Agenesis of the corpus callosum with peripheral neuropathy or Andermann syndrome is an autosomal recessive disorder rarely found outside certain regions of the province of Quebec, Canada. We report a 5-year-old Turkish patient with Andermann syndrome born to consanguineous parents. She presented with diffuse hypotonic weakness, predominantly in the distal extremities, and mild mental retardation. Electromyography showed axonal-demyelinating sensorimotor neuropathy. Sural nerve biopsy was compatible with demyelinating neuropathy. Cranial magnetic resonance imaging revealed total agenesis of the corpus callosum, dilatation of the interhemispheric fissure, and enlargement of the cisterna magna. The molecular genetic analysis using microsatellite DNA markers covering the agenesis of the corpus callosum with peripheral neuropathy locus on chromosome 15q13-q15 showed that the patient is homozygous for the whole region. Our findings confirm that Andermann syndrome is a genetically homogeneous disorder.