Rett syndrome affects young girls. The molecular basis is mysterious. One tenable hypothesis can be that the programmed early infantile death of neuronal cells is reprogrammed. The bcl-2 gene on chromosome 22 has been shown to play a role in the apoptosis process. No sequence abnormalities were detected in the bcl-2 gene of 6 patients with Rett syndrome which could explain the pathophysiology of Rett syndrome.