Autosomal dominant spinocerebellar degeneration. Appears in early childhood and progresses slowly. Considered severe variant of Charcot-Marie-Tooth 1B disease.
Roussy-Levy Hereditary Areflexic Dystasia; Lévy-Roussy Syndrome; Symonds-Shaw Syndrome; Abortive type of Friedreich Disease; Familial Claw-Foot with Absent Tendon Jerks; Hereditary Areflexic Dystasia; Hereditary Ataxia-Muscular Atrophy Syndrome.
Charcot-Marie-Tooth disease is described in up to 1:2,500 overall making it the most common inherited neurological disease.
Spinocerebellar degeneration can be caused by heterozygous mutation in the peripheral myelin protein-22 (PMP22) gene or the myelin protein zero (MPZ) gene on chromosome 17p12 and 1q22.3, respectively. The latter protein is one of the major structural proteins of the peripheral nervous system. A demyelinating and a more commonly a hypertrophic (onion-bulb) form is described.
Association of truncal ataxia, lower limb muscular atrophy, bilateral pes cavus, and loss of deep reflexes. Conduction velocities are below 38 m/s.
Symptoms first appear in early childhood and progress slowly throughout life with moderate disability. Beyond ataxia, loss of reflexes, and muscular atrophy, clinical features can include scoliosis, absent leg tendon jerks, distal sensory loss, static hand tremor, abnormal gait, and slow peripheral nerve conduction velocity. Absence of cerebellar signs, speech disturbances, Babinski sign, and nystagmus.
Precautions before anesthesia
Evaluate muscular weakness (clinical) and neurological function (clinical, EMG, somatosensory evoked potentials, nervous conduction speed). Patients have frequent osteoarthritic and muscular pain.
Careful intraoperative monitoring. Regional anesthesia is not contraindicated; complete information about the risks involved has to be clearly expressed by the physician and understood by the patient/parents. However, there is no impact on the progression of the disease. Similar to most cases of Friedreich Ataxia, somatosensory evoked potential intraoperative monitoring during scoliosis surgery should be impossible. Slow peripheral nerve conduction velocities make monitoring of neuromuscular difficult to interpret. Use of the facial nerve instead is recommended.
Avoid succinylcholine because of the risk of hyperkalemia as a consequence of muscle denervation. However, there is no risk of malignant hyperthermia.
Other conditions to be considered
☞Friedreich Ataxia (FRDA): Genetic disorder characterized by a progressive dysfunction of the posterior spinal cord, the cerebellum (ataxia, nystagmus), and peripheral nerves. It typically becomes apparent by adolescence. Clinical features include unsteady posture, frequent falling, progressive ataxia characterized by foot deformities, increasing incoordination of the arms and hands, dysarthria, and nystagmus. It may also be associated with cardiomyopathy, chest pain, arrhythmias, and diabetes mellitus. All patients have normal intelligence.
☞Charcot-Marie-Tooth Disease: Hereditary polyneuropathy condition presenting with distal weakness and muscular atrophy or myopathy. ...