Congenital touch neuropathy with angidrozy
Congenital touch neuropathy with angidrozy – extremely rare hereditary disease which is characterized by violations of a peripheral innervation and processes of sweating. One of the main symptoms of this state are total absence of notsitseptivny sensitivity, the increased body temperature because of the broken thermal control, attacks of sudden short wind. Diagnosis of a disease is based on data of fizikalny survey, check of reaction of an organism to various external irritants, genetic researches. Treatment of congenital touch neuropathy with angidrozy does not exist, but patients demand special leaving.
Congenital touch neuropathy with angidrozy
Congenital touch neuropathy with angidrozy (a family dizavtonomiya of type 2, congenital tolerance to pain with angidrozy Svensson) – very rare genetic pathology caused by violations of an innervation and notsitseptivny sensitivity. The first messages on this state appeared in 1932, several families from Pakistan which members had full tolerance to pain, tendency to self-damages and the increased body temperature were revealed. Today it is not possible to define occurrence of this disease because of its big rarity, all about one hundred patients with congenital touch neuropathy with angidrozy are described. The mechanism of inheritance of this state autosomno-recessive, men and women are surprised with an identical share of probability. In general the family dizavtonomiya of type 2 is of huge interest because of disclosure of genetic aspects of pain and an opportunity on this basis to create anesthetics of new generation to modern genetics and medicine.
The reasons of congenital touch neuropathy with angidrozy
Two main genes in which mutations are responsible for development of this pathology are revealed. The first of them, NTRK1 is located on the 1st chromosome and codes a special receptor of nervous tissues (a receptor of a tyrosinekinase of the 1st type). This protein is sensitive to a factor of growth of nerves and at violation of the structure caused by NTRK1 gene mutation is not capable to perform the functions fully. As a result of it development of holinergichesky neurons, cages of sympathetic nervous system, sensitive ways in back backs of a spinal cord is broken. Also processes of a miyelinization of peripheral fibers are at a loss. All this leads to the fact that there is impossible a holinergichesky innervation of sweat glands and carrying out painful nervous impulses at preservation of tactile, temperature and flavoring sensitivity. The mechanism of inheritance of mutations of a gene NTRK1 – autosomno-recessive, according to some information its defects cause the most part of cases of congenital touch neuropathy with angidrozy.
The second gene which mutations are associated with this disease is SCN9A localized on the 2nd chromosome. A product of its expression is special protein (Nav1.7) relating to group of sodium channels of neurons. It is revealed that on membranes of neurons of notsitseptivny system the greatest number of such channels is observed, but their concrete functions are unknown there. The disease caused by SCN9A gene mutation is also characterized by total loss of painful sensitivity, however other symptoms, such as temperature increase, intellectual backwardness are expressed much more weakly. Therefore clinically the current of such form of congenital touch neuropathy with angidrozy is more favorable.
Symptoms of congenital touch neuropathy with angidrozy
The leading symptom of this disease is total absence of notsitseptivny sensitivity – patients since the birth do not feel pain and cannot even imagine this feeling. They can feel a touch, cold, heat – but there is even no pain when on skin the burn already develops. Fractures of bones, traumatizing skin and other parts of a body can be felt, but patients do not describe the feelings as unpleasant. As a result of it in the childhood they quite often observe an autoaggression – especially often patients bite lips, language, can put themselves other damages. It can remain also at adult age, especially if congenital touch neuropathy with angidrozy is followed by intellectual backwardness – it is characteristic of the states caused by NTRK1 gene mutations.
At patients the increased body temperature, sometimes with fever episodes to 40-41 °C which does not react to reception of traditional febrifuges is constantly observed. It is caused by sweating violations therefore there is no usual cooling of a body. Also changes of integuments are for the same reason observed – to the touch they hot and dry, skin thin, often easily gathers in folds. Among other, less constant symptoms of congenital touch neuropathy with angidrozy, allocate early loss of teeth, the increased risk of development of osteomyelitis, necroses of bones and joints. The reason of these changes lies in violations of an innervation of a number of structures, an important role is played also by the late address of patients to the expert – one of symptoms of osteomyelitis or a necrosis of a bone is pain which patients are not capable to feel. In rare instances ophthalmologic violations – , existence of erosion and ulcers of a cornea can come to light.
Diagnosis of congenital touch neuropathy with angidrozy
For definition of this state apply a set of techniques – fizikalny survey, diagnostic tests to identification of an angidroz, genetic researches, studying of the hereditary anamnesis. At survey of patients autoaggression signs – strongly injured lips and language with traces from teeth (often come to light up to lack of its part), there can be fresh and old cuts on a body and extremities, signs of the begun to live changes. However injuries of a skeleton or muscles can be caused also by the fact that at physical activity patients are not capable to estimate correctly effort and at the same time tear muscles, sheaves or break bones. Body temperature is increased, integuments dry, intellectual backwardness of various degree can be observed. Patients feel touches, have normal temperature sensitivity, but pricks a needle do not perceive as pain, and estimate them as touch option rather.
When conducting diagnostic tests stalemate reactions to any irritants – electrostimulation or pilokarpinovy test completely negative are not noted. At temperature increase of the environment sweating also does not happen, but the body temperature of the patient because of the complicated thermolysis begins to rise. The electromyography does not find conductivity violations, all reflexes are completely kept except for kornealny – it is sharply lowered or is even absent, it is one of important symptoms of congenital touch neuropathy with angidrozy.
Studying of the hereditary anamnesis often confirms the family nature of a disease, genetic diagnostics comes down to a direct sekvenirovaniye of a gene of NTRK1 for the purpose of identification of mutations. Some laboratories are capable to make the similar procedure and concerning SCN9A gene. The doctor geneticist can also run for search of a pathological gene at a fenotipicheska of healthy carriers (in case of existence of congenital touch neuropathy with angidrozy at relatives) or to perform prenatal diagnostics by means of amniocentesis or a biopsy a horiona.
Treatment and the forecast of congenital touch neuropathy with angidrozy
Specific treatment of congenital touch neuropathy with angidrozy does not exist. Since the early childhood special patient care is necessary – to stop self-damages (biting of lips, language), to watch carefully a condition of bone and muscular system, to control body temperature. At development of fever or an overheat it is possible to eliminate a hyperthermia only with physical methods – a cold shower, use of bubbles with ice, rubdown by cold water. If there are signs mental retardation, then the patient has to be under constant supervision, in case of the kept intelligence the adult with such disease theoretically can control the disease. At the correct leaving and a healthy lifestyle the forecast concerning the patient's life favorable.