What are the other Names for this Condition? (Also known as/Synonyms)

• APBD (Adult Polyglucosan Body Disease)
• Polyglucosan Body Disease, Adult Form

What is Adult Polyglucosan Body Disease? (Definition/Background Information)

• Adult Polyglucosan Body Disease (APBD) affects the nervous system. Individuals with this condition usually begin to show signs of the disorder after the age of 40
• Signs and symptoms include trouble walking due to decreased sensation in the legs (peripheral neuropathy) and muscle weakness and stiffness (spasticity). Individuals may also have trouble controlling bladder function as a result of damage to the nerves of the bladder (neurogenic bladder)
• Approximately half of the individuals with Adult Polyglucosan Body Disease also experience some degree of intellectual impairment
• Mutations in the GBE1 gene can cause Adult Polyglucosan Body Disease. In some cases, no mutation can be found and the cause of the disease is not known
• Adult Polyglucosan Body Disease is thought to be inherited in an autosomal recessive manner
• Treatment usually involves a team of specialists who can address the specific symptoms such as walking difficulties, incontinence, and intellectual impairment

(Source: Adult Polyglucosan Body Disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Adult Polyglucosan Body Disease? (Age and Sex Distribution)

• Adult Polyglucosan Body Disease is a rare disorder. The presentation of symptoms occur at middle-age
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Adult Polyglucosan Body Disease? (Predisposing Factors)

• A positive family history may be an important risk factor, since Adult Polyglucosan Body Disease can be an inherited condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Adult Polyglucosan Body Disease? (Etiology)

• Mutations in the GBE1 gene can cause Adult Polyglucosan Body Disease. In some cases, no mutation can be found and the cause of the disease is not known
• Adult Polyglucosan Body Disease is thought to be inherited in an autosomal recessive manner

(Source: Adult Polyglucosan Body Disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Adult Polyglucosan Body Disease?

The signs and symptoms of Adult Polyglucosan Body Disease may include:

• Abnormal upper motor neuron morphology
• Abnormality of metabolism/homeostasis
• Abnormality of the cerebral white matter
• Cognitive impairment
• Paresthesia; tingling sensation on the hands or feet
• Tetraparesis; when the arms and legs are paralyzed

Very frequently present symptoms in 80-99% of the cases:

• Abnormal pyramidal signs
• Gait disturbance 
• Hemiparesis; paralysis of one part of the body
• Intellectual disability
• Neurogenic bladder; bladder dysfunction due to neurological defects
• Spasticity or stiff muscles
• Urinary incontinence

Frequently present symptoms in 30-79% of the cases:

• Behavioral abnormality
• Distal sensory impairment
• Skin ulcer

Occasionally present symptoms in 5-29% of the cases:

• Abnormality of extrapyramidal motor function
• Ataxia; when one is unable to control the movement of muscles
• Dementia
• EMG abnormality
• Limitation of joint mobility

(Source: Adult Polyglucosan Body Disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Adult Polyglucosan Body Disease Diagnosed?

Adult Polyglucosan Body Disease is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the Possible Complications of Adult Polyglucosan Body Disease?

The complications of Adult Polyglucosan Body Disease may include:

• Severe neurological defects
• Severe intellectual deficit
• Paralysis of the body

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Adult Polyglucosan Body Disease Treated?

• Treatment usually involves a team of specialists who can address the specific symptoms such as walking difficulties, incontinence, and intellectual impairment

(Source: Adult Polyglucosan Body Disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Adult Polyglucosan Body Disease be Prevented?

Currently, Adult Polyglucosan Body Disease may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of Adult Polyglucosan Body Disease? (Outcomes/Resolutions)

• The prognosis of Adult Polyglucosan Body Disease is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Adult Polyglucosan Body Disease:

The following DoveMed website link is a useful resource for additional information:

https://www.dovemed.com/diseases-conditions/rare-disorders/