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

• Glycogen Storage Disease XI
• Lactate Dehydrogenase Deficiency Disorder Type A

What is Lactate Dehydrogenase A Deficiency Disorder? (Definition/Background information)

• Lactate Dehydrogenase A Deficiency Disorder is a condition that affects how the body breaks down sugar to use as energy in muscle cells
• People with this condition experience fatigue, muscle pain, and cramps during exercise (exercise intolerance)
• In some people, high-intensity exercise or other strenuous activity leads to the breakdown of muscle tissue (rhabdomyolysis), which can lead to myoglobinuria (rust-colored urine indicating breakdown of muscle tissue) and kidney damage. A skin rash may also develop
• The severity of the signs and symptoms varies greatly among affected individuals
• Lactate Dehydrogenase A Deficiency Disorder is caused by mutations in the LDHA gene. This condition is inherited in an autosomal recessive pattern

(Source: Lactate Dehydrogenase A Deficiency Disorder; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Lactate Dehydrogenase A Deficiency Disorder? (Age and Sex Distribution)

• Lactate Dehydrogenase A Deficiency Disorder is a rare congenital disorder, affecting 1 in a million individuals in Japan. There are no data available for other countries
• The presentation of symptoms may occur at any age when an individual is active
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Lactate Dehydrogenase A Deficiency Disorder? (Predisposing Factors)

• A positive family history may be an important risk factor, since Lactate Dehydrogenase A Deficiency Disorder can be inherited
• Currently, no other risk factors have been clearly identified for this deficiency disorder

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 Lactate Dehydrogenase A Deficiency Disorder? (Etiology)

• Lactate Dehydrogenase A Deficiency Disorder is caused by mutation(s) in the LDHA gene, which codes for the “A” subunit of lactose dehydrogenase enzyme
• The condition is inherited in an autosomal recessive manner

Autosomal recessive inheritance: 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 Lactate Dehydrogenase A Deficiency Disorder?

The signs and symptoms of Lactate Dehydrogenase A Deficiency Disorder may vary among the affected individuals and it may include the following:

• Muscle pain
• Fatigue
• Rashes
• Cramps during intense physical activity
• Red or brown urine due to rhabdomyolysis (breakdown of muscle tissue) as a result of high intensity physical exercise

How is Lactate Dehydrogenase A Deficiency Disorder Diagnosed?

Lactate Dehydrogenase A Deficiency Disorder 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
• Molecular genetic testing to check for or confirm causative gene mutation(s)

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 Lactate Dehydrogenase A Deficiency Disorder?

The complications of Lactate Dehydrogenase A Deficiency Disorder may include:

• Damage to kidneys due to excess release of myoglobin from muscles
• Kidney failure

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

How is Lactate Dehydrogenase A Deficiency Disorder Treated?

• There is no cure for Lactate Dehydrogenase A Deficiency Disorder, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develop
• Affected individuals may benefit from identifying triggers of rhabdomyolysis and avoid them, to minimize episodes of muscle tissue damage

How can Lactate Dehydrogenase A Deficiency Disorder be Prevented?

Currently, Lactate Dehydrogenase A Deficiency Disorder 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), if available, 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 Lactate Dehydrogenase A Deficiency Disorder? (Outcomes/Resolutions)

• The prognosis of Lactate Dehydrogenase A Deficiency Disorder 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 Lactate Dehydrogenase A Deficiency Disorder:

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

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