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Review
. 2025 May-Jun;25(3):177-184.
doi: 10.1016/j.ipej.2025.05.002. Epub 2025 May 27.

Basic principles of genetics and genetic counselling

Nina J Beelen  1 , Jitendra Vohra  2 , Job A J Verdonschot  3
Affiliations
Review

Basic principles of genetics and genetic counselling

Nina J Beelen et al. Indian Pacing Electrophysiol J. 2025 May-Jun.

Abstract

Genetic counselling and testing is a fast growing field in modern medicine. Genetic analysis can aid in the diagnosis, treatment, management and prevention of (genetic) diseases in patients. This review provides an overview of the fundamental principles of genetics from a clinical perspective, focusing on the practical application and interpretation of genetic testing. Key concepts, including genetic expression and inheritance patterns, are discussed to give a better understanding of the subject. There is a large variety of genetic testing methodologies, from single gene testing to whole genome sequencing (WGS) that have their respective advantages, disadvantages and clinical implications. Interpretation of genetic results is performed on different levels: from the molecular level (variant interpretation and classification) to the clinical level (association of genetic variants with disease and phenotype). The correct interpretation of the results is essential to use genetics for clinical decision making. Challenges in the field include, but are not limited to, variants of unknown significance, incidental findings, and the familial forms of disease that remain gene-elusive with the current technologies. Pre- and post-test genetic counselling is essential to ensure that patients and their family members are aware of the options and implications of genetic testing, which will significantly benefit patients with coping. This review is based on the latest European and American guidelines, to give an up-to-date overview of rapid advancements of genetic testing and counselling. A dedicated follow-up article in this series will explore the Indian perspective in greater depth.

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Conflict of interest statement

Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Fig. 1
Fig. 1
Autosomal dominant and autosomal recessive inheritance patterns. Abbreviations as in text.
Fig. 2
Fig. 2
X-linked dominant and X-linked recessive inheritance patterns. Abbreviations as in text.
Fig. 3
Fig. 3
Mitochondrial inheritance pattern.
Fig. 4
Fig. 4
Incomplete penetrance and variable expression.
Fig. 5
Fig. 5
Overview of variant types and their implications.
See this image and copyright information in PMC

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