About hsan iv

What is hsan iv?

The hereditary sensory neuropathies (HSN) include 4-6 similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. The classification of these diseases is complicated, and sometimes a source of disagreement among the experts.

Hereditary sensory neuropathy type IV (HSN4) is a rare genetic disorder characterized by the loss of sensation (sensory loss), especially in the feet and legs and, less severely, in the hands and forearms. The sensory loss is due to abnormal functioning of small, unmyelinated nerve fibers and portions of the spinal cord that control responses to pain and temperature as well as other involuntary or automatic body processes. Sweating is almost completely absent with this disorder. Mental retardation is usually present.

The disorder is inherited as an autosomal recessive trait. The gene involved is located on chromosome 1.

HSNs of various types may attack a single nerve (mononeuropathy) or many nerves simultaneously (polyneuropathy). The resulting symptoms may involve sensory, motor, reflex, or blood vessel (vasomotor) functions.

What are the symptoms for hsan iv?

Loss of feeling symptom was found in the hsan iv condition

The symptoms of HSNs are highly variable, even among members of the same family. HSNs of various types may attack a single nerve (mononeuropathy) or many nerves simultaneously (polyneuropathy). The resulting symptoms may involve sensory, motor, reflex or blood vessel (vasomotor) function.

Although researchers have been able to establish HSANs as a distinct group of disorders with characteristic or “core” symptoms, much about these disorders is not fully understood. Several factors including the small number of identified patients, the lack of large clinical studies, and the possibility of other genes influencing the disorder prevent physicians from developing an accurate picture of associated symptoms and prognosis of all subtypes. Many of the reported individuals of HSAN2 are inconsistent in terms of symptomology and progression. This is partially caused by case reports that include cases that are not molecularly confirmed to be HSAN2. Consequently, it is important to note that affected individuals may not have all of the symptoms discussed below. Parents should talk to their children’s physician and medical team about their specific case, associated symptoms, and overall prognosis.

HSAN2 is characterized by sensory loss of the distal portions of the legs. Distal refers to those areas that are farther from the center of the body and includes the lower arms and legs and the hands and feet. The legs and feet are more severely affected than the arms and hands. Onset is usually shortly after birth or during childhood.

Affected individuals may experience progressive Numbness and tingling in the hands and feet. They may also experience reduced sensation to temperature, Pain and touch. Eventually, affected individuals will be unable to distinguish between cold or warm stimuli and be unable to feel Pain in the affected area. Because of the loss of sensation, affected individuals may develop chronic skin erosions, ulcers (open sores), or blisters that are slow to heal. These normally painful conditions do not hurt because of the loss of sensation. If unrecognized and left untreated, these painless injuries can progress to cause more serious complications such as recurrent infections. Eventually, affected individuals can develop infection of the surrounding bone (osteomyelitis), loss of bone and tissue in the fingers and toes (acroosteolysis), spontaneous, painless fractures, and inflammation and damage to the surrounding joints (neuropathic arthropathy).

Most reports describe autonomic problems as less pronounced than sensory abnormalities in individuals with HSAN2. Many affected individuals have Sweating abnormalities including episodes of excessive Sweating (hyperhidrosis), reduced Sweating (hypohidrosis), or an inability to sweat (anhidrosis). Individuals can experience hyperhidrosis along with patchy areas of anhidrosis. Hyperhidrosis can also lead to excessive tear production. Additional autonomic findings include backflow of the stomach contents into the esophagus (gastroesophageal reflux) and low blood pressure upon standing (postural hypotension) causing lightheadedness or dizziness.

Some individuals with HSAN2 exhibit self-mutilation, usually around the time of the eruption of primary teeth. Additional symptoms have been reported in some patients including dry scaly patches on the skin of the palms and soles (hyperkeratosis), diminished taste sensation, diminishment of certain reflexes, and abnormal sideways curvature of the spine (scoliosis). Some infants and children may have difficulty swallowing. Sleep apnea, in which breathing slows or stops briefly during sleep, may also occur. Later in the course of the disorder, urinary incontinence or signs of spasticity may develop.

What are the causes for hsan iv?

HSAN2 is caused by a mutation in the one of four genes. HSAN2A is caused by mutations in the WNK1 gene, HSAN2B is caused by mutations in the FAM134B gene, lately renamed to RETREG1. HSAN2C is caused by mutations in the KIF1A gene, HSAN2D is caused by mutations in the SCN9A gene. Genes provide instructions for creating proteins that play a critical role in many functions of the body. When a mutation of a gene occurs, the protein product may be faulty, inefficient, or absent. Depending upon the functions of the particular protein, this can affect many organ systems of the body.

HSAN2 is an autosomal recessive genetic condition. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent. If an individual receives one working gene and one non-working gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the non-working gene and, therefore, have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% with each pregnancy. The chance for a child to receive working genes from both parents is 25%. The risk is the same for males and females.

What are the treatments for hsan iv?

The treatment of HSAN2 is directed toward the specific symptoms that are apparent in each individual. Treatment may require the coordinated efforts of a team of specialists. Pediatricians, orthopedists, orthopedic surgeons, dermatologists, physiotherapists, and other healthcare professionals may need to systematically and comprehensively plan an affect child’s treatment. Genetic counseling is recommended for affected individuals and their families.

Prompt recognition and treatment of wounds on affected areas (e.g. the feet) is critically important. Ulceration of the feet of individuals with HSAN2 is extremely similar to ulcers found on the feet of individuals with diabetic neuropathy. Therefore, the treatment of foot ulcerations and infections may follow similar guidelines. Such treatment can include medical removal of diseased skin and tissue (debridement), applying medications and dressing to the wound, and keeping the wound clean and bandaged. Antibiotics may be used to treat infection. Affected individuals should receive instruction on proper care of their feet including avoiding risk factors for developing foot ulceration such as removing sources of pressure (e.g. shoes with pressure points). It is recommended that affected individuals receive routine foot care from a diabetic clinic or a podiatrist familiar with the treatment of diabetic foot ulcers.

Additional treatment is symptomatic and supportive.

What are the risk factors for hsan iv?

HSAN2 affects males and females in equal numbers. The exact incidence and prevalence is unknown. HSAN2 may go misdiagnosed or undiagnosed, making it difficult to determine the disorder’s true frequency in the general population.

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