What is ANE? | ANE International (2024)

Symptoms

Initially, symptoms specific to viral infection include fever, cough, vomiting, diarrhoea,sore throat or rash. After a few days, there is a rapid neurological deterioration with seizures and altered consciousness (from drowsiness and confusion to coma).

Diagnosis

Brain scans (Computed Tomography – CT and Magnetic Resonance Imaging-MRI) show symmetric multifocal lesions affecting the brain (thalami, brainstem, periventricular white matter and cerebellum are the most common although other areas may be affected). The bilateral thalamic lesions are a distinctive feature of ANE. The spinal cord is rarely involved.

Cerebrospinal fluid (CSF) testing shows elevated protein, but very rarely pleocytosis (increased cell count). Sometimes, pathogens (viruses) responsible for infection are found in the CSF.

Diagnosis is made based on the presence of viral infection before the development of ANE, signs of rapidly neurological deterioration, the results of the brain scans (specifically the symmetric multifocal lesions) and CSF testing and exclusion of resembling diseases.

Pathogenesis

(How the disease happens).

The exact mechanism of the disease is not yet known. It is presumed to be an immune-mediated process triggered by the viral infection. In other words, people with ANE often may have an exaggerated immune response to various infections.

ANE is not considered to be an inflammatory encephalitis as there are no signs of infection in the CSF or the brain (as seen in autopsies, when performed).

Prognosis

The clinical course and the prognosis vary from patient to patient, ranging from a mild form with complete recovery (10%) to a severe form with a high mortality (30%). Most of the survivors are left with neurological sequelae (e.g. motor deficits, epilepsy, developmental delay). Poor prognosis is associated with delayed diagnosis, involvement of brainstem (part of the brain that connects the brain with the spinal cord and controls the heart and lung functions) and recurrent episodes. Recurrent or familial ANE without the RANBP2 mutation has a more severe outcome and greater predilection for males than that with the RANBP2 mutation. This suggests that there are unknown gene mutations linked to ANE.

ANE has the 2nd in the mortality rates and is another distinct neurological complication of influenza infection with reported mortality rates of 30%–40% second only to historical descriptions of encephalitis lethargica (60%) among neurologic complications of influenza.

Treatment

There are no set guidelines for treating ANE. Treatment usually includes:

intensive care to help the patient perform their usual bodily functions (breathing machine, tubes and drips),
symptomatic treatment (e.g. antiepileptic drugs), immunotherapies (e.g. IV glucocorticoids, immunoglobulin, and plasmapheresis),therapeutic hypothermia (reduction of the body temperature done on purpose).

Recurrent and Familial Cases- ANE1

Most cases of ANE are isolated events and do not happen again. However, in some patients, the illness can re-occur and/or it can present itself in other family members. This type of ANE is called ANE1 or Infection-Induced Acute Encephalopathy-3 (IIAE3). It has been linked with mutations in the RANBP2 gene. The mutation of this gene has been detected in 75% of ANE family cases. However, the mutation in this gene is a risk factor in the occurrence of the disease and doesn’t imply that all individuals affected will develop ANE1. Half of them will suffer from ANE1 and half will be asymptomatic carriers. Additional genetic and environmental factors (viral infection) are also required for the disease to develop.

RanBP2 Mutation

It is becoming more common to have ANE patients and their families tested for a gene mutation. It is important to note, however, that even with the gene mutation, not all mutations will result in ANE. The actual trigger has yet to be determined. Probability of recurrence after the first episode, is 50% on trigger activation (ie. Influenza; HSV) and then 25% after a second episode. Note that triggers vary from one patient to the next. Some patients will only have 1 trigger while others will have multiple.

At least three mutations in the RANBP2 gene have been found to increase the risk of developing acute necrotizing encephalopathy type 1 (ANE1). These mutations change single protein building blocks (amino acids) in the gene’s protein resulting in the production of a protein that cannot function properly. The mutations do not cause health issues on their own; it is not clear how they are involved in the process of a viral infection triggering neurological damage.

Further Information At: https://ghr.nlm.nih.gov/gene/RANBP2#conditions

HLA Genotypes (In Japanese Patients)

Whilst the mutation of the RANBP2 gene has been confirmed to be associated with ANE, the involvement of HLA genotypes has not at this point. However, a recent study confirms the likelihood. ANE has been reported worldwide, but this disease is reported predominantly in children living in East Asian countries. The difference in occurence among various ethnic groups suggests the involvement of host genetic factors in ANE. Using 31 Japanese confirmed ANE patients a study was conducted in Japan and aimed for the first time to investigate genetic background of ANE within this ethnic group. Human leukocyte antigen (HLA) genotypes include HLA class I (HLA-A, -C and -B) and class II (HLA-DR, -DQ and -DP). These molecules play an important role in the immune response. The study focused on HLA genotypes as a predisposing factor to ANE based on the fact that the abnormal innate immune reaction was provoked by a preceding infection. In addition, HLA have been reported to be associated with various diseases susceptibility, such as autoimmune diseases and infectious diseases.

At the conclusion of the study there was enough evidence to support the above but due to the rarity of ANE the availability of statistics were limited. Further similar studies are required to confirm these findings. The data from this particular study suggests that specific HLA Genotypes are involved in the manner of development of ANE.

Read Full Article At: http://www.nature.com/gene/journal/v17/n6/full/gene201632a.html

What is ANE? | ANE International (2024)

FAQs

What is ANE? | ANE International? ›

ANE International aims to raise awareness, support families & educate about the disease Acute Necrotizing Encephalopathy. Families affected by ANE established ANE International in 2016. # ANEawareness #ANEandUs.

What causes acute necrotizing encephalopathy? ›

Influenza is the most common virus found in people with acute necrotizing encephalopathy type 1; other viruses that are known to trigger this condition include human herpesvirus 6, coxsackie virus, and enteroviruses. In rare cases, the bacterium Mycoplasma pneumoniae is involved.

What disease is ANE? ›

Acute necrotizing encephalopathy (ANE) is a rare disease characterized by brain damage (encephalopathy) that usually follows an acute febrile disease, mostly viral infections..

What is ANE syndrome? ›

Alopecia, neurologic defects, and endocrinopathy syndrome (ANES) is an autosomal recessive disorder characterized by alopecia with skin involvement including multiple facial nevi and flexural hyperpigmentation; moderately to severely impaired intellectual development; progressive motor decline; and endocrine deficiency ...

What are the symptoms of ANEC? ›

The clinical manifestations of ANEC are highly complex and diverse, and the course of the disease is rapid. Typical symptoms include high fever, headache, altered consciousness, seizures, hypomyotonia, and brainstem dysfunction.

What is the survival rate for acute necrotizing encephalopathy? ›

Prognosis. Approximately one-third of individuals with acute necrotizing encephalopathy do not survive their illness and subsequent neurological decline. Of those who do survive, about half have permanent brain damage due to tissue necrosis, resulting in impairments in walking, speech, and other basic functions.

What is the life expectancy of someone with encephalitis? ›

As with treatment, autoimmune encephalitis recovery depends mainly on the specific clinical case, the form of encephalitis, and the after-effects of the disease. However, the autoimmune encephalitis life expectancy after encephalitis, in general, ranges from 60 to 90 years in different countries.

What is the life expectancy of someone with Henekam syndrome? ›

The signs and symptoms of Hennekam syndrome vary widely among affected individuals, even those within the same family. Life expectancy depends on the severity of the condition and can vary from death in childhood to survival into adulthood.

What is the life expectancy of someone with BVVL syndrome? ›

There are three documented cases of BVVL where the patient died within the first five years of the disease. On the contrary, most patients have survived more than 10 years after the onset of their first symptom, and several cases have survived 20–30 years after the onset of their first symptom.

What is the life expectancy of ARID1B syndrome? ›

Prognosis. It is unknown if life span in individuals with ARID1B-RD is abnormal. One reported individual is alive at age 51 years [Santen, personal observation], and a woman age 60 years has also been reported [Määttänen et al 2018], demonstrating that survival into adulthood is possible.

What is the mortality rate for ANEC? ›

Treatment and prognosis

Acute necrotizing encephalitis carries a very poor prognosis; the mortality rate is near 70%.

What are the cardinal signs of encephalopathy? ›

Additional symptoms may include:
  • Hallucinations.
  • Involuntary muscle movements such as jerks, tremors or eye movements.
  • Seizures.
  • Difficulty breathing.
  • Loss of consciousness.
  • Severe encephalopathy can result in coma.

How do you treat ANEC? ›

Treatment modalities are not well-established; empirical treatment with antibiotics and antiviral agents is the initial step, followed by steroids and immunoglobulin, as well as supportive care. Patients with ANEC have a variable prognosis, but mortality is very high.

How do you get acute encephalopathy? ›

What causes encephalopathy?
  1. An infection, either in your brain or coverings (encephalitis or meningitis), or in your body.
  2. A brain tumor.
  3. Pressure within your skull against your brain (intracranial pressure).
  4. A head injury.
  5. A stroke.
  6. Seizures, especially if untreated.
  7. A vitamin deficiency or malnutrition.

What is the most common cause of acute encephalitis syndrome? ›

Acute encephalitis is mostly caused by any of the many 'neurotrophic' viruses, many of which are vector-transmitted (arthropod-borne) arboviruses.

What causes necrotizing infection? ›

A very severe and usually deadly form of necrotizing soft tissue infection is due to the bacteria Streptococcus pyogenes, which is sometimes called "flesh-eating bacteria" or strep. Necrotizing soft tissue infection develops when the bacteria enters the body, usually through a minor cut or scrape.

What is the criteria for acute necrotizing encephalopathy? ›

[4] The proposed diagnostic criteria for ANEC include acute onset of encephalopathy with rapid neurological deterioration; CSF examination showing increased protein with no pleocytosis; neuroimaging showing bilateral symmetrical involvement of the thalamus, internal capsule, putamen, cerebellum, brainstem, and ...

Top Articles
Latest Posts
Recommended Articles
Article information

Author: Amb. Frankie Simonis

Last Updated:

Views: 5845

Rating: 4.6 / 5 (56 voted)

Reviews: 87% of readers found this page helpful

Author information

Name: Amb. Frankie Simonis

Birthday: 1998-02-19

Address: 64841 Delmar Isle, North Wiley, OR 74073

Phone: +17844167847676

Job: Forward IT Agent

Hobby: LARPing, Kitesurfing, Sewing, Digital arts, Sand art, Gardening, Dance

Introduction: My name is Amb. Frankie Simonis, I am a hilarious, enchanting, energetic, cooperative, innocent, cute, joyous person who loves writing and wants to share my knowledge and understanding with you.