Treatment of Rett Syndrome With rhIGF-1 (Mecasermin [rDNA]Injection)

There are two treatment periods in the trial. The multiple ascending dose (MAD) period is an intensive 4-week pharmacokinetic study which will require 3 inpatient stays and 4 half-day outpatient visits. During in-patient sessions, an IV line will be placed for frequent blood samples. A lumbar puncture will be performed by a physician at the beginning and again at the end of the MAD. The primary goal of the MAD is to determine the safety of IGF-1 therapy for girls with RTT. As such, the investigators will ask that you monitor your child's blood sugar levels using a glucometer. At the end of the MAD, you will have the option of enrolling your daughter in an additional 20 weeks of open-label IGF-1 treatment.