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

• Lactate Dehydrogenase B Deficiency Syndrome
• Lactate Dehydrogenase Deficiency Disorder Type B
• LDH Deficiency Disorder B

What is Lactate Dehydrogenase B Deficiency Disorder? (Definition/Background Information)

• Lactate Dehydrogenase B Deficiency Disorder (LDHBD Disorder) is a condition that affects how the body breaks down sugar to use as energy in muscle cells
• Unlike people with lactate dehydrogenase A deficiency, people with this condition typically do not have any signs or symptoms. It is unclear why this condition does not cause any health problems
• Affected people are usually diagnosed when routine blood tests reveal reduced activity of the enzyme lactate dehydrogenase
• Lactate Dehydrogenase B Deficiency Disorder is caused by mutations in the LDHB gene and is inherited in an autosomal recessive manner

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

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

• Lactate Dehydrogenase B Deficiency Syndrome is a rare congenital disorder
• This condition does not lead to clinically significant signs and symptoms
• This condition may be present in both genders in individuals of all races and ethnicities around the world 

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

• A positive family history may be an important risk factor, since Lactate Dehydrogenase B Deficiency Syndrome can be inherited
• Currently, no other risk factors have been clearly identified for the 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 B Deficiency Disorder? (Etiology)

• Lactate Dehydrogenase B Deficiency Disorder is caused by mutations in the LDHB gene
• This gene codes for the “B” subunit of the lactate dehydrogenase enzyme
• The condition is inherited in an autosomal recessive manner

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 Lactate Dehydrogenase B Deficiency Disorder?

• No clinically significant signs and symptoms are reported for Lactate Dehydrogenase B Deficiency Disorder
• Low levels of B subunit of the lactate dehydrogenase enzyme showing decreased activity is noted

How is Lactate Dehydrogenase B Deficiency Disorder Diagnosed?

• Lactate Dehydrogenase B Deficiency Disorder (LDHBD Disorder) is typically diagnosed after routine blood tests show reduced lactate dehydrogenase (LDH) activity in serum and/or red blood cells
• A person has LDHBD when more specific testing shows absent or decreased levels of the LDH sub-unit H(B). This means that people with LDHBD Disorder may have either complete absence of this sub-unit, or a marked deficiency of the sub-unit

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

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 B Deficiency Disorder?

Lactate Dehydrogenase B Deficiency Disorder is not reported to cause significant clinical signs and symptoms, and there are no known complications.

How is Lactate Dehydrogenase B Deficiency Disorder Treated?

Since individuals with Lactate Dehydrogenase B Deficiency Disorder do not exhibit any significant signs and symptoms, no health problems are generally reported, and therefore, no treatment is deemed necessary.

How can Lactate Dehydrogenase B Deficiency Disorder be Prevented?

Currently, Lactate Dehydrogenase B Deficiency Disorder may not be preventable, since it is a genetic disorder.

• However, genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in a better understanding of the risks of having a child with the disorder 
• 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 B Deficiency Disorder? (Outcomes/Resolutions)

The prognosis of Lactate Dehydrogenase B Deficiency Syndrome is good, since the condition does not result in any adverse health problem.

Additional and Relevant Useful Information for Lactate Dehydrogenase B Deficiency Disorder:

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

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