Congenital insensitivity to pain and anhidrosis with selective loss of unmyelinated fiber (Hereditory sensory autonomic neuropathy IV)

ABSTRACT

Hereditory Sensory Autonomic Neuropathy(HSAN) is variable rare disorder. So the classification of HSAN could be somewhat unsettled. There are intermingled overlap variants of HSAN in view of clinical manifestations and pathologic findings. Five types of HSAN have been described by Dyck(1993). Type I is dominantly inherited and affects both myelinated(MFs) and unmyetinated fibers(Ufs). Type II is recessively inherited and nerve biopsies show total absence of MFs but presence of Ufs. Type III is a recessive inherited dysautonomia. Type IV is characterized by insensitive to pain anhidrosis, and mild mental retardation with virtually absence of Ufs. Type V affects small MFs. We report a 5 year-old girl who presented with congenital insensitivity to pain, anhidrosis with mild mental retardation. In sural nerve biopsy, Ufs were virtually absent by electron microscopy. We reconfirmed previous pathologic findings in sural nerve of HSAN IV.