What is Roussy Levy Syndrome?
Roussy Levy syndrome is a congenital disease. Roussy Levy syndrome leads to disruption of signals between Schwann cells and neurons which are very much essential for survival and differentiation of the nerve cell. Let us look at the causes, symptoms, diagnosis and treatment of Roussy Levy syndrome.
Neurons are the basic components of nervous system. They are produced at a faster rate in infants and by the age of 5 years, maximum number of neurons required for life time is produced. It is still a topic of discussion whether they have the ability of dividing during brain damages or not. It is important to know the structure of neuron.
A neuron is composed of a cell body which contains a nucleus, cytoplasm, Nissl granules, dendrites; a long extension called axon which is protected by myelin sheath. This sheath is made up of fats and proteins. Myelin sheath covers the axon and apart from protecting it, the sheath also increases the speed of electrical signals. In the central nervous system, myelin sheath is produced by oligodendrocytes whereas in peripheral nervous system, it is produced by Schwann cells. Myelin sheath does not run continuously along the length of axon. It covers the axon by long multiple sections and these sections have short gaps in between. Myelin sheath reduces the axonal membrane capacitance. It is very important to the nervous system as it helps in cognition, motor and sensory functions.
Roussy Levy syndrome is also known by other names:
- Roussy Levy hereditary areflexic dystasia
- Hereditary areflexic dystasia
- Charcot-Marie Tooth disease
- Hereditary Motor Sensory Neuropathy
Causes for Roussy Levy Syndrome
Roussy Levy syndrome is categorized under genetic diseases as it is passed on to the next generation from parents. The symptoms are exhibited because of problem in nerve conduction and dysfunction of sensory neurons. The causes of Roussy Levy syndrome revolve around genetic changes.
PMP 22 gene and MPZ gene are the two main genes in humans which code for producing Peripheral Myelin Protein 22 (PMP22) and Myelin Protein Zero (MPZ) respectively. PMP22 is a vital component of myelin sheath and MPZ is an important component of peripheral myelin. Mutation caused in these two main genes is the main cause for Roussy Levy syndrome. In PMP22 gene, mutation occurs by duplication of the same gene. In MPZ, mutation occurred is called as missense mutation which is a result of change in a single nucleotide in a codon and hence codes for a different amino acid. Mutation in PMP22 gene is also referred to as Charcot Marie Tooth disease type 1A and mutation in MPZ gene is referred to as Charcot Marie Tooth disease type 1B. Studies have shown that this condition is a variant of Charcot Marie Tooth disease type 1A related to duplication of chromosome 17p11.2.1
Symptoms of Roussy Levy Syndrome
The symptoms of Roussy Levy syndrome are mostly observed in infancy and progress slowly. The symptoms of Roussy Levy syndrome are a result of neuropathies that damage the peripheral nerves.2
Some of the most important signs and symptoms of Roussy Levy syndrome include:
- Muscle wasting
- Decreased response of muscles for galvanic and faradic stimulation
- Lack of voluntary coordination of muscles
- Problems in producing words
- Abnormal eye movements
- The sole of the foot becomes hollow on bearing weight (pes cavus)
- Tremors of upper limbs including postural and static types
- Under-ventilation of lungs
- Abnormal curvature of spinal cord
- Dropping of the forefoot
- Inability to walk properly
- Loss of balance of the body
Is Roussy Levy Syndrome Inherited?
Only one copy of the defected gene is enough to express the disease. To explain, let us suppose a couple with affected male and an unaffected female. If they have two children, one child may receive the defected gene from the father and get affected by the disease. The other child might not inherit the defected gene from the father neither be affected nor be the carriers. Here, the gender of the children to get affected would remain insignificant since this is not linked with sex chromosomes.
Diagnosis of Roussy Levy Syndrome
Diagnosis of Roussy Levy syndrome depends on genetic testing. In case of Roussy Levy syndrome, probably one type of genetic testing would not help in detecting the disease as it is caused by mutations in MPZ or PMP22 genes which are responsible for causing other gene related disorders. Hence it is desired to go for more than one type of genetic tests which would help to diagnose the disease.
Treatment for Roussy Levy Syndrome
The treatment for Roussy Levy syndrome is currently not available. This may be due to lack of published documents or due to lack of research done on this. Many cases of Roussy Levy syndrome are treated for signs and symptoms. Since this syndrome resembles Charcot Marie Tooth disease, treatment may also resemble with the treatment of the same disease. Some of the treatments which would relieve the ailments of Roussy Levy syndrome such as pain, physical stress and mental stress would be as follows:
- Drugs like beta blockers to reduce the stress on heart
- Corrective surgery for high arches of the sole
- Special footwear to attend the problem of foot drop
- Crutches to aid in walking
- Antiseizure drugs
- Drugs to reduce neuropathic pain
- Specific exercises
- Genetic counseling with the patients and family members
Prognosis of Roussy Levy Syndrome
The individuals have normal life expectancy because Roussy Levy syndrome is not a fatal one. This does not mean that the individuals with Roussy Levy syndrome can lead a normal life; instead, they need orthopedic supporting equipment like crutches or wheelchair since the muscle wasting would be progressive.
Neurons are the structural and functional unit of nervous system. They are the longest cells in the human body which is thought to produce only till 5 years of age in one’s life span. Hence it is very important to protect them and avoid them from damages.
Roussy Levy Syndrome is a rare genetic neuromuscular disorder. It is characterized by loss of communication between the muscles and the peripheral nerves in this disorder. Roussy Levy syndrome can be caused in individuals with only one copy of defected gene. Hence it is treated as the autosomal dominant disorder. This condition is also referred to as denervation which is the main cause for the expressions of signs and symptoms of Roussy Levy syndrome. Genetic counseling with the individuals having family history would be more helpful.