What is Brown-Vialetto-Van Laere syndrome?

BVVL is a rare, progressive, neurodegenerative motor neuron disorder that specifically includes palsies (paralysis) of the cranial nerves, and is sometimes referred to as “bulbar palsy.”  The name Brown-Vialetto-Van Laere comes from physicians and researchers who described some of the first reported cases (Brown, 1894; Vialetto, 1936; and Van Laere, 1966), all of which also include sensorineural hearing loss. Though sensorineural hearing loss is a primary component of the syndrome, it may not be discovered until late in children due to the mildness of the hearing loss or the more obvious symptoms that manifest first. Progressive bulbar palsy without hearing loss is referred to as Fazio-Londe syndrome.

Onset of symptoms varies from infancy to the third decade.  In many cases, children lead a normal life developmentally, disease-free, for years before developing symptoms.  Typically, the first symptom is sensorineural deafness. Other examples of nerve degeneration include vocal cord paralysis, ptosis (droopy eyelids), facial weakness, slurred speech, dysphagia (difficulty swallowing), visual difficulty secondary to optic atrophy, neck and shoulder weakness, limb weakness, autonomic dysfunction, and respiratory compromise.

The course of the disease is variable as some affected individuals gradually get worse while others may have plateaus of stable disease throughout their course; however, all cases reported are fatal, and only one-third of all individuals affected with Brown-Vialetto-Van Laere have survived for longer than ten years.

What is the cause of BVVL?

As of March 4, 2010, at least one gene has been linked as the cause of BVVL, as an autosomal recessive pattern of inheritance. The remaining cases that have yet to be linked to this gene are being further investigated for hopeful future genetic findings.

How common is BVVL?

Throughout the past century, only 59 cases of Brown-Vialetto-Van Laere have been reported in the literature; however, as we continue to have families and/or their physicians contact us through this web site, we are learning that BVVL is not near as rare as the literature purports. Unfortunately, only one of the more than a dozen cases that we have come across in one year's span has been reported, and BVVL International has been able to garner much from these unreported cases, far surpassing the information that is available from the literature.

How is BVVL diagnosed?

Clinical presentation of hearing loss, other cranial nerve palsies, and lower motor neuron limb involvement raises the possibility of BVVL.  However, it is important to be evaluated by a pediatric neurologist who can also test for treatable metabolic conditions which may present similarly.  It is also important to seek a second opinion.

Hearing tests show sensorineural hearing loss, and brainstem auditory evoked potentials (BAER) are abnormal.  Magnetic resonance imaging (MRI) of the brain may show hyperintensities, especially in the brainstem, or may show nothing at all.  Muscle biopsy results are typically normal or show groups of atrophic fibers suggesting denervation of muscles.  Neurophysiologic tests such as EMG and nerve conduction studies also confirm denervation of muscles, both chronic and active.  Cerebral spinal fluid (CSF) analysis after lumbar puncture is typical normal or only shows mildly elevated protein.

Although BVVL shares similar features with a family of diseases known as spinal muscular atrophy (SMA), affected individuals that have been tested and reported in the literature were negative for SMA gene mutations.

To date, there is at least one genetic test available to confirm the presence of BVVL.
 
Is there treatment?

There is no certain effective treatment for Brown-Vialetto-Van Laere.  In some case reports, steroids and intravenous immunoglobulins (IVIg) have been tried with little success, typically short periods of stabilization before disease progression.

Supportive care and symptomatic treatment such as tracheostomy, assisted ventilation, and gastrostomy are typically offered to patients and their families.

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