Myogenic tremor - a novel tremor entity.

PURPOSE OF REVIEW: Tremor is a common neurological symptom with a plethora of potential etiologies. Apart from physiological tremor, the vast majority of tremor syndromes are linked to a pacemaker in the central nervous system (CNS) or, less common, in the peripheral nervous system. Myogenic tremor is a novel tremor entity, first reported in 2019 and believed to originate in the muscle itself. In this review, we describe the clinical properties of myogenic tremor and discuss its presumed pathogenesis on the basis of all of the patient cases published so far.

RECENT FINDINGS: Myogenic tremor manifests itself as a high frequency, postural, and kinetic tremor with onset in infancy. To date, only myopathies affecting the contractile elements, in particular myosin and a myosin-associated protein, have been recognized to feature myogenic tremor. The generator of the tremor is believed to be located in the sarcomere, with propagation and amplification of sarcomeric oscillatory activity through CNS reflex loops, similar to neuropathic tremor.

SUMMARY: True myogenic tremor must be distinguished from centrally mediated tremor due to myopathies with central nervous system involvement, i.e., mitochondrial myopathies or myotonic dystrophies. The presence of myogenic tremor strongly points toward a sarcomere-associated mutation and may thus be a valuable clinical tool for the differential diagnosis of myopathies.