Hereditary Conditions, Genetics, and Mutations
Inherited abnormalities in the genetic material passed down from parent to child are among the many causes of peripheral neuropathy. Sometimes, when there are no hereditary conditions, single or multiple mutations in the genes expressed by neurons and Schwann cells may cause motor, sensory, autonomic, and peripheral neuropathy phenotypes.
Typically, hereditary peripheral neuropathy (HPN) is categorized into three different types—autosomal dominant or recessive X-linked (CMT1), axonal (Wallerian) degeneration and autosomal dominant pathogenic mutations (CMT2), and rare autosomal dominant or recessive disorder with mutations in several genes (CMT3). All types exhibit symptoms early and develop as the affected individual matures. On the other hand, some less common types show signs at birth resulting in worse disability. These types appear in different diseases, including Charcot-Marie-Tooth disease (CMT) or peroneal muscular atrophy, and Dejerine-Sottas disease.
HPN symptoms differ per subtype, but some exhibits loss of motor and sensory neurons. Other symptoms include enlarged peripheral nerves and onion bulbs, distal pain and temperature insensitivity, and loss of vibratory and position sense. It results in a high risk of infections, osteomyelitis, and other physiologic abnormalities.
