Genetic testing and counselling in carrier screening for serious hereditary diseases

Our genetic blueprint consists of 23 pairs of chromosomes, giving 46 chromosomes. Every child inherits genetic information from both parents, with one chromosome of each pair coming from the mother and one from the father. Certain illnesses, such as cystic fibrosis, for example, can be inherited, but are only manifested if (1) both parents have a mutation in the same gene and (2) pass on this gene. This is known as recessive inheritance. The carrier of a recessive hereditary disease has a 50% risk of passing on the mutated gene to their offspring. If both parents are carriers of the same hereditary disease, there is a 25% likelihood that their children will inherit both parental mutations and thus develop the disease.  

Today, more than 1,300 recessive hereditary diseases have been identified. The exact genes to be tested are discussed in a genetic counselling consultation. Family history and genetic background are two of the factors governing the selection.

The 10 most frequent recessive hereditary diseases are:

• Cystic fibrosis (CF)      
• Alpha thalassaemia     
• Beta thalassaemia/sickle cell anaemia 
• Fragile X syndrome (FraX)                                           
• Duchenne/Becker muscular dystrophy (DMD/BMD)
• Spinal muscular atrophy (SMA)                                    
• Phenylketonuria (PKU)                        
• Congenital disorder of glycosylation type 1a (CDG1A)
• Smith-Lemli-Opitz syndrome    
• Medium chain acyl-CoA dehydrogenase deficiency

Together with the attending physician, the experts assess the added value of genetic analysis for the person concerned during the first counselling session. A consultation can be particularly helpful for the following people:

• Couples who are thinking about family planning.
• Persons who, before they start a relationship, want to know whether they are carriers of a hereditary disease and therefore may be at a higher risk of passing on this disease to their children.
• Relatives of persons who already know that they are carriers of a hereditary disease.
• Couples who are related. 

1. Initial consultation between the attending physician or Precise expert and the patient to discuss the genes to be tested and to explain the patient's rights. At the end of the consultation, written consent is given and a blood sample is taken. 
2. Genetic analysis including evaluation in the Precise laboratory and writing up of a clinical report of the findings.
3. Second consultation between the attending physician or Precise expert and the patient to discuss and classify the findings and possibly discuss how to proceed further. 

Genetic counselling is covered by the basic insurance as a normal medical consultation and is billed via Tarmed. The costs of carrier testing are not reimbursed by compulsory health insurance

and must be borne by the person seeking the genetic test. In the context of prevention, certain supplementary insurances cover the cost of genetic analysis as an innovation factor. Contact your health insurance for more detailed information on your cost coverage.