Since it is now known that the frequency of GATA1 mutations at birth is much higher than previously realised (25–30 % of all neonates with Down syndrome) and since population-based estimates of the frequency of ML-DS indicate that ∼1.5 % of children with Down syndrome will develop this leukaemia before the age of 5 years [1], this suggests that the risk of progression is lower than these original estimates (around 5–10 %) given that silent TAM also has the potential to transform to ML-DS. The gene discussed is GATA1; the disease is Down syndrome.