Variable | n | Age, Mean ± SD, y | Head Circumference, Mean ± SD, cm | Clinical Severity Scores, Mean ± SD | |||||
---|---|---|---|---|---|---|---|---|---|
Total | Head Growth | Seizures | Respiratory Irregularities | Scoliosis | Gait Abnormalities | ||||
All RTT subjects | 22 | 8.6 ± 1.8 | 49.5 ± 2.1 | 7.8 ± 2.4 | 2.5 ± 0.8 | 1.2 ± 1.0 | 1.7 ± 0.8 | 0.7 ± 1.0 | 1.6 ± 1.0 |
Affected MZ twin | 8.4 | 50.5 | 8 | 3 | 1 | 2 | 0 | 2 | |
More severe (gait criterion) | 12 | 8.8 ± 1.6 | 49.3 ± 2.4 | 9.6 ± 1.3* | 2.6 ± 0.7 | 1.4 ± 1.0 | 1.8 ± 0.8 | 1.7 ± 1.2* | 2.4 ± 0.7* |
Less severe (gait criterion) | 10 | 8.3 ± 2.1 | 49.4 ± 1.8 | 5.9 ± 1.5 | 2.5 ± 1.0 | 1.0 ± 1.1 | 1.6 ± 0.8 | 0.1 ± 0.3 | 0.7 ± 0.7 |
Control subjects | 25 | 8.9 ± 1.9 |
Note:—RTT indicates Rett syndrome; MZ, monozygotic. Age represents age at time of MR imaging scan. The maximum total clinical severity score is 15. The “more severe” group included the following mutations: R106W (n = 1), T158M (n = 3), R255X (n = 1), R270X (n = 2), R294X (n = 2), and C-terminal deletions (n = 3). The “less severe” group included the following mutations: R133C (n = 1), R168X (n = 1), R255X (n = 1), R294X (n = 4), R306C (n = 2), and G451T/D151Y (n = 1 each).
* P < .05 when comparing more severe versus less severe gait.