Roussy-Levy syndrome is a hereditary disease from the group of motor sensory neuropathies, which according to some ideas is a phenotypic variant of Charcot—Marie-Tut amyotrophy. The main symptoms include sensitive ataxia, weakness and hypotrophy of the muscles of the distal extremities (mainly the lower ones), tendon areflexia. When establishing a diagnosis, they rely on the features of the clinical symptom complex and the course of the disease, family history, and the results of electroneuromyography. Patients are shown regular symptomatic treatment: anticholinesterase pharmaceuticals, vitamins, potassium, ATP, massage, physiotherapy, exercise therapy.
Roussy-Levy syndrome has an eponymous name in honor of the French doctors neurologist Levy and pathologist Roussy who described it in 1926. The authors designated the described syndrome as familial areflex distasia with slow progression. The basic clinical manifestations of the syndrome are ataxia and tendon areflexia, which formed the basis of its other name – “ataxia-areflexia syndrome”. According to the international classification of the 10th revision, the Roussy-Levy syndrome is classified as a group of hereditary motor sensory neuropathies (NMSN). However, there is no clear opinion among clinicians on how to classify this pathology. According to the symptoms, a number of neurologists attribute the Roussy-Levy syndrome to a clinical form that occupies an intermediate position between Charcot-Marie-Toute disease and Friedreich’s ataxia, other authors consider it a separate clinical variant of spinal amyotrophy. Despite the genetic evidence obtained for the latter statement, many neurologists still distinguish the Roussy-Levy syndrome as a separate nosology.
The family nature of the disease indicates its hereditary genesis. Previously, it was found that Roussi-Levy neuropathy occurs in families with repeated cases of Charcot-Marie-Toute disease. Molecular genetic studies in recent years have revealed that the genetic substrate of the syndrome is disorders in the 17th chromosome (locus 17p11.2) in the form of the presence of duplicates of individual genes, point mutations of the MPZ — zero myelin protein gene. This discovery allows us to consider the Roussy-Levy syndrome as a phenotypic form of Charcot-Marie-Toute neural amyotrophy (NMHS variant IA).
The inheritance of the syndrome is carried out in an autosomal dominant way. Morphologically, degenerative changes in the posterior spinal roots and peripheral nerve trunks are determined in the form of moderate demyelination and a decrease in the number of nerve fibers; dystrophic changes in the pyramidal and cerebellar tracts passing in the lateral columns of the spinal cord; degeneration of the posterior columns; atrophy of skeletal muscle fibers.
The onset of symptoms usually occurs in childhood, sometimes puberty, in some cases it is possible in adults. The initial complaint is awkwardness when walking due to a decrease in the strength of the muscles of the lower leg (mostly of the peroneal group) and sensitive ataxia. Muscle weakness causes difficult back flexion of the feet, their drooping in a state of plantar flexion. An early sign of the disease is the loss of tendon reflexes of the lower extremities (knee, achilles). Over time, there is areflexia of the upper extremities, weakness of the muscles of the distal parts of the hands and atrophy of the muscles of the hand. There are polyneuritic disorders of sensitivity: pain and temperature hypesthesia in the form of “socks” and “gloves”, disorder of deep types (musculoskeletal, vibrational perception). The latter causes the existence of sensitive ataxia.
In the appearance of the patient, attention is drawn to the hypotrophy of the muscles of the lower legs, the so-called “stork legs”. The severity of gait disorders is variable: from slight awkwardness to a typical steppage with a high rise of the leg bent at the knee and the foot hanging down. Ataxia rarely reaches a rough expression, is characterized by instability when walking, general awkwardness, disproportionality and asymmetry of precise movements. There is shakiness in the Romberg pose, overshooting and tremor when performing coordination tests. A hollow foot is characteristic, which differs from Fredreich’s foot by a combination with arachnodactyly, the location of the fingers in the form of a trident or bicuspid, deformities of the fingers. Typically, the disappearance of the high arch of the foot when leaning on it while walking. Along with the deformation of the feet, there is a similar deformation of the hands. Many patients have deformities of the chest, curvature of the spine by the type of kyphoscoliosis and other markers of connective tissue dysplasia (hypertelorism, enlarged bridge of the nose, hydrocephalic skull, Gothic palate).
The diagnosis is based on the clinical picture of the disease and its change in dynamics. From neural amyotrophy, Roussi-Levy neuropathy is distinguished by a lower severity of muscular hypotrophy, from Friedreich’s disease — the absence of dysarthria and a tendency to stabilize the condition. Differential diagnosis is also carried out with other types of polyneuropathies, with myopathy and myotonia, amyotrophic lateral sclerosis, Refsum disease, myelopathies. Patients are advised to consult a geneticist and genealogical analysis.
In order to clarify the diagnosis, the neurologist prescribes electroneuromyography, the results of which indicate a slowdown in the conduction of impulses along the nerve trunks. In complex diagnostic cases, a biopsy of the muscles and/or superficial nerves of the lower extremities is performed. Microscopic examination of muscle tissue reveals atrophic changes in individual bundles of muscle fibers. Microscopy of nerve preparations determines the proliferation of elements of the Schwann shell, leading to hypertrophy of nerve fibers, in its shape resembling an onion.
Treatment and prognosis
Currently, only symptomatic therapy based on pharmaceuticals that facilitate the conduction of a nerve impulse and improve the metabolic processes of nervous tissue has been developed. The components of treatment are usually thiamine, pyridoxine, vitamin C, cyanocobalamin, potassium orotate, anticholinesterase agents (ambenonium chloride, distigmine, galantamine, pyridostigmine, neostigmine), ATP. In parallel, physical therapy classes, massage, physiotherapy and segmental reflex therapy are recommended. Deformity of the feet is an indication for consultation with an orthopedist with the selection of orthopedic shoes.
Roussy-Levy syndrome has a good prognosis for life. The slow increase in symptoms, followed by stabilization of the process, provides most patients with long-term preservation of working capacity and a slight decrease in it. In some cases, there is a steady progression of muscle weakness and hypotrophy, leading to difficulty walking independently.