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

• BBGD (Biotin-Responsive Basal Ganglia Disease)
• Biotin-Responsive Basal Ganglia Disease (BBGD)

What is Biotin-Thiamine-Responsive Basal Ganglia Disease? (Definition/Background Information)

• Biotin-Thiamine-Responsive Basal Ganglia Disease is a rare condition that affects the brain and other parts of the nervous system. The severity of the condition and the associated signs and symptoms vary from person to person, even within the same family
• Biotin-Thiamine-Responsive Basal Ganglia Disease is caused by changes (mutations) in the SLC19A3 gene and is inherited in an autosomal recessive manner 
• Without early diagnosis and treatment, most affected people develop features of the condition between ages 3 and 10 years
• Signs and symptoms may include recurrent episodes of confusion, seizures, ataxia (problems coordinating movements), dystonia, facial palsy (weakness of the facial muscles), external ophthalmoplegia (paralysis of the muscles surrounding the eye), and dysphagia
• Eventually, these episodes can lead to coma or even death. Early and lifelong treatment with the vitamins biotin and thiamine may improve the symptoms

(Source: Biotin-Thiamine-Responsive Basal Ganglia Disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Biotin-Thiamine-Responsive Basal Ganglia Disease? (Age and Sex Distribution)

• Biotin-Thiamine-Responsive Basal Ganglia Disease is a rare congenital disorder. The presentation of symptoms may occur in childhood
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Biotin-Thiamine-Responsive Basal Ganglia Disease? (Predisposing Factors)

• A positive family history may be an important risk factor, since Biotin-Thiamine-Responsive Basal Ganglia Disease can be inherited
• Children born to consanguineous parents may bear an increased risk for developing the 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 Biotin-Thiamine-Responsive Basal Ganglia Disease? (Etiology)

• Biotin-Thiamine-Responsive Basal Ganglia Disease is an autosomal recessive genetic disorder
• Genetic mutations involving the SLC19A3 gene are reported to cause the disorder

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 Biotin-Thiamine-Responsive Basal Ganglia Disease?

The signs and symptoms of Biotin-Thiamine-Responsive Basal Ganglia Disease may include:

• Global developmental delay
• Abnormality of the basal ganglia
• Babinski sign
• Coma
• Confusion
• Craniofacial dystonia
• External ophthalmoplegia
• Fever
• Inability to walk
• Irritability
• Morphological abnormality of the pyramidal tract
• Muscular hypotonia of the trunk
• Mutism
• Paraparesis
• Ptosis
• Rigidity
• Seizures

(Source: Biotin-thiamine-responsive basal ganglia disease; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Biotin-Thiamine-Responsive Basal Ganglia Disease Diagnosed?

Biotin-Thiamine-Responsive Basal Ganglia 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 Biotin-Thiamine-Responsive Basal Ganglia Disease?

The complications of Biotin-Thiamine-Responsive Basal Ganglia Disease may include:

• Difficulty swallowing food
• Speech impediment
• Difficulties with movement
• Risk of falls and injury due to seizures

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

How is Biotin-Thiamine-Responsive Basal Ganglia Disease Treated?

• There is no cure for Biotin-Thiamine-Responsive Basal Ganglia Disease, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops
• Treatment with the vitamins biotin and thiamine may help reduce the severity of symptoms

How can Biotin-Thiamine-Responsive Basal Ganglia Disease be Prevented?

Biotin-Thiamine-Responsive Basal Ganglia 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 Biotin-Thiamine-Responsive Basal Ganglia Disease? (Outcomes/Resolutions) 

• The prognosis of Biotin-Thiamine-Responsive Basal Ganglia Disease is dependent upon the severity of the signs and symptoms and associated complications, if any
• With an early diagnosis and sustained treatment with vitamins biotin and thiamine, an affected individual may prevent severe symptoms from occurring
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Biotin-Thiamine-Responsive Basal Ganglia Disease:

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

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