“adeno-associated virus” is a small single strand DNA virus. It belongs to the family of the Parvoviridae and in the genus Dependovirus. The viral particle is composed of one positive or negative polarity strand of DNA in a capsid. The mean size of an AAV particle is 18 to 22 nm. AAVs are the only non-autonomous parvoviruses. When we speak of “rAAV”, this means the recombinant AAV virus, i.e. modified to become a vector (and thus is no longer infectious).

both genes located at a precise spot on a chromosome, one inherited from the father and the other from the mother they are located at exactly the same place.

a different origin from the original organism.

graft of cells, tissues or organs from a donor. Immunological compatibility between donor and recipient is not guaranteed. There are frequent risks of grafted organ rejection by the recipient organism.

muscular atrophy, reduction of muscle volume.

referring to analysis methods.

Animal model
animal with a spontaneous or experimentally induced disease, used to study the human disease or for pharmacolgical studies

substances that decrease or suppress pain.


substance that blocks the action of acetylcholinesterase, preventing the degradation of acetylcholine

protein produced by the immune system (especially B lymphocytes) in response to the penetration of a foreign molecule in the organism. It is tightly bound by the antibody to inactivate it or to label it for elimination by the organism.

Anti-acetylcholine receptor antibodies
antibodies targeted specifically to the muscle receptor to acetylcholine. These antibodies bind to the receptors preventing the attachment of acetylcholine and the propagation of nervous conduction.

molecule inducing production of antibodies specifically targeted against it.

Antisense RNA

RNA complementary to messenger RNA. When combined with messenger RNA, translation of the latter is blocked.

cells providing support functions to the central nervous system.

Adenosine triphosphate.

volume reduction of an organ or tissue due to varied pathological lesions.

Auto antibody
antibody produced against one’s self (and not against a foreign substance).

disease involving the production of antibodies against a part of one’s self (auto-antibodies).

Autograft or autologous graft
graft of cells, tissues or organs coming from one’s own body.

Autosomal dominant
mode of transmission of a hereditary disease in which the patient received a chromosome from a sick parent bearing the gene anomaly. The involvement of only one parent by the disease is sufficient to transmit the disease to the child with a risk of 1/2 (50%) at each pregnancy.

Autosomal recessive
mode of transmission of a hereditary disease in which the patient received two chromosomes bearing the gene anomaly, one from each parent. For these parents, the risk of transmitting an autosomal recessive disease is 1/4 (25%) at each pregnancy.

Auxiliary virus (helper virus)
AAV is incapable of carrying out a replication cycle in the course of cell infection. The presence of another virus, called a helper (auxiliary), provides additional functions needed for viral replication and leads to a productive infectious cycle. This dependency is the origin of the genus name of AAVs (dependovirus).




Bank of genes/cells/tissus
institution that collects and stores DNA/cells/tissues (frozen) of individuals or organisms for their study or preservation.

surgical sampling of a small sample of an organ (muscle, skin,…) most often under local anesthesia, for microscopic or pathologic examination.



heart muscle cells.

CD8 and CD4
molecules expressed by sub-populations of T lymphocytes involved in cellular interactions during the immune response. They interact with molecules of the MHC present on antigen presenting cells

cDNA (complementary DNA)
single strand sequence of DNA. Generated in vitro by copying a strand of RNA using a polymerase enzyme. A sequence of cDNA is also called a “transcript”.

Cell culture
all the techniques used to grow cells in an artificial medium under sterile conditions.

Cell therapy
process involving the transfer of cells (modified or not) into an organism for therapeutic purposes.

physical form of DNA associated with proteins during cell division (appearing as fine rods). It is composed of two arms, a long arm and a short arm. By convention, the long arm is called q and the short arm is called p. Human cells contain 23 pairs of chromosomes, i.e. 46 chromosomes. 22 pairs are composed of 2 identical chromosomes, called autosomes. The 23rd pair is composed of gender specific chromosomes, XX in women and XY in men.

Clinical trial
therapeutic assessment in patients of a new gene therapy strategy (in our context).

cells (or organisms) arising from the same cell and so genetically identical among them and with the mother cell.

see genetic code.

ability of a cell to contract in presence of a suitable stimulation.

Creatine phosphokinase (CPK)
muscular enzyme that is released in the bloodstream in case of muscular lesion.

CTL response
specific cellular immune response mediated by killer cells, mainly CD8 cytotoxic T Lymphocytes but also CD4.

cellular framework. In muscle cells, the cytoskeleton is partially composed of contractile elements, myofibrils, but also of dystrophin and proteins associated with it.



loss of a fragment of DNA (or of a gene).

Différential diagnosis
diagnose by comparison of the condition of the patient to patterns from diseases sharing similarities, based on the examination of the specific clinical condition and on results from additional assays (blood tests, muscle biopsy, EMG…).

DNA (deoxyribonucleic acid)
DNA is a complex macromolecule that is the support of heredity (genes). It is the matrix of chromosomes. DNA is organised in a double helix (two complementary strands) containing four nucleotides adenine, guanine, cytosine and thymidine.

in genetics, this is the characteristic of an allele who requires only one copy of a given gene to be expressed. This single copy may come from either parent.

analogue of tetracycline used, in conjunction which a regulatable expression cassette, to control the expression of genes.


large protein of sarcolemma. Duchenne muscular dystrophy (DMD) is a disease resulting from a deficiency in the dystrophin gene.



capacity of muscle fibers to stretch and resume their normal length.

Electromyogram (EMG)
plot of the electrical activity produced by muscular contraction, recorded by a fine needle inserted in the muscle. It is used to determine the origin of muscular problems muscles or nerves.

separation of molecules (proteins or nucleic acids) in an electric field as a function of their molecular weight and/or their electric charge.

method involving electric pulses to improve transduction in skeletal muscle after injection of naked DNA. This technique is based on two principles increasing cell membrane permeability and penetration of DNA by electrophoresis.

Encapsidation cell
modified cell containing elements expressing proteins to produce empty viral particles not expressing any transgene.

brain pathology of varied origins (metabolic, degenerative, genetic, …)

protein catalysing a specific biochemical reaction

Epithelial cells
cells lining the external part of internal cavities of the organism, e.g. the digestive tract.

small antigenic part of a molecule.

hormone that stimulates the production of red blood cells.

ES cells
totipotent Embryonic Stem cells

Ex vivo ou in vitro
experiments carried out outside a living being (ex vivo), in the laboratory (in vitro).

coding segment of DNA in a gene.

Expression vector
virus or plasmid that harbours a DNA sequence constructed in the aim of expressing a specific protein into a host cell.



Facteur IX
protein involved in the process of blood coagulation, lacking in certain forms of haemophilia.

Flexures or contractures
permanent stiffening of a joint in flexion (elbow, hip,…): it can no longer be extended and stiffening is often painful.



sequence of DNA composing a unit of genetic information. One gene codes for one protein, thereby ensuring a precise function. A gene can contain sequences that code (exons) and sequences that do not code (introns).

Gene therapy
set of therapeutic approaches involving the transfer of genetic information to cells, tissues or organs of a patient, in order to overcome a genetic default or to provide a protective or corrective function.

Gene therapy ex vivo
type of gene therapy in which cells are removed from a patient, genetically modified by a vector carrying the therapeutic gene outside the body and are then re-introduced in the same patient.

Genetic code
used to translate the message coded in the gene into a protein. One sequence of 3 nucleotides (codon) corresponds to one amino acid (of the protein).

Genetic counselling (consultation)
information given by a geneticist during a consultation, to every person with a genetic disease or related to the afflicted person, in order to determine the risk of being affected or of transmitting the disease.

Genetic engineering
methods of investigation and of experimentation on genes (cloning, synthesis of a therapeutic protein…)

Genetic linkage
probability with which two neighbouring genes (on the same chromosome) can be transmitted together in case of rearrangement of the genetic material.

Genetic map
Markers located along the length of each chromosome. These markers enable genes located on different chromosomes to be localised.

Genetic marker
sequence of DNA transmitted within a family in the same way and at the same time as the gene involved in the genetic disease, and that is used as a marker when searching for the gene.

Genetic recombination
exchange of fragments between two DNA molecules that can cause mutations.

the entire DNA of an organism.

GLP (“Good Laboratory Practices”)
Good Laboratory Practices

GMP (“Good Manufactory Procedures”)
procedures guaranteeing quality



Hematopoietic stem cells
cells which are at the origin of all types of blood cells (red cells, white cells, platelets).

transformation of venous blood rich in carbon dioxide in pulmonary alveoli, into arterial blood rich in oxygen.

transmission of genetic characters from one generation to another.

compatibility between two organs or tissues so that a graft (of an organ or of cells) is not rejected. This compatibility depends on the genetic similarities between donor and recipient.

microscopic examination of tissues

HLA (“Human Leucocyte Antigens”)
assay of certain molecules present on white blood cells histocompatibility antigens. Depending on their mutual combination, these antigens mark the particular character of an individual and play an essential role in its defence..

increase in the volume or size of an organ.

low levels of glucose in blood.

decreased muscle tone (“limpness”).



Immune barrier
faced to a foreign substance, the organism defends itself by mobilising a large number of cells and manufactures antibodies to neutralise it.

technique used to assess the presence of a specific protein in tissue sections (prepared from a biopsy) by use of a specific antibody, which binds to it, thereby allowing visualisation.

technique allowing the visualisation of a specific protein in cells or tissue sections (prepared from a biopsy) by binding a specific antibody conjugated to a fluorescent substrate.

that induces a strong immune reaction.

proteins with antibody activity that play an essential role in defending the organism against foreign proteins.

drug which limits the immune response used to treat some auto-immune diseases or after a graft.

In vitro (ex vivo)
“in glass”, laboratory experiments outside the organism.

In vivo
in the living, inside the organism.

non-specific reaction caused by an exogenous harmful stimulus.

Intercostal muscles
thorax muscles, located between the ribs. Together with the diaphragm, they allow inspiration. When they relax, the air leaves the lungs this is expiration.

Intra-arterial injection
technique of high-pressure intra-vascular administration that enables the therapeutic gene to reach groups of skeletal muscles that are irrigated by the artery.

non-coding part of a gene.

atom or group of atoms with a positive or negative electric charge.

Ion channel
cell membrane pore allowing for ion passage.



unit of length for nucleic acids, equivalent to 1000 base pairs.

organism in which a gene has been invalidated and replaced by another gene.

organism in which a gene has been invalidated.



family of slow retroviruses that can infect quiescent cells (not dividing cells).

artificial lipid constructs used for DNA transport. The composition of its outer envelope is similar to that of the cell membrane, enabling it to fuse with the membrane and release the DNA inside the cell.

Locus (plural: loci)
position of a gene in the genome. The locus of a gene is designated by the chromosome number, its arm, and its place. For example, the Duchenne muscular dystrophy gene is at locus Xp21, meaning it is at locus 21 of the short arm (p) of the X chromosome.

a subset of white blood cells. These small cells with a round and voluminous nucleus are involved in specific aspects of immune reactions. There are two categories of lymphocytes B lymphocytes (that secrete antibodies) and T lymphocytes.



large molecule resulting from the assembly of small molecules, for example proteins that are formed from amino acids, and nucleic acids (DNA and RNA) that are formed from nucleotides

Messenger RNA
strand of RNA that is translated from the genomic DNA, and leaves the cell nucleus to reach the cytoplasm where it is used as a matrix for the synthesis of a protein

enzymatic transformation of organic molecules. Synthesis corresponds to anabolism, and degradation to catabolism.

organic substance resulting from enzymatic reactions. .

Major Histocompatibility Complex set of genes coding for proteins involved in antigen presentation.

Molecular biology
branch of biology that deals with nucleic acids and proteins, at the molecular level.

Molecular cloning
in vitro insertion of a fragment of DNA, in a vector that replicates autonomously in the host cell (often bacteria). Growing this cell containing the recombined vector enables the inserted DNA to be isolated pure and in high quantity.

Molecular genetics
study of the biochemical constitution of the genetic material (replication, repair, expression and regulation of its functions).

category of white blood cells (the biggest in terms of size).

Motor neurone
nerve cell transmitting movement orders between the spinal chord and muscles. These cells are located in the front part (anterior horn) of the spinal chord. The motor neurone is composed of a cellular body containing the nucleus and a prolongation, the axon, that connects to the next motor neurone or to a muscle via the motor end-plate (synapse).

Muscle fasciculations
repetitive, spasmodic, spontaneous muscle contractions visible to the naked eye.

Muscular dystrophy
muscle involvement characterised by progressive volume loss and weakening of certain groups of muscles.

Muscular testing
method for manual determination of the force of the main muscle groups. Measurement is based on a scale from 0 (no force) to 5 (maximal muscular force).

abrupt and transmissible modification of the genetic material. It may be spontaneous or induced by agents called mutagens (UV, radiation, toxic products,…).

whitish substance surrounding nerve fibres, involved in the transmission of nerve influxes.

precursor (that will give) cell muscle cells (or fibres).

heart muscle.

of muscular origin.

abnormal slowness of muscle relaxation after a voluntary or provoked contraction (for example a handshake that the patient has trouble releasing).



mutation of a gene involving a sole individual for the first time.

Nerve conduction velocity
speed at which nerves transmit nervous influx. It is expressed as meter per second. The velocity of normal motor nerve conduction is about 40 to 45 m/s.

Neuro-muscular junction
see Synapse

of nervous origin.

Northern blot
technique for analyzing RNAs, in particular messenger RNA, by electrophoresis followed by transfer and hybridization with a labeled nucleotide marker on a filter.

Nucleic bases
substances that compose nucleic acids (adenine-A-, cytosine-C-, guanine-G-, thymine-T- for DNA or uracil-U- for RNA). These bases are complementary two-by-two A with T or U, C with G. This property explains the double helix structure of DNA.

molecules constituting the DNA chain. There are four nucleotides, composed of nucleic acid bases combining two-by-two (base pairs).



cells producing myelin in the central nervous system.

participating in the development of a cancer.


differential sub-cellular compartment whose activity contributes to cellular activity, e.g. mitochondria.
network of inert artificial fibres to which genetically modified cells are bound, for example to produce the missing protein.



any route of administration of a substance other than via the digestive tract (intravenous, subcutaneous, …).

causing disease.

polymerase chain reaction, a technique that uses an enzyme (DNA polymerase) to repeatedly amplify specific regions of a DNA molecule, as a result of cycles of denaturation, polymerisation and elongation.

Perfect tetany
force developed by the muscle fibre in response to a complete fusion of electric or nervous twitches

capacity of a given cell type to be infected by a virus (or a vector).

treatment with drugs (small molecules).

Physical map
it is used to localise genes (indicate position) by having direct access to the DNA fragment containing it.

Polymorphism (polymorphic sequences)
that which can assume several forms. In the case of DNA, these are sequences that are highly variable in different individuals.

Post-synaptic membrane
muscle membrane that receives nerve influx through the synapse

position in which a person is maintained for a given time (from several minutes to several hours) for therapeutic purposes, for example to prevent or correct a deformation of the skeleton or a retraction of muscles.

Pre-synaptic membrane
membrane that ends nerves. It releases nerve influx (in the form of acetylcholine molecules) into the synapse.

Preclinical studies
studies conducted in vivo, i.e. in non-human animal models, in order to assess the efficacy and safety of gene transfer. These studies are indispensable and precede clinical trials in humans.

Prenatal diagnosis
medical practices intended to detect a disorder of special importance in the embryo or foetus during pregnancy. It must be preceded by a genetic counselling consultation.

specific sequence of DNA or RNA, known and labelled with a radioactive substance, used to detect a complementary sequence of DNA or RNA.

Producing cells
transformed cells containing all the biological elements necessary for the production of a viral vector (genome, envelope).

macromolecule formed by the chaining of amino acids, encoded by a gene. Every protein has a precise role in the organism.


One or several techniques used to increase the purity of a molecule or a chemical compound.



see autosomal recessive

Regulation of expression
molecular mechanisms that control the level of expression of genes in the cell. The control points can be transcription and translation.

identical duplication, a characteristic property of the DNA molecule.

Respiratory muscles
muscles of the thorax that enable respiration. They are primarily the intercostal muscles and the diaphragm.

Restriction enzyme
enzyme capable of cutting DNA at a specific nucleotide sequence.

Retractions (muscular)
abnormal modifications of a muscle, that becomes less voluminous, shorter, and harder.

virus of which genetic material is RNA that is reverse-transcribed into DNA (in the host cell) by the enzyme reverse transcriptase.

Reverse transcriptase
viral enzyme that reverse-transcribes a molecule of RNA into a molecule of DNA. It is required for the multiplication of retroviruses.

RNA (ribonucleic acid)
macromolecule composed of a single chain of nucleotides (single strand) resulting from the transcription (copy) of DNA.



membrane glycoprotein complex associated with dystrophin. It is composed of four sub-units, ?, ?, ? and ?. Mutations of these proteins have been identified as being responsible for muscular dystrophies.

structural and functional unit of muscle between the two Z lines

Sarcoplasmic reticulum
network of intracellular cavities that plays an important role in protein synthesis.

Satellite cells
cells that are capable of multiplying and reforming muscle fibres under certain conditions. They are responsible for normal regeneration following destruction of muscle (trauma, infection, …).

Scale up
process used to go from a small-scale production (several culture dishes) to a larger scale (a reactor of several litres).

Schwann cells
cells producing myelin in the nervous system.

Sensory nerve
nerve which transmits perceptions and/or sensations perceived in/on the body to the brain.

see viral strain.

liquid obtained by separation of cells from the blood. It contains components that can be assayed.

Skeletal muscles
see striated muscles.

Smooth muscles
they are located inside the walls of blood vessels, of the digestive tract, and in certain organs such as the uterus. They are not voluntarily commanded. They do not have the same constitution as skeletal muscles (they are not striated).

Standard operating procedure.

Southern blot
transfer of DNA molecules separated by size, from a gel to a flexible membrane (nitrocellulose or nylon).

Sporadic (case)
isolated case.

Striated or skeletal muscles
attached to the skeleton, they are inserted into bones via tendons. They are called “striated” because the organisation of contractile myofibrils (actin and myosin) in the fibres gives them a striated, or banded, appearance under the microscope.

replacement of one base by another in DNA, leading to a mutation in the genome.

Synapse or neuro-muscular junction
junction between two nerve cells or between a nerve cell and a muscle cell, by which nervous influx is transmitted. The transmission of nervous influxes from one cell to the next is done via the release of a chemical mediator into the space between the two cells, called the synaptic cleft.



T Lymphocytes
type of white blood cell specialised in certain immune reactions. There are several types of T lymphocytes (T3, T4, T8 lymphocytes, suppressor lymphocytes…), each fulfilling specific needs. T lymphocytes do not secrete antibodies.

T cell receptor expressed on T lymphocytes, responsible for the recognition of epitopes.

Tomography (CT scan)
technique used to study the human body through the imaging of radiological slides of the organs.

non-differentiated embryonic stem cells capable of developing into an entire organism..

Transcriptase inverse
Enzyme permettant la transcription d’une molécule d’ARN en une molécule d’ADN. Elle est indispensable à la multiplication des rétrovirus.

transfer of genetic information of a gene from a molecule of DNA to a molecule of messenger RNA (transcript).

messenger RNA synthesised from a segment of DNA.

deliver a heterologous gene to a cell and have it expressed

gene transferred to a new organism for expression

mother transmitting a disease to her child, whether or not she may be afflicted with the disease.

force developed by muscle fibre in response to a unique electrical or nervous stimulation.



technique for the sedimentation of particles subjected to extremely rapid rotation.

protein analogue to dystrophin, but located at the neuromuscular junction.



genetic element that can bring the “gene-drug” inside the target cell. The main vectors currently used in gene therapy are derived from modified non-infectious viruses.

study and improvement of vectors.

they are the smallest living micro-organisms. In order to multiply and survive they have to behave as parasites of cells of which enzymatic machinery is “hijacked” for their own benefit..

Viral strain
sub-groups of a given virus species that differ slightly in only some of their features. One can also speak of serotypes which differ in their antigenic reactivity in their host.



Western blot
transfer of proteins from a gel to a flexible membrane (nitrocellulose or nylon) after separation by electrophoresis and identification by a specific antibody.

X-linked recessive
mode of transmission of a genetic character that is expressed only if the genes coding for it are on the two X chromosomes in women or the unique X chromosome in men.

YAC (Yeast artificial chromosome)
artificial chromosome of yeast used to clone large fragments of DNA.