Among all of the inherited diseases, hypertrophic neuropathy has been exclusively associated with Tibetan Mastiffs. The condition is defined as a degenerative disease that causes “severe reduction in nerve conduction velocities, infrequent denervation potential, and inconstant elevation in CSF protein”. It affects puppies in litters that have been weaning for a few weeks, with symptoms that include general weakness, muscle hypotonia, and hyporeflexia. A type of cell called Schwann cell showed signs of aberrant formations in the insulation layer that it forms around the axon of a neuron, which indicated another element had to be present for myelin degradation. There is no known treatment, but research on peripheral nerve grafts has shown that there was more to CIHN than Schwann cell defects.