Whereas cyclin E expression by itself decreased the average replication rate from 1.18 Kb/min in cells expressing an empty vector to 0.79 Kb/min (P < 2.4 × 10−21), folate deficiency further reduced the average replication rate to 0.59 Kb/min (P < 1 × 10−13) (Fig3A). This evidence concerns the gene CCNE1 and hyperinsulinemic hypoglycemia, familial, 4.