Individuals with this syndrome typically develop normally until reaching the second decade of their lives but the onset of symptoms has been observed as early as age seven. The first defect observed in individuals who suffer from this condition affects the auditory system and is known as bilateral nerve deafness. Another early symptom is the development of myopia (nearsightedness). In addition to bilateral nerve deafness and myopia, other symptoms that plague infected individuals early in disease progression include ataxia, muscle wasting, severe peripheral neuritic pain sometimes accompanied by elevated spinal fluid protein, and joint stiffness.

The central nervous system (CNS) is affected with deficits in the cerebral cortex which indicate signs of mental retardation even though psychological observations appear relatively normal for individuals studied. Atypical epilepsy is also a common feature of CNS malfunctioning including aphasia expressions, blurred vision, and numbness of the face and limbs.

In the third decade of the condition, individuals develop further visual problems including retinitis pigmentosa, and bilateral cataracts. Sufferers endure the restriction of visual fields, night blindness, and eventually severe or complete blindness.

Individuals with this syndrome exhibit many physical deformities including skeletal, epidermal, and subcutaneous abnormalities. The skeletal problems are characterized by scoliosis and muscle weakness indicative of the kyphoscoliotic type which follow muscle wasting and peripheral neuritis (nerve inflammation). Osteoporosis is also observed in many cases. Skin and subcutaneous atrophy is common as well as skin ulcerations due to inability of the skin to heal. One of the final manifestations of disease is baldness.There is no evidence that the progression of Flynn–Aird syndrome shortens the patient's life-span, but the terrible conditions certainly increase morbidity.

Giant axonal neuropathy usually appears in infancy or early childhood, and is progressive. Early signs of the disorder often present in the peripheral nervous system, causing individuals with this disorder to have problems walking. Later, normal sensation, coordination, strength, and reflexes become affected. Hearing or vision problems may also occur. Abnormally kinky hair is characteristic of giant axonal neuropathy, appearing in almost all cases. As the disorder progresses, central nervous system becomes involved, which may cause a gradual decline in mental function, loss of control of body movement, and seizures.

Flynn–Aird syndrome is a rare, hereditary, neurological disease that is inherited in an autosomal dominant fashion. The syndrome involves defects in the nervous, auditory, skeletal, visual, and endocrine systems and encompasses numerous symptoms, bearing striking similarity to other known syndromes of neuroectodermal nature such as: Werner syndrome, Cockayne syndrome and Refsum syndrome.

The onset of Flynn–Aird syndrome typically occurs between ten and twenty years of age, however, the earliest case was diagnosed at age seven. As the syndrome progresses, initial symptoms tend to intensify and new symptoms become apparent. Unlike related syndromes and despite the intensity of symptoms in the disease progression, Flynn–Aird syndrome does not appear to shorten life expectancy.

The disease is characterized by early-onset dementia, ataxia, muscle wasting, skin atrophy, and eye abnormalities. In addition, patients have the potential of developing a number of other related symptoms such as: cataracts, retinitis pigmentosa, myopia (nearsightedness), dental caries, peripheral neuropathy (peripheral nerve damage), deafness, and cystic bone changes. This syndrome was first discovered in the early 1950s by American neurologists P. Flynn and Robert B. Aird who analyzed one family lineage inheritance pattern of this disease.

Patients usually begin to notice symptoms in their 50s and the course is usually slowly progressive. Common features include peripheral neuropathy, cardiomyopathy, and hemolytic anemia. Other features include limb chorea, facial tics, other oral movements (lip and tongue biting), seizures, a late-onset dementia, and behavioral changes.

This is a rare autosomal recessive disorder characterized by early-onset optic atrophy, ataxia, and spasticity.

This disease is a heterogenous group of inherited neuropathies, stemming from a MFN2 mutation, in which both motor and sensory nerves are affected, resulting in distal limb weakness, sensory loss, decreased deep tendon reflexes, and foot deformities. Affected individuals develop progressive optic nerve dysfunction starting later in childhood.

People with CHS have light skin and silvery hair (albinism) and frequently complain of solar sensitivity and photophobia. Other signs and symptoms vary considerably, but frequent infections and neuropathy are common. The infections involve mucous membranes, skin, and the respiratory tract. Affected children are susceptible to infection by Gram-positive and gram-negative bacteria and fungi, with "Staphylococcus aureus" being the most common infection cause. Infections in CHS patients tend to be very serious and even life-threatening. Neuropathy often begins in the teenage years and becomes the most prominent problem. Few patients with this condition live to adulthood.

Most children with Chédiak–Higashi syndrome ultimately reach a stage known as the "accelerated phase", or the "lymphoma-like syndrome", in which defective white blood cells divide uncontrollably and invade many of the body's organs. The accelerated phase is associated with fever, episodes of abnormal bleeding, overwhelming infections, and organ failure. These medical problems are usually life-threatening in childhood.

At the beginning, affected individuals often notice the loss of pain and temperature sensation or all sensory modalities in their feet. As the disease progresses, the sensory abnormalities may extend up to the knees. However, they often do not notice sensory loss for a long time. Many affected individuals only become aware of the disease when they notice painless injuries and burns or when they seek medical advice for slowly healing wounds or foot ulcers. Foot ulcerations may appear due to permanent pressure, such as long walks or badly fitting shoes. Minor wounds or blisters may then lead to deep foot ulcerations. Once infection occurs, complications such as inflammation and destruction of the underlying bones may follow. Affected individuals who do not lose sensation may experience spontaneous pain. In addition, many affected individuals exhibit, to a variable degree, symmetrical distal muscle weakness and wasting.

HSAN I is characterized by marked sensory disturbances mainly as the loss of pain and temperature sensation in the distal parts of the lower limbs. The loss of sensation can also extend to the proximal parts of the lower limbs and the upper limbs as the disease progresses. Some affected individuals do not lose sensation, but instead experience severe shooting, burning, and lancinating pains in the limbs or in the trunk. Autonomic disturbances, if present, manifest as decreased sweating. The degree of motor disturbances is highly variable, even within families, ranging from absent to severe distal muscle weakness and wasting.

The disease progresses slowly, but often disables the affected individuals severely after a long duration. The onset of the disease varies between the 2nd and 5th decade of life, albeit congenital or childhood onset has occasionally been reported. With the progression of the disease, the affected individuals lose the ability to feel pain in their feet and legs. Minor injuries in the painless area can result in slow-healing wounds which, if not immediately recognized, can develop into chronic ulcerations. Once infection occurs, these ulcerations can result in severe complications that lead to foot deformity, such as inflammation of the underlying bones, spontaneous bone fractures, and progressive degeneration of weight-bearing joints. Furthermore, foot deformity promotes skin changes such as hyperkeratosis at pressure points. These complications may necessitate amputation of the affected foot.

Biopsies of severely affected sural nerve (short saphenous nerve) in patients with HSAN I showed evidence of neuronal degeneration. Only a very few myelinated fibers were observed some of which showed a sign of primary (segmental) demyelination. A reasonable number of unmyelinated axons remained, although the presence of stacks of flattened Schwann cell processes suggested unmyelinated axon loss. Electrophysiological testing provides additional evidence that neuronal degeneration underlies the disease. Sensory potentials are usually absent in the lower limbs but are often recordable or even normal in the upper limbs of the patients. In addition, motor conduction is slow, possibly implying a demyelinating process.

Hereditary sensory and autonomic neuropathy type I (HSAN I) or hereditary sensory neuropathy type I (HSN I) is a group of autosomal dominant inherited neurological diseases that affect the peripheral nervous system particularly on the sensory and autonomic functions. The hallmark of the disease is the marked loss of pain and temperature sensation in the distal parts of the lower limbs. The autonomic disturbances, if present, manifest as sweating abnormalities.

The beginning of the disease varies between adolescence and adulthood. Since affected individuals cannot feel pain, minor wounds or blisters in the painless area may not be immediately recognized and can develop into extensive and deep foot ulcerations. Once infection occurs, the complications such as inflammation and progressive destruction of the underlying bones may follow and may require amputation of the surrounding area.

HSAN I is the most common type among the five types of HSAN. As a heterogeneous group of diseases, HSAN I can be divided into five subtypes HSAN IA-E. Most of the genes associated with the diseases have been identified. However, the molecular pathways leading to the manifestation of the diseases are not fully understood. Therefore, the potential targets for therapeutic interventions are not known. Moreover, gene-based therapies for patients with the diseases are not available to date, hence supportive care is the only treatment available for the patients.

Symptoms of the Roussy–Lévy syndrome mainly stem from nerve damage and the resulting progressive muscle atrophy. Neurological damage may result in absent tendon reflexes (areflexia), some distal sensory loss and decreased excitability of muscles to galvanic and faradic stimulation. Progressive muscle wasting results in weakness of distal limb muscles (especially the peronei), gait ataxia, pes cavus, postural tremors and static tremor of the upper limbs, kyphoscoliosis, and foot deformity.

These symptoms frequently translate into delayed onset of ability to walk, loss of coordination and balance, foot drop, and foot-bone deformities. They are usually first observed during infancy or early childhood, and slowly progress until about age 30, at which point progression may stop in some individuals, or symptoms may continue to slowly progress.

Giant axonal neuropathy is a rare, autosomal recessive neurological disorder that causes disorganization of neurofilaments. Neurofilaments form a structural framework that helps to define the shape and size of neurons and are essential for normal nerve function.

Like other mitochrondrial diseases, "MNGIE is a multisystem disorder". MNGIE primarily affects the gastrointestinal and neurological systems. Gastrointestinal symptoms may include gastrointestinal dysmotility, due to inefficient peristalsis, which may result in pseudo-obstruction and cause malabsorption of nutrients. Additionally, gastrointestinal symptoms such as borborygmi, early satiety, diarrhea, constipation, gastroparesis, nausea, vomiting, weight loss, and diverticulitis may be present in MNGIE patients. Neurological symptoms may include diffuse leukoencephalopathy, peripheral neuropathy, and myopathy. Ocular symptoms may include retinal degeneration, ophthalmoplegia, and ptosis. Those with MNGIE are often thin and experience continuous weight loss. The characteristic thinness of MNGIE patients is caused by multiple factors including inadequate caloric intake due to gastrointestinal symptoms and discomfort, malabsorption of food from bacterial overgrowth due to decreased motility, as well as an increased metabolic demand due to inefficient production of ATP by the mitochondria.

McLeod syndrome (or McLeod phenomenon; ) is an X-linked recessive genetic disorder that may affect the blood, brain, peripheral nerves, muscle, and heart. It is caused by a variety of recessively inherited mutations in the XK gene on the X chromosome. The gene is responsible for producing the Kx protein, a secondary supportive protein for the Kell antigen on the red blood cell surface.

There are several manifestations of Chédiak–Higashi syndrome as mentioned above; however, neutropenia seems to be the most common. The syndrome is associated with oculocutaneous albinism. Persons are prone for infections, especially with "Staphylococcus aureus", as well as "Streptococci".

It is associated with periodontal disease of the deciduous dentition. Associated features include abnormalities in melanocytes (albinism), nerve defects, bleeding disorders.

Autosomal dominant optic atrophy can present clinically as an isolated bilateral optic neuropathy (non-syndromic form) or rather as a complicated phenotype with extra-ocular signs (syndromic form).

Dominant optic atrophy usually affects both eyes roughly symmetrically in a slowly progressive pattern of vision loss beginning in childhood and is hence a contributor to childhood blindness. Vision testing will reveal scotomas (areas of impaired visual acuity) in the central visual fields with peripheral vision sparing and impaired color vision (color blindness). Visual acuity loss varies from mild to severe, typically ranging from 6/6 (in meters, equivalent to 20/20, ft) to 6/60 (20/200, ft) with a median value of 6/36 (roughly equivalent to 20/125 ft), corrected vision. In rare cases, vision loss is more severe.

Characteristic changes of the fundus evident on examination is temporal pallor (indicating atrophy) of the optic disc and in its end stage, excavation of the optic disc, as is also seen in Leber hereditary optic neuropathy and normal tension glaucoma.

Because the onset of Dominant optic atrophy is insidious, symptoms are often not noticed by the patients in its early stages and are picked up by chance in routine school eye screenings. First signs of Kjer's typically present between 4–6 years of age, though presentation at as early as 1 year of age has been reported. In some cases, Dominant optic atrophy may remain subclinical until early adulthood.

Progression of dominant optic atrophy varies even within the same family. Some have mild cases with visual acuity stabilizing in adolescence, others have slowly but constantly progressing cases, and others still have sudden step-like decreases in visual acuity. Generally, the severity of the condition by adolescence reflects the overall level of visual function to be expected throughout most of the patient’s adult life (Votruba, 1998). Slow decline in acuity is known to occur in late middle age in some families.

In complicated cases of autosomal dominant optic atrophy, in addition to bilateral optic neuropathy, several other neurological signs of neurological involvement can be observed: peripheral neuropathy, deafness, cerebellar ataxia, spastic paraparesis, myopathy.

Onset occurs in infancy or early childhood, usually before 3 years of age. Progression is slow until the teenage years at which point it may accelerate, resulting in severe disability.

Symptoms are usually more severe and rapidly progressive than in the other more common Charcot–Marie–Tooth diseases. Some patients may never walk and solely use wheelchairs by the end of their first decade, while others may need only a cane (walking stick) or similar support through life.

Dejerine–Sottas disease is characterized by moderate to severe lower and upper extremity weakness and loss of sensation, which occur mainly in the lower legs, forearms, feet and hands. Loss of muscle mass and reduced muscle tone can occur as the disease progresses. Other symptoms may include pain in the extremities, curvature of the spine, clawed hands, foot deformities, ataxia, peripheral areflexia, and slow acquisition of motor skills in childhood. Symptoms that are less common can include limitation of eye movements, other eye problems such as nystagmus or anisocoria, or mild hearing loss.

Roussy–Lévy syndrome, also known as Roussy–Lévy hereditary areflexic dystasia, is a rare genetic disorder of humans that results in progressive muscle wasting. It is caused by mutations in the genes that code for proteins necessary for the functioning of the myelin sheath of the neurons, affecting the conductance of nerve signals and resulting in loss of muscles' ability to move.

The condition affects people from infants through adults and is inherited in an autosomal dominant manner. Currently, no cure is known for the disorder.

Mitochondrial neurogastrointestinal encephalopathy syndrome (MNGIE) is a rare autosomal recessive mitochondrial disease. It has been previously referred to as polyneuropathy, ophthalmoplegia, leukoencephalopathy, and POLIP syndrome. The disease presents in childhood, but often goes unnoticed for decades. Unlike typical mitochondrial diseases caused by mitochondrial DNA (mtDNA) mutations, MNGIE is caused by mutations in the TYMP gene, which encodes the enzyme thymidine phosphorylase. Mutations in this gene result in impaired mitochondrial function, leading to intestinal symptoms as well as neuro-ophthalmologic abnormalities. "A secondary form of MNGIE, called MNGIE without leukoencephalopathy, can be caused by mutations in the POLG gene".

Dominant optic atrophy, or dominant optic atrophy, Kjer's type, is an autosomally inherited disease that affects the optic nerves, causing reduced visual acuity and blindness beginning in childhood. This condition is due to mitochondrial dysfunction mediating the death of optic nerve fibers. Dominant optic atrophy was first described clinically by Batten in 1896 and named Kjer’s optic neuropathy in 1959 after Danish ophthalmologist Poul Kjer, who studied 19 families with the disease. Although dominant optic atrophy is the most common autosomally inherited optic neuropathy (i.e., disease of the optic nerves) aside from glaucoma, it is often misdiagnosed.

An individual displaying MERRFs syndrome will manifest not only a single symptom, but regularly patients display more than one affected body part at a time. It has been observed that patients with MERRF syndrome will primarily display Myoclonus as a first symptom, along with it they can also manifest seizures, cerebellar ataxia and myopathy. Secondary features include dementia, optic atrophy, bilateral deafness, peripheral neuropathy, spasticity or multiple lipomata. Additional symptoms include dementia, optic atrophy, bilateral deafness and peripheral neuropathy, spasticity, lipomatosis, and/or cardiomyopathy with wolff parkinson-white syndrome. Most patients will not exhibit all of these symptoms, however more than one of these symptoms will be present in a patient who has been diagnosed with MERRFS disease. Due to the multi-symptoms presented by the individual, the severity of the syndrome is very difficult to evaluate. Mitochondrial disorders may present at any age, and this holds truth for MERRS, since it forms part of them. Therefore, if a patient is presenting some of these symptoms, the doctor is able to narrow it down to MEERF mitochondrial disorder.

MERRF syndrome (or myoclonic epilepsy with ragged red fibers) is a mitochondrial disease. It is extremely rare, with an estimated prevalence of 1/4,000 in Northern Europe, and has varying degrees of expressivity owing to heteroplasmy. MERRF syndrome affects different parts of the body, particularly the muscles and nervous system. The signs and symptoms of this disorder appear at an early age, generally childhood or adolescence. The causes of MERRF syndrome is difficult to determine, however since its a mitochondrial disorder it can be caused by the mutation of nuclear DNA or mitochondrial DNA. The classification of this disease varies from patient to patient, since many individuals do not fall into one specific disease category.The primary features displayed on a person with MERRF include myoclonus, seizures, cerebellar ataxia, myopathy and ragged ref fibers (RRF) on muscle biopsy, leading to the diseases name. Secondary features include dementia, optic atrophy, bilateral deafness, peripheral neuropathy, spasticity or multiple lipomata. Mitochondrial disorders may present at any age, and this holds truth for MERRFS, since it forms part of them.

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV (HSAN IV), is characterized by insensitivity to pain, anhidrosis (the inability to sweat), and intellectual disability. The ability to sense all pain (including visceral pain) is absent, resulting in repeated injuries including: oral self-mutilation (biting of tongue, lips, and buccal mucosa); biting of fingertips; bruising, scarring, and infection of the skin; multiple bone fractures (many of which fail to heal properly); and recurrent joint dislocations resulting in joint deformity. Sense of touch, vibration, and position are normal. Anhidrosis predisposes to recurrent febrile episodes that are often the initial manifestation of CIPA. Hypothermia in cold environments also occurs. Intellectual disability of varying degree is observed in most affected individuals; hyperactivity and emotional lability are common.

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. Intellectual disability is usually present.

Type 4, congenital insensitivity to pain with anhidrosis (CIPA), is an autosomal recessive condition and affected infants present with episodes of hyperthermia unrelated to environmental temperature, anhidrosis and insensitivity to pain. Palmar skin is thickened and charcot joints are commonly present. NCV shows motor and sensory nerve action potentials to be normal. The histopathology of peripheral nerve biopsy reveals absent small unmyelinated fibers and mitochondria are abnormally enlarged.

Management of Hereditary sensory and autonomic neuropathy Type 4:

Treatment of manifestations: Treatment is supportive and is best provided by specialists in pediatrics, orthopedics, dentistry, ophthalmology, and dermatology. For anhidrosis: Monitoring body temperature helps to institute timely measures to prevent/manage hyperthermia or hypothermia. For insensitivity to pain: Modify as much as reasonable a child’s activities to prevent injuries. Inability to provide proper immobilization as a treatment for orthopedic injuries often delays healing; additionally, bracing and invasive orthopedic procedures increase the risk for infection. Methods used to prevent injuries to the lips, buccal mucosa, tongue, and teeth include tooth extraction, and/or filing (smoothing) of the sharp incisal edges of teeth, and/or use of a mouth guard. Skin care with moisturizers can help prevent palmar and plantar hyperkeratosis and cracking and secondary risk of infection; neurotrophic keratitis is best treated with routine care for dry eyes, prevention of corneal infection, and daily observation of the ocular surface. Interventions for behavioral, developmental, and motor delays as well as educational and social support for school-age children and adolescents are recommended.

Prevention of secondary complications: Regular dental examinations and restriction of sweets to prevent dental caries; early treatment of dental caries and periodontal disease to prevent osteomyelitis of the mandible. During and following surgical procedures, potential complications to identify and manage promptly include hyper- or hypothermia and inadequate sedation, which may trigger unexpected movement and result in secondary injuries.

Familial dysautonomia is a genetic disorder that affects the development and survival of certain nerve cells. The disorder disturbs cells in the autonomic nervous system, which controls involuntary actions such as digestion, breathing, production of tears, and the regulation of blood pressure and body temperature. It also affects the sensory nervous system, which controls activities related to the senses, such as taste and the perception of pain, heat, and cold. Familial dysautonomia is also called hereditary sensory and autonomic neuropathy, type III.

Problems related to this disorder first appear during infancy. Early signs and symptoms include poor muscle tone (hypotonia), feeding difficulties, poor growth, lack of tears, frequent lung infections, and difficulty maintaining body temperature. Older infants and young children with familial dysautonomia may hold their breath for prolonged periods of time, which may cause a bluish appearance of the skin or lips (cyanosis) or fainting. This breath-holding behavior usually stops by age 6. Developmental milestones, such as walking and speech, are usually delayed, although some affected individuals show no signs of developmental delay.

Additional signs and symptoms in school-age children include bed wetting, episodes of vomiting, reduced sensitivity to temperature changes and pain, poor balance, abnormal curvature of the spine (scoliosis), poor bone quality and increased risk of bone fractures, and kidney and heart problems. Affected individuals also have poor regulation of blood pressure. They may experience a sharp drop in blood pressure upon standing (orthostatic hypotension), which can cause dizziness, blurred vision, or fainting. They can also have episodes of high blood pressure when nervous or excited, or during vomiting incidents. About one-third of children with familial dysautonomia have learning disabilities, such as a short attention span, that require special education classes. By adulthood, affected individuals often have increasing difficulties with balance and walking unaided. Other problems that may appear in adolescence or early adulthood include lung damage due to repeated infections, impaired kidney function, and worsening vision due to the shrinking size (atrophy) of optic nerves, which carry information from the eyes to the brain.

Type 3, familial dysautonomia (FD) or Riley-Day syndrome, is an autosomal recessive disorder seen predominantly in Jews of eastern European descent. Patients present with sensory and autonomic disturbances. Newborns have absent or weak suck reflex, hypotonia and hypothermia. Delayed physical development, poor temperature and motor incoordination are seen in early childhood. Other features include reduced or absent tears, depressed deep tendon reflexes, absent corneal reflex, postural hypotension and relative indifference to pain. Scoliosis is frequent. Intelligence remains normal. Many patients die in infancy and childhood. Lack of flare with intradermal histamine is seen. Histopathology of peripheral nerve shows reduced number of myelinated and non-myelinated axons. The catecholamine endings are absent.

Genes related to Hereditary sensory and autonomic neuropathy Type 3:

Mutations in the IKBKAP gene cause familial dysautonomia.

The IKBKAP gene provides instructions for making a protein called IKK complex-associated protein (IKAP). This protein is found in a variety of cells throughout the body, including brain cells.

Nearly all individuals with familial dysautonomia have two copies of the same IKBKAP gene mutation in each cell. This mutation can disrupt how information in the IKBKAP gene is pieced together to make a blueprint for the production of IKAP protein. As a result of this error, a reduced amount of normal IKAP protein is produced. This mutation behaves inconsistently, however. Some cells produce near normal amounts of the protein, and other cells—particularly brain cells—have very little of the protein. Critical activities in brain cells are probably disrupted by reduced amounts or the absence of IKAP protein, leading to the signs and symptoms of familial dysautonomia.

The signs and symptoms of POEMS syndrome are highly variable. This often leads to long delays (e.g. 13–18 months) between the onset of initial symptoms and diagnosis. In addition to the signs and symptoms indicated by the POEMS acronym, the PEST acronym is used to describe some of the other signs and symptoms of the disease. PEST stands for Papilledema, evidence of Extravascular volume overload (ascites, pleural effusion, pericardial effusion, and lower extremity edema), Sclerotic bone lesions, and Thrombocytosis/erythrocytosis (i.e. increased in blood platelets and red blood cells). Other features of the disease include a tendency toward leukocytosis, blood clot formation, abnormal lung function (restrictive lung disease, pulmonary hypertension, and impaired lung diffusion capacity), very high blood levels of the cytokine vascular endothelial growth factor (VEGF), and an overlap with the signs and symptoms of multicentric Castleman disease.

Dejerine–Sottas disease, also known as Dejerine–Sottas syndrome, Dejerine–Sottas neuropathy, progressive hypertrophic interstitial polyneuropathy of childhood and onion bulb neuropathy (and, "hereditary motor and sensory polyneuropathy type III" and "Charcot–Marie–Tooth disease type 3"), is a hereditary neurological disorder characterised by damage to the peripheral nerves and resulting progressive muscle wasting. The condition is caused by mutations in a various genes and currently has no known cure.

The disorder is named for Joseph Jules Dejerine and Jules Sottas, French neurologists who first described it.