Adult Polyglucosan Body Disease (APBD)

Description

Adult Polyglucosan Body Disease (APBD) is a rare, progressive neurological disorder that affects the nervous system. It is caused by a buildup of abnormal glycogen-like material, known as polyglucosan bodies, within nerve cells. This buildup disrupts the normal functioning of these cells, leading to a range of neurological symptoms. This article will delve into the details of APBD, covering its causes, inheritance patterns, diagnosis, management strategies, and how individuals can thrive with this condition.

Genes Involved

APBD is caused by mutations in the GBE1 gene, which provides instructions for making the enzyme glycogen branching enzyme. This enzyme is crucial for the breakdown and storage of glycogen, a complex carbohydrate used as energy by the body. Mutations in GBE1 lead to a deficiency of this enzyme, resulting in the buildup of polyglucosan bodies within nerve cells.

Recognizing the Signs and Symptoms

APBD typically presents with progressive weakness, particularly in the legs and arms. Other common symptoms include:

Difficulty walking and balance problems
Stiffness in the limbs
Muscle cramps
Fatigue
Cognitive impairment, including memory problems and difficulty concentrating
Speech difficulties
Vision problems
Bowel and bladder dysfunction

The severity and progression of symptoms can vary widely among individuals with APBD.

Causes

APBD is caused by a genetic mutation in the GBE1 gene. This mutation is inherited in an autosomal recessive pattern, meaning that an individual must inherit two copies of the mutated gene, one from each parent, to develop the condition. If only one copy of the mutated gene is inherited, the individual is a carrier and does not exhibit symptoms.

Inheritance/recurrence risk

Inheritance or Recurrence Risk

APBD is inherited in an autosomal recessive pattern. This means that both parents must be carriers of the mutated gene for their child to inherit the condition. If both parents are carriers, there is a 25% chance that their child will inherit two copies of the mutated gene and develop APBD. There is a 50% chance that their child will inherit one copy of the mutated gene and be a carrier, and a 25% chance that their child will inherit two copies of the normal gene and not be affected by the condition.

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