SNP Shot: Genomic Insights

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV, is characterized by two primary features: a loss of pain and temperature sensation, and reduced or absent sweating (anhidrosis). Symptoms typically manifest at birth or in early infancy, and with proper medical management, individuals with CIPA can survive into adulthood.

The inability to perceive pain and temperature frequently results in recurring and serious injuries. Self-inflicted injuries are prevalent among individuals with CIPA, commonly involving biting the tongue, lips, or fingers, potentially leading to auto-amputation. Furthermore, skin and bone injuries heal slowly in these individuals. Repeated trauma can result in chronic bone infections (osteomyelitis) or Charcot joints, a condition characterized by the destruction of bones and tissues surrounding the joints.

Sweating is essential for regulating body temperature. However, anhidrosis in individuals with CIPA can cause recurrent and dangerously high fevers (hyperpyrexia) and temperature-induced seizures (febrile seizures).

Beyond these key features, CIPA can present with additional signs and symptoms. Many affected individuals develop thickened, leathery skin (lichenification) on their palms and/or have deformed fingernails or toenails. They may also exhibit areas of hair loss on the scalp (hypotrichosis). Approximately half of those with CIPA show signs of hyperactivity or emotional lability, and intellectual disability is common. Some experience weak muscle tone (hypotonia) in early childhood, which typically improves with age.

Inheritance:

CIPA follows an autosomal recessive inheritance pattern. This means that both copies of the responsible gene in each cell must carry a mutation for the condition to develop. Individuals with an autosomal recessive condition inherit one mutated gene copy from each parent, who are typically carriers and do not exhibit symptoms themselves.