Brachial amyotrophic diplegia, also called Vulpian-Bernhardt Syndrome (VBS), flail arm syndrome, or man-in-barrel syndrome, is a rare

motor neuron disease Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or—in the United States—Lou Gehrig's disease (LGD), is a rare, terminal neurodegenerative disorder that results in the progressive loss of both upper and low ...

, often considered to be a phenotype or regional variant of

amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or—in the United States—Lou Gehrig's disease (LGD), is a rare, Terminal illness, terminal neurodegenerative disease, neurodegenerative disorder that results i ...

. In the first twelve to eighteen months, only a progressive weakness of one or both arms is observed. Within the spectrum of ALS, this subtype has a relatively longer survival time. Because of its distinct symptoms, it was suggested that VBS is a separate entity, different from ALS.

History

The disease was described first in 1886 by the French neurologist

Alfred Vulpian Edmé Félix Alfred Vulpian (5 January 1826 – 18 May 1887) was a French physician and neurologist. He was the co-discoverer of Vulpian-Bernhardt spinal muscular atrophy and the Vulpian-Heidenhain-Sherrington phenomenon. Vulpian was born in Pa ...

and the German neuropathologist

Martin Bernhardt Martin Bernhardt (10 April 1844 – 17 March 1915) was a German neuropathologist. Bernhardt was a native of Potsdam. His family was Jewish.Andreas Killen, ''Berlin Electropolis: Shock, Nerves, and German Modernity'', University of California Pr ...

as a progressive weakness of the upper limbs but bulbar muscles unaffected. It is a rare and atypical disease that can only be diagnosed after a significant time has elapsed. A 2015 study found significant differences between ALS and VBS, most importantly the absence of signs of

upper motor neuron Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles ...

compromise in patients with VBS. The study suggested that VBS is a different entity from ALS.

Pathophysiology

While the cause is usually unknown, it can arise as a

paraneoplastic syndrome A paraneoplastic syndrome is a syndrome (a set of signs and symptoms) that is the consequence of a tumor in the body (usually a cancerous one). It is specifically due to the production of chemical signaling molecules (such as hormones or cytokin ...

. There have been case reports linking the condition to

SOD1 Superoxide dismutase u-Zn'' also known as superoxide dismutase 1 or hSod1 is an enzyme that in humans is encoded by the ''SOD1'' gene, located on chromosome 21. SOD1 is one of three human superoxide dismutases. It is implicated in apoptosis, fami ...

mutations.

Symptoms

A study of 1,188 ALS cases in London between 1993 and 2007, and 432 in Melbourne, classified cases as ''flail arm syndrome'' when in the first 12 months only a weakness of upper limbs was reported. Based on this criterium, 135 cases or 11% were classified as ''flail arm syndrome''. At later stages, weakening of lower limbs and other ALS symptoms were observed. 16 per cent of these flail arm syndrome cases survived more than ten years, the highest of all variants of ALS in the study.

Cases

One of the few people with brachial amyotrophic diplegia who has spoken in public about the disease is Sonia Bustamante Dominguez, a Mexican woman who showed the first symptoms in 2012 and was diagnosed in 2016. In 2024 she described her body as a jail.

References

{{Authority control Motor neuron diseases Neurodegenerative disorders Neurological disorders