Hereditary sensory and autonomic neuropathy type V (
HSAN V) is an autosomal recessive disorder characterized by the loss of deep pain perception. The anomalous
pain and temperature sensations are due to the absence of nociceptive sensory innervation. The
neurotrophin nerve growth factor (
NGF), by binding to
tropomyosin receptor A (TrkA) and p75NTR receptors, is essential for the development and survival of sensory neurons, and for pain perception during adulthood. Recently a homozygous missense mutation (R100W) in the
NGF gene has been identified in
HSAN V patients. Interestingly, alterations in
NGF signalling, due to mutations in the
NGF TRKA gene, have also been involved in another
congenital insensitivity to pain,
HSAN IV, characterized not only by absence of reaction to painful stimuli, but also
anhidrosis and
mental retardation. These symptoms are absent in
HSAN V patients. Unravelling the mechanisms that underlie the differences between
HSAN IV and V could assist in better understanding
NGF biology. This review highlights the recent key findings in the understanding of
HSAN V, including insights into the molecular mechanisms of the disease, derived from genetic studies of patients with this disorder.