There are several types of HSAN, classified based on the specific genetic mutations and the symptoms they cause. The most common types include:
- HSAN Type I: Usually presents in adolescence or adulthood, rarely affecting neonates. - HSAN Type II: Manifests early, often in infancy or childhood, and is characterized by a loss of pain and temperature sensation. - HSAN Type III (Riley-Day Syndrome): Often presents in neonates with symptoms like poor muscle tone, feeding difficulties, and autonomic dysfunction. - HSAN Type IV: Known as Congenital Insensitivity to Pain with Anhidrosis (CIPA), it presents in neonates with an inability to feel pain and temperature, and an inability to sweat.
