Figure 1: The functions of the protein products of disease genes.

a, The entire disease gene set. b–f, Disease genes stratified according to the typical age of onset of the disease phenotype. The fraction of disease genes encoding transcription factors in the in utero onset disorders (25%) differs from the fraction encoding transcription factors for disorders with onset after birth (6%; χ² = 49.4, P < 0.001). Similarly, the fraction of disease genes encoding enzymes causing a disorder with onset in the first year of life (47%) is different from the fraction encoding enzymes causing disorders with other ages of onset (25.8%; χ² = 35.8, P < 0.001).