Reader response: IgLON5-mediated neurodegeneration is a differential diagnosis of CNS Whipple disease

Abstract

We read with interest the case report by Morales-Briceño et al.1 of IgLON5 with cranial myorhythmia. We just completed a systematic review of movement disorders in Whipple disease (WhD) that might provide useful perspective.2 The clinical picture shown here was generally consistent with WhD and even stimulus-sensitive truncal myoclonus was once reported in WhD (our second case). However, the presence of palatal tremor (PT) is unusual for this condition.2 We found only 2 cases of palatal involvement of the myorhythmia.3,4 The authors of case 2 emphasized that the absence of typical PT should encourage a suspicion of WhD.4 Schwartz et al.5 highlighted the fact that the neuropathologic hallmark of PT, olivary pseudohypertrophy, was not found in their second patient, and Van Bogaert et al.2 repeatedly emphasized the absence of palatal involvement of the myorhythmia. Another clue to an alternative diagnosis is that all 6 WhD cases with isolated cranial myorhythmia had a concomitant vertical supranuclear gaze palsy not evident in the present case. Thus, although we agree that WhD was a reasonable consideration in the reported patient, there were clinical features that favored an alternative diagnosis, as the authors eventually discovered.