Synonyms:
Hereditary sensory neuropathy HSN or Hereditary sensory autonomic polyneuropathy HSAN
Diagnosis:
Clinical +genetic testing
Clinical features:
All have sensory neuropathy without motor features
HSN1 a.k.a. Denny-Brown neuropathy:
Clinical features:
- Loss of pain and temperature sensation, ulceration of feet and hands, Charcot joints. No autonomic features
Findings on investigations:
NCS/EMG: axonal
HSN2 a.k.a. congenital sensory neuropathy, formerly Morvan’s disease:
Clinical features:
Onset in infancy
HSN3, a.k.a. Familial dysautonomia a.k.a. Riley-Day syndrome:
Autosomal recessive, IKBKAP gene chromosome 9
Clinical features:
- Absent fungiform papillae of the tongue (smooth tongue)
- Absent reflexes
- Alacrima, Hypersensitivity of pupils to parasympathomimetics, dry mouth, absent skin response to scratch and histamine injection, orthostatic hypotension
Sural nerve biopsy:
Markedly diminished number of unmyelinated and small-diameter myelinated axons
HSN4 a.k.a. congenital sensory neuropathy with loss of sweating:
Autosomal recessive
Clinical features:
Infants. Fever, loss of pain sensation