Hand and foot growth failure in Rett syndrome.

Growth failure is a major aspect of the developmental arrest in Rett syndrome. Small hands and feet have been reported anecdotally, but the pattern of hand and foot growth has not been studied rigorously. The aims of this study were to characterize the hand and foot growth of 28 girls with Rett syndrome and to examine the relationship between their hand or foot size and height. Median hand length deviated to the 5th percentile at 11 years of age whereas median foot length and height deviated below the 5th percentile at 5.5 years of age. After adjusting for height-age, a greater proportion of foot lengths than hand lengths was less than the 50th percentile. In conclusion, the rate of hand and foot growth of girls with Rett syndrome is slower than that of the normal female. Moreover, the rate of deceleration of foot, but not hand, growth relative to height growth is greater. Thus, many girls with Rett syndrome have "small" feet, but not hands, for their height.