Summary about Disease
Riboflavin Transporter Deficiency (RTD), also known as Brown-Vialetto-Van Laere Syndrome (BVVLS) and Fazio-Londe disease with auditory neuropathy, is a rare, progressive neurological disorder affecting motor neurons and sensory nerves. It is caused by mutations in genes (SLC52A1, SLC52A2, and SLC52A3) responsible for transporting riboflavin (vitamin B2) into cells. This deficiency leads to impaired cellular energy production, affecting various bodily systems, particularly the nervous system. The condition primarily affects children and young adults.
Symptoms
Symptoms of RTD are highly variable and can include:
Progressive muscle weakness (especially in the face, neck, and limbs)
Bulbar palsy (difficulty swallowing, speaking, and breathing)
Hearing loss (often sensorineural)
Optic atrophy (leading to vision loss)
Sensory neuropathy (numbness, tingling, and pain)
Respiratory difficulties
Seizures
Ataxia (lack of coordination)
Causes
RTD is caused by autosomal recessive mutations in the SLC52A1, *SLC52A2*, or *SLC52A3* genes. These genes encode riboflavin transporters RFVT1, RFVT2, and RFVT3 respectively, which are responsible for intestinal absorption and cellular uptake of riboflavin. Individuals must inherit a mutated copy of the gene from both parents to develop the condition. Mutations in any of these genes disrupt the normal transport of riboflavin into cells, leading to the observed symptoms.
Medicine Used
The primary treatment for RTD involves high-dose oral riboflavin supplementation. The dosage is individualized based on the patient's response and tolerance. Other supportive therapies may include:
Physical therapy (to maintain muscle strength and mobility)
Occupational therapy (to assist with daily living activities)
Speech therapy (to address swallowing and speech difficulties)
Respiratory support (ventilator)
Is Communicable
No, Riboflavin Transporter Deficiency is not communicable. It is a genetic disorder caused by gene mutations and cannot be transmitted from person to person.
Precautions
Since RTD is a genetic condition, precautions mainly involve genetic counseling for families with a history of the disorder. This can help assess the risk of having affected children. Early diagnosis and prompt treatment with riboflavin supplementation can help manage symptoms and slow disease progression. Individuals with RTD require ongoing monitoring and supportive care to address their specific needs.
How long does an outbreak last?
RTD is not an infectious disease, so the term "outbreak" does not apply. It is a chronic, progressive condition that lasts throughout the affected individual's lifetime.
How is it diagnosed?
Diagnosis of RTD typically involves:
Clinical evaluation (assessing symptoms and neurological examination)
Genetic testing (to identify mutations in the SLC52A1, SLC52A2, or *SLC52A3* genes)
Blood tests (to measure riboflavin levels)
Nerve conduction studies and electromyography (EMG) (to assess nerve and muscle function)
Brain and spinal cord imaging (MRI) (to rule out other conditions)
Audiological testing (to evaluate hearing loss)
Timeline of Symptoms
The onset and progression of symptoms vary greatly among individuals with RTD. Some may present with symptoms in infancy or early childhood, while others may not develop symptoms until adulthood. The rate of progression is also variable, with some experiencing a rapid decline while others have a slower, more gradual course.
Early Onset : Infancy, Childhood, Adulthood
Important Considerations
Early diagnosis and treatment with riboflavin are crucial to improving outcomes.
RTD is a progressive condition, and ongoing monitoring and supportive care are essential.
Genetic counseling is recommended for families with a history of the disorder.
Due to the rarity of the condition, patients should be managed by physicians with experience in treating neuromuscular disorders.
Research is ongoing to better understand the disease and develop new therapies.