Table 1.
Prominent signs and peculiarities in infants later diagnosed with typical Rett syndrome
| Rate of occurrence | References | |
|---|---|---|
| Poor repertoire general movements (birth–2 months after term) | 9/11 (82 %) | [7, 18, 20, 21] |
| Absent or abnormal fidgety movements (3–5 months after term) | 14/14 (100 %) | [7, 18, 20, 21] |
| Significant delayed in or no achievement of sitting alone, pulling to stand or walking alone | 20–50 % | [20, 25, 27, 28] |
| Touching objects with extended fingers rather than manipulating them | 14/24 (58 %) | [7, 20, 30] |
| Hand stereotypies | >50 % | [7, 19, 20, 29–32] |
| Asymmetric opening of the eye lid after a blink | 10/18 (56 %) | [7] |
| Frozen, bizarre, inadequate smile | >35 % | [6, 7, 20, 26] |
| Repetitive or long-lasting tongue protrusion | 13/21 (62 %) | [7, 20, 29] |
| Delay and/or abnormalitiesa in cooing vocalisation and canonical babbling | >50 % | [8, 20, 33, 34, 37] |
| Limited use of gestures | 13/16 (80 %) | [11, 20, 26, 38, 39] |
| Delay in speaking the first (proto-)word | >80 % | [8, 20, 34, 39] |
| Insensitivity to pain | Anecdotic | [20, 26, 27, 30] |
aProto-vowel or proto-consonant alternations produced on ingressive airstream, breathy voice characteristics and pressed or high-pitched vocalisations.