We report on two siblings, a boy and a girl, with agenesis of corpus callosum and
neuronopathy. The children show diffuse hypotonia, delayed motor and mental development.
Neurophysiological examinations revealed reduction of the motor nerve conduction velocity,
absence of sensory nerve action potentials, abnormal somatosensory and visual evoked
potentials. Nerve biopsies showed reduced density of myelinated and unmyelinated fibres
in both children. We also found signs of hypomyelination and suggest this is secondary
to degeneration of peripheral sensory and motor neurons. Our findings are consistent
with the diagnosis of Andermann syndrome. This is the first report of the occurrence
of Andermann syndrome out of French Canada.
Andermann syndrome - Agenesis of corpus callosum - Hereditary neuronopathy
