Rett syndrome: a retrospective pilot study on potential early predictive symptomatology.

A pilot study is presented, in which traditional neurodevelopmental parameters were retrospectively used in an attempt to compare the early development of 10 young girls with Rett syndrome (RS) to that of considered normality in child health screening. The early developmental profile at key ages was defined by applying the Denver Developmental Screening Test frames for the range of normal development, to the achievements recorded for each child during routine developmental assessment in Swedish child health care. Key ages chosen were 6, 9-10, 15, 18 and 24 months. At the 6 month level no predictive deviations could have been revealed. At 9-10 months suspicions of abnormal development could have been arisen from a delayed, dissociated motor development combined with immaturity of equilibrium functions. Developmental deviations and neurological signs indicative of RS had been present in 5 of the girls at 15 months, in 8 at 18 months and in all 10 at 24 months. Possible predictive signs were loss of acquired hand skill and learned single words, diminished communication and contact ability, appearance of truncal instability and dysequilibrium signs. The insidious appearance of motor developmental deviations during infancy, dwelling inside the concept of normality, was confirmed. Loss of acquired manipulative hand skill, often mixed with non-specific circulating hand-mouth movements, still constitutes the single most informative early warning signal for the syndrome.