Joubert syndrome (JS) is a autosomal-recessive disorder characterized by hypotonia, ataxia, developmental delay, disordered breathing, and abnormal ocular movements. 1 The pathognomonic MRI hallmark of JS is the ''molar tooth sign'' (MTS), resulting from thickening and horizontalization of superior cerebellar peduncles and prominence of the interpeduncular fossa. 2 A 16-year-old girl was referred for episodes of subjective feeling of ''lack of air'' mainly recurring during handling or stress and diagnosed as panic attacks. Neurological examination revealed prominent chin, ogival palate, dysphonia, dysmetria, general hypotonia, severe ataxic gaitb and mild mental retardation. A check for heart defects was negative. Brain MRI showed vermian aplasia and a dilated fourth ventricle, that is, the MTS (Fig. 1A). Videopolysomnography (VPSG) gave away breathing instability to be ''ataxic'' in shape, more than periodic, and consisting in repetitive but not predictable tachypnea, followed by central apnea, recurring during wake, light NREM, and REM sleep (Fig. 1B), not associated with other signs of respiratory distress and suggesting a rostrocaudal disorganization of brain stem respiratory rhythm generator(s).
Our patient fulfilled the criteria for pure JS. 1 The pattern and timing of unusual respiratory behaviors may be an important diagnostic clue in JS, and VPSG should be mandatory whenever this condition is suspected.