Congenital insensitivity to pain with anhidrosis (CIPA) is one of several ectodermal dysplasias, disorders that affect the outer layer of a developing embryo. This layer, called the ectoderm, develops into body parts such as the eyes, nails, hair, and skin, including pain receptors and sweat glands.
In CIPA, the nerves that sense heat and pain are abnormal or absent. As a result, those who suffer from CIPA are insensitive to heat and pain. People with CIPA are also unable to sweat, a condition called anhidrosis, which affects the ability to regulate body temperature and may lead to fevers in hot weather.
Because people with CIPA do not sense pain, they often injure themselves. Self-mutilating behavior is also common among CIPA patients, who may bite their own tongues, lips, and fingers. Numerous injuries can result in excessive scarring, infection, and deformities. Damaged limbs may even lose function or have to be amputated.
CIPA is caused by a mutation or defect in the NTRK1 gene. It is inherited, or passed down in families, as an autosomal recessive trait. A person must inherit two copies of the defective NTRK1 gene (one copy from each parent) for the disease to appear. People who inherit a mutated gene from only one parent are called "carriers" of the disease, and they can pass the mutation to their children.
CIPA is extremely rare. While actual incidence is unknown, there are fewer than 100 known cases in the United States. CIPA is more common among people from northern Israel, Ecuador, Sweden, and Japan. Incidence of the disease is higher among people whose parents are closely related to one another (also known as consanguineous).
While there is no cure for CIPA, treatment focuses on the relief of symptoms and the prevention of injury and infection. Many people with CIPA die prematurely because of injuries, fever, or infections.
Anhidrosis, autosomal recessive disorders, CIPA, ectodermal dysplasia, familial dysautonomia type II, hereditary sensory and autonomic neuropathy type IV, HSAN-IV, NGF, nerve growth factor, neurotrophic tyrosine kinase receptor type 1, NTRK1 gene, RTK gene, TRKA gene.