Figure 1
From: Developmental delay in Rett syndrome: data from the natural history study
Inverse Kaplan-Meier graphs were created for acquired developmental milestones. Expected upper limits of normal are represented by the vertical blue line [17]. These plots represent the early four skills, (A) sitting alone, (B) reaching, (C) fixing and following, and (D) social smile. The remaining acquired skills and the Kaplan-Meyer graphs for lost skills are displayed as additional files. In each case, more than 95% (517/542) of classic RTT and more than 97% (93/96) of atypical RTT participants reported a specific age of acquisition for each skill.