DNA diagnosis of mitochondrial diseases

Mitochondrial DNA (mtDNA) ANALYSIS: What valuable information does mtDNA analysis provide?

Mitochondria (from the Greek. Mitos - thread and khondrion - grain, grains) is a two-membered spherical or ellipsoid organoid with a diameter of about 1 μm. This is the only source of cell energy. Located in the cytoplasm of each cell, mitochondria are comparable to “batteries” that produce, store and distribute the energy necessary for the cell.

Human cells contain about 1,500 mitochondria. They are especially numerous in cells with an intensive metabolism (for example, in the heart, muscles and brain). Cells cannot function without mitochondria; life is impossible without them.

Mitochondrial DNA (mtDNA) - DNA located (as opposed to nuclear DNA) in mitochondria. In humans, mtDNA is a short double-stranded ring molecule that contains 37 genes and represents about 5% of the total DNA of the human genome.

Human mitochondria usually contain from two to ten identical copies of ring DNA molecules. The genetic code of mtDNA is slightly different from the genetic code of nuclear DNA. MtDNA contains structural genes encoding polypeptides, genes of ribosomal and transport RNAs. Many of the structural genes encode proteins responsible for the functioning of the respiratory systems and antibiotic resistance. MtDNA is inherited only through the maternal line and is transmitted from generation to generation exclusively by women.

What are the mtDNA mutations and why is their analysis very important?

Mutations in mtDNA occur, for various reasons, much more often than in nuclear DNA. Cells and tissues can contain both mtDNA of the same species (homoplasmy), and a combination of normal and mutant mtDNA in various ratios (heteroplasmy).

Point mutations, deletions or duplications of the mtDNA molecule are detected in mtDNA.

MtDNA mutations can cause maternally transmitted inherited diseases. Studies have shown that mtDNA mutations also accelerate the aging process and the development of age-related pathologies, for example, neurodegenerative diseases. In addition, they can cause a decrease in male fertility, increase the risk of miscarriage and fetal disorders. A decrease in the number of copies of mtDNA molecules also leads to the development of diseases such as myopathy, nephropathy, liver failure, etc.

MtDNA deletions and pathology

One of the important mutational events that occur in the mitochondrial genome is the formation of large deletions, leading to the loss of several genes and, as a result, to a certain deficiency of electron transfer chain proteins. The increased content of mtDNA molecules with deletion can lead to disruption of the oxidative phosphorylation process and a number of diseases. Studies have shown that large deletions of mtDNA can cause a decrease in male fertility, miscarriage and embryonic disorders, accelerated aging, can also contribute to the development of neurodegenerative diseases and a number of other diseases, such as mitochondrial myopathies (myositis with inclusion bodies, Kearns-Sayre syndrome, ophthalmoplegic myopathy, Pearson's syndrome, mitochondrial neurogastrointestinal encephalomyopathy, Leah's syndrome), cardiomyopathy, pancytopenia, sensorineural hearing loss. In addition, mtDNA deletions can reduce the survival rate of patients with renal failure and be a marker of success / failure of ECO.

How is mtDNA mutation analyzed?

Four deletions, which are studied in our clinic, lead to a complete or partial loss of 7-9 of 13 genes that encode polypeptides that affect the energy potential of the cell. The analysis includes a qualitative and quantitative study of mtDNA deletions, which is carried out by real-time PCR analysis and PCR analysis, which allows you to determine the presence of a specific deletion, as well as its percentage relative to the total number of mtDNA.

What is the peculiarity of the analysis of mtDNA mutations at the IGR Medical Center?

The diagnostic laboratory for its work uses only high-quality reagents of European and American production, as well as the latest equipment for molecular genetic research.

The study of mtDNA deletions includes not only analysis for the presence of deletions, but also an analysis of their quantitative composition. Such an integrated approach makes it possible to more accurately establish the composition of mtDNA deletions.

What biomaterial is taken for analysis?

The biomaterial is venous blood, sperm, embryo cells (depending on the type of analysis).

Studies are performed over 4 weeks.

You can get the results at the reception of the medical center.

Whatever the result of the karyotype, the doctors of our center will hold a qualified consultation and offer all possible options so that happiness comes to your family.

IGR Medical Center specializes in the diagnosis and treatment of all types of infertility:

• Comprehensive diagnosis of male and female infertility
• Laboratory diagnostics
• Intrauterine Insemination
• ECO
• ICSI
• Preimplantation genetic diagnosis
• Oocyte donation
• Surgical methods for obtaining sperm in severe forms of male infertility
• Cryopreservation of embryos, oocytes, sperm (vitrification)
• Pregnancy management
• Prenatal diagnosis

We are located  at the address Kiev, Victory Ave., 121-B.