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

• Late Adult-Onset Distal Myopathy Type 2
• Zaspopathy
• ZASP-Related Myofibrillar Myopathy

What is Late-Onset Distal Myopathy, Markesbery-Griggs type? (Definition/Background Information)

• Late-onset Distal Myopathy, Markesbery-Griggs Type, is an inherited muscle disorder characterized by progressive wasting and consequent weakness of distal muscles (hands and legs)
• The condition is caused by mutation(s) in ZASP gene, and is inherited in an autosomal dominant manner
• The manifestation of symptoms begins in adult life, typically after the age of 35

Who gets Late-Onset Distal Myopathy, Markesbery-Griggs type? (Age and Sex Distribution)

• Late-Onset Distal Myopathy, Markesbery-Griggs type is a rare disorder
• The presentation of symptoms is usually onset in adulthood, after the age of 35 years
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Late-Onset Distal Myopathy, Markesbery-Griggs type? (Predisposing Factors)

• A positive family history may be an important risk factor, since Late-Onset Distal Myopathy, Markesbery-Griggs type can be inherited

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 Late-Onset Distal Myopathy, Markesbery-Griggs type? (Etiology)

Late-Onset Distal Myopathy, Markesbery-Griggs type is caused by mutation(s) in the ZASP gene.

• This gene codes for the Z-disc-associated, alternatively spliced, PDZ motif-containing protein
• The mutations cause disruptions in the actin filaments in skeletal muscle, causing symptoms of myofibrillar myopathy in Late-Onset Distal Myopathy, Markesbery-Griggs type
• The disorder is inherited in an autosomal dominant manner

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly function gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring

What are the Signs and Symptoms of Late-Onset Distal Myopathy, Markesbery-Griggs type?

The signs and symptoms of Late-Onset Distal Myopathy, Markesbery-Griggs type, may include:

• Weakness in hands and feet, progressing to weakness in arms and legs
• Foot drop, where one is unable to lift the toes while walking

How is Late-Onset Distal Myopathy, Markesbery-Griggs type Diagnosed?

Late-Onset Distal Myopathy, Markesbery-Griggs type 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 Late-Onset Distal Myopathy, Markesbery-Griggs type?

The complications of Late-Onset Distal Myopathy, Markesbery-Griggs type may include:

• Unnatural gait
• Progressive muscle weakness causing problems with walking
• Limitations on strenuous physical activity 
• Negative effects on proximal muscle groups

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

How is Late-Onset Distal Myopathy, Markesbery-Griggs type Treated?

There is no cure for Late-Onset Distal Myopathy, Markesbery-Griggs type, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that may develop.

The treatment options may include:

• Physiotherapy to improve muscle strength
• Use of leg braces to improve mobility
• Use of wheel chair for mobility

How can Late-Onset Distal Myopathy, Markesbery-Griggs type be Prevented?

Late-Onset Distal Myopathy, Markesbery-Griggs type 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 Late-Onset Distal Myopathy, Markesbery-Griggs type? (Outcomes/Resolutions)

• The prognosis of Late-Onset Distal Myopathy, Markesbery-Griggs type 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 Late-Onset Distal Myopathy, Markesbery-Griggs type:

• Late-Onset Distal Myopathy, Markesbery-Griggs type is also known by the following names: ZASP-Related Myofibrillar Myopathy

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

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