The paralytic tremor (pt) disease in rabbits results from a point mutation in a plp gene and manifests itself by a broad range of neurological signs. Biochemical studies have shown that myelinogenesis is retarded and deficient in mutant rabbits. Myelin sheaths are usually thin and malformed. The number of oligodendrocytes is normal, however their differentiation and maturation is prolonged. The effects of the pt mutation were investigated in morphological, biochemical and molecular studies, resulting in the well-documented characteristics of the disease. The pt phenotype and its detailed characteristics make the mutated rabbit a good model of Pelizaeus-Merzbacher disease.