in this issue by Dancis and colleagues will find a number of readers experiencing such appreciation.
Hypervalinemia has been reported in only one infant in the world, but rarity is not the reason for its interest; this "experiment of nature," discovered as if by accident, has been a most informative disease. Working with as little as 2 ml of blood taken from the patient, Dancis and colleagues studied the metabolism of valine in the white cells in the sample. The simplicity of the "biopsy" and the elegance of the isotope methods are most exemplary.