Figure 1.

Fetal, infantile and pathological ballerina posturing dystonia. Ballerina posture in 35-week gestation fetus with absent corpus callosum and subsequently normal development (A), healthy 6-month old infant (B), and a 7-year old girl with typical-onset isolated monogenic dystonia secondary to the DYT-1 mutation for the past 11 months (C). The dystonia began in the left leg, spread to the right leg enforcing wheel-chair mobility after 6 months then spread to the arms: note shoulders hunched, arms extended to write, and left leg extension under the table with “ballerina” right leg posturing associated with equinovarus posturing at the right ankle. These pictures illustrate that “ballerina posturing” is common in infancy but pathological after the first year of life. The dystonia posturing may be considered a release of formerly dominant movements and postures of the legs before independent floor locomotion, standing, and walking. It is noteworthy that the ballerina posturing of the right leg was abolished as soon as the 7-year old girl regained independent standing 1 month after DBS. This reinforces the link between dystonic postures and functional levels. In this case, a transient regression to infantile posturing is brought about by dystonia.