A very rare genetic disorder characterized by
predominant neurological syndrome with alteration of cerebellum and globus
pallidus. Muscular functions can also be affected.
Myoclonus and Ataxia Syndrome.
Autosomal dominant, heterogeneous.
Neurological lesions or anomalies are often
observed (cerebellar dentate nucleus, degeneration of globus pallidus,
elevated cerebrospinal fluid uric acid); muscle biopsy shows the presence of
ragged red fibers that probably are caused by mitochondrial abnormalities,
which could explain the pathophysiology of this syndrome. Controversy exists
about considering Ramsay Hunt Syndrome as a specific entity.
Association of myoclonus ataxia and occasional seizures.
Neurological signs are isolated. No other
association is known. Myoclonus, cerebellar ataxia, intention tremor, and
occasional tonic-clonic seizures are the only symptoms.
Evaluate the neurological
repercussion. Evaluate muscular status especially for the presence of myoclonic tone.
Verify ability of patients to use patient-controlled analgesia if necessary.
The presence of epilepsy must be considered and
medication known to stimulate convulsions (e.g., sevoflurane) should be avoided.
The antiepileptic medication must be continued
until the morning of surgery. Avoid succinylcholine in presence of muscular abnormalities and
potential risk (undocumented) of hyperkalemic response. Avoid enflurane, methohexital, and
hypnomidate because of seizure.
Juvenile Paralysis Agitans of Hunt: Autosomal dominant. This syndrome is characterized by mask-like facies,
parkinsonism, tremor, bradykinesia, dysarthria, rigidity, gait disturbance,
and flexion dystonia of fingers. Progression is slow. Onset in teens or
Dyssynergia Cerebellaris Myoclonica of Hunt (Cerebelloparenchymal Disorder V, Spinodentate Atrophy):
Autosomal recessive with ataxia, myoclonic jerks, dentate neuron loss superior, and
cerebellar peduncle fiber loss.
Bomont P, Watanabe M, Gershoni-Barush R, et al: Homozygosity mapping of
spinocerebellar ataxia with cerebellar atrophy and peripheral neuropathy to
9q33-34, and with hearing impairment and optic atrophy to 6p21-23. Eur J Hum Genet