Familial syndrome characterized by agenesis of the
corpus callosum, mental retardation, and progressive sensorimotor
Originally described in French Canadians from Charlevoix
County, Quebec, Canada. Traced back to a couple married in Quebec City in
the 17th century. The incidence in the Saguenay and Lac St.-Jean region in the
province of Quebec has been estimated as 1:2100 live births. The carrier
rate is 1:23 inhabitants.
Autosomal recessive. The gene defect has been
mapped to 15q13-q15.
Electromyography shows absence of sensory action
potentials, slight reduction in motor nerve conduction velocity, and signs
of denervation and reinnervation in the distal muscles of the lower
extremities. Muscle biopsy shows angular fibers and atrophy. Overall
pathologic picture is suggestive of a chronic demyelinating neuropathy.
Characteristic features include brachycephaly with a
long, triangular, asymmetrical facies with hypoplastic maxilla, large
mandibular angle, high arched palate, protruding tongue, and prominent chin
with a long lip to chin distance. Bilateral blepharoptosis, hypertelorism,
nystagmus, mild ophthalmoplegia, and abnormal visual evoked potentials have
been described. The clinical course provides valuable clues to the
diagnosis. CT scans show total or partial agenesis of the corpus callosum.
Unremarkable neonatal period followed by
hypotonia and slowing of motor development, starting at age 4 to 6 months.
Although some patients can walk, by age 10 to 13 years they are
wheelchair-bound or bed-bound. Areflexia, paraparesis, psychosis, and
seizures are observed. Other features include diffuse hypotonia, absence of
deep tendon reflexes, flexion contractures in the metacarpophalangeal
joints, low-set thumbs, pes equinovarus, hammertoe deformity, syndactyly of
the toes, and sensory neuropathy in a glove and stocking distribution.
Progressive scoliosis becomes apparent with older age and may lead to
severely restrictive lung function. Moderate mental retardation with an IQ
ranging from 45 to 60 in the majority of cases.
Evaluate pulmonary function
(clinical, chest radiographs, CT, pulmonary function test, arterial blood
gas analysis). Echocardiography should be performed if cor pulmonale and
pulmonary hypertension are suspected. Assess the airway for difficult airway
management. Evaluate neurologic function (clinical, full history,
electroencephalogram, CT, MRI). Postoperative ventilatory support may be
necessary and should be arranged beforehand.
No literature is available.
Potentially difficult airway management in view of facial abnormalities.
Spontaneous ventilation should be maintained until the airway is secured.
Patients may not tolerate general anesthesia if respiratory function is
Because of increased sensitivity to
muscle relaxants, avoid depolarizing muscle relaxants and use
nondepolarizing agents cautiously under the control of a peripheral nerve
stimulator. Consider interaction between anesthetic drugs and antiepileptic
Numerous syndromes are
associated with agenesis of the corpus callosum. The following list is not
Aicardi Syndrome: Combination of myoclonic seizures with
characteristic EEG pattern, lacunar chorioretinopathy, and (complete or
partial) agenesis of the corpus callosum is characteristic of this X-linked
dominant inherited syndrome.