Sulfatide antibody syndrome (idiopathic sensory polyneuropathy). Sulfatide is a glycolipid found in greatest quantity in CNS and peripheral nerve myelin. Some patients develop antibodies against sulfatide, leading to destruction of peripheral nerve axon myelin sheaths. These changes are greater in sensory nerves than motor nerves, producing paresthesias with symptoms of numbness and burning as well as impairment of touch and temperature perception. An ELISA-method test has been described to detect antisulfatide antibodies. Only high titers are considered diagnostic. The test is available only in a few large reference laboratories and university medical centers. Besides idiopathic sensory polyneuropathy, elevated titers of antibody against sulfatide have also been reported in about 85% of patients with idiopathic chronic inflammatory demyelinating polyradiculoneuropathy and 19%-65% of patients with the Gullain-Barrй syndrome.

Familial amyloidotic polyneuropathy (FAP). This is the most common form of hereditary amyloidosis. Familial amyloidotic polyneuropathy (FAP) comprises about one third of cases involving small fiber neuropathy. Amyloid is deposited in autonomic system ganglia and peripheral nerve fibers, both myelinated and nonmyelinated. Symptoms usually begin in the third and fourth age decade. About 50% of cases begin with sensory impairment that begins in the legs and eventually involves the arms, hands, and body trunk in a symmetrical distribution. After sensory loss begins, motor loss may follow some time later. In about 40% of cases, autonomic nervous system symptoms predominate, with diarrhea, constipation, vomiting, loss of sphincter control, and impotence. FAP is also associated with a genetic abnormality in one of the plasma proteins called transthyretin (TTR). Detection of the abnormal transthyretin molecule is useful as an indirect test for the presence of FAP. TTR is currently detected by nucleic acid probe with PCR amplification.

Other syndromes. Both Hu antibody syndrome (previously described) and IgM (MAG) antibody syndrome (previously described) are predominantly motor nerve dysfunction syndromes that can have a sensory component.