Predictive genetic testing GEN-TEST 1

Genetic testing is a fundamental starting point for understanding the nature of hereditary conditions. It involves identifying disease-causing genes and detecting genetic variants (mutations) in those genes. Even if both partners planning to start a family are healthy, they may be carriers of the same recessive (hidden) mutation. In such cases, there is a 25% risk that their child will be born with a serious lifelong genetic condition. It is estimated that more than 1,300 hereditary diseases are inherited in this way, and the risk of having an affected child is 25% when both partners are carriers of the same recessive mutation.

If predictive genetic screening (performed prior to conception) reveals that both partners are carriers of a serious genetic condition, appropriate assisted reproduction methods can be recommended to prevent transmission of the disease to the embryo.

One such method is GEN-TEST 1, which analyzes 13 genes associated with the most common severe recessive disorders in the Central European population. These include, for example, cystic fibrosis, spinal muscular atrophy, and selected metabolic and hematological disorders. This test detects the most common pathogenic variants (mutations) in healthy prospective parents that may affect the health of their offspring. If no mutations are identified in either partner, the risk of having an affected child is significantly reduced.

In specific cases, the basic screening panel can be expanded. For example, if the tested individual has non-Central European ancestry, genes relevant to the specific ethnic background may be included in the analysis.

In the Czech Republic, approximately 1 in 40 individuals is a carrier of SMA. It is a neuromuscular disorder characterized by progressive weakness of voluntary muscles and later also the respiratory muscles. Affected individuals gradually lose mobility and develop severe breathing difficulties, and are almost always wheelchair-dependent. Due to the variability of clinical presentation, life expectancy ranges from 1 to 50 years.

If both partners are carriers of mutations in the Connexin 26 gene, 25% of their children will be affected by congenital deafness. Mutations in the Connexin 26 gene account for the majority of genetically determined hearing loss. The frequency of healthy heterozygous carriers in the general European population is high, reaching nearly 3% (1 in 31).

Cystic fibrosis (also known as “salt-loss syndrome”) is the most common autosomal recessive disorder in the Czech Republic. It is estimated that up to 1 in 30 individuals is a carrier of CF. More than 600 different mutations in the CFTR gene contribute to the development of the disease. These mutations can occur in various combinations, resulting in considerable clinical variability. If both partners carry the same CFTR mutation, there is a high probability that their child will be affected by this serious condition.

Affected individuals typically suffer from chronic respiratory disease. Common complications include malabsorption due to pancreatic insufficiency, diabetes mellitus, liver cirrhosis, osteoporosis, and other associated conditions. CF, or even CF carrier status, may be a cause of male infertility. In women with CF, fertility depends largely on their overall health status.

Lactose intolerance is a partial or complete inability to digest lactose (milk sugar). Symptoms include bloating, diarrhea, nausea, and abdominal pain. It is estimated to affect 7–20% of the population.

DMD is an X-linked genetic disorder caused by the absence of dystrophin, a protein essential for normal muscle cell function. The disease affects males exclusively. Females are typically carriers, although mild symptoms may occasionally occur. By approximately 13 years of age, affected boys become wheelchair-dependent due to progressive muscle weakness. Premature death usually occurs between 20 and 30 years of age, most commonly as a result of cardiac or respiratory failure.