Fazio–Londe disease
Rare childhood motor neuron disease of unknown genetic cause.
Fazio–Londe disease (FLD), also called progressive bulbar palsy of childhood, is a very rare inherited motor neuron disease of children and young adults. It is characterized by progressive paralysis of muscles innervated by cranial nerves. FLD, along with Brown–Vialetto–Van Laere syndrome (BVVL), are the two forms of infantile progressive bulbar palsy. However, unlike BVVL, the genetic cause of FLD remains unknown.
- Gene
- Unknown (no gene identified; SLC52A3, SLC52A2, and SLC52A1 are associated with Brown–Vialetto–Van Laere syndrome, not FLD)
- Chromosome locus
- Not confirmed (no gene has been identified for FLD)
Lore & Background
Fazio–Londe disease produces rapidly progressive weakness of tongue, face and pharyngeal muscles in a clinical pattern similar to myasthenia. Paralysis occurs secondary to degeneration of the motor neurons of the brain stem. The most frequent symptom at onset is unilateral facial paralysis, followed by dysarthria due to facial weakness or dysphagia. Both sexes can be affected.
The disease has no identified genetic cause; it is not linked to mutations in SLC52A3, SLC52A2, or SLC52A1, which are instead associated with Brown–Vialetto–Van Laere syndrome. Diagnosis is confirmed by muscle biopsy and clinical evaluation, but because the genetic basis is unknown, there is no established gene-based therapy. Riboflavin therapy, effective for BVVL, has not been shown to treat FLD.
Reader's Guide
Fazio–Londe disease is significant as a rare but treatable motor neuron disorder of childhood. Its recognition is critical because early intervention with high-dose riboflavin can alter the otherwise often fatal course. The disease highlights the importance of riboflavin transport in neurological function and the value of genetic testing for SLC52A genes. The condition is allelic and phenotypically similar to Brown–Vialetto–Van Laere syndrome, and its histologic alterations are identical to those seen in infantile-onset spinal muscular atrophy. The eponym honors Italian pathologist Eugenio Fazio and French physician Paul Frederic Louis Londe. Because treatment is inexpensive and low-risk, clinical guidelines recommend starting riboflavin therapy immediately upon suspicion, even before definitive genetic confirmation. This approach underscores a paradigm where rapid therapeutic intervention can prevent irreversible neurological damage in a rare disease setting.
Did You Know?
- Fazio–Londe disease is also called progressive bulbar palsy of childhood.
- Unlike Brown–Vialetto–Van Laere syndrome, Fazio–Londe disease has no identified gene and is not known to respond to riboflavin therapy.
- Postmortem examination has found depletion of nerve cells in the nuclei of cranial nerves, identical to infantile-onset spinal muscular atrophy.
More in Genetic disorders with OMIM but no gene 1-24
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