Introduction
Genetic screening is a type of genetic testing that is designed to identify a specified population at a higher risk of having or developing a disease with the aim of prevention or early treatment (Andermann & Blancquaert, 2010). Generally, genetic screening is performed as targeted testing for known hotspot variations. The development of next-generation sequencing (NGS) techniques has introduced a new genomic era by producing massive genomic data and reducing costs. Recently, the Genome Aggregation Database (gnomAD, https://gnomad.broadinstitute.org/) has been constructed as a very large database that contains genomic information of the general population worldwide (Karczewski et al., 2020; Lek et al., 2016). Several companies have launched proactive genetic testing for generally healthy individuals without a personal or family history using NGS techniques for identifying particular genes or performing whole exome/genome sequencing that is not confined to hotspot variations.
At present, major questions are how genomic information of a generally healthy population reflects probabilities of developing diseases and the differences in those probabilities among ethnic groups. Additional questions are the use of genetic testing to provide useful and crucial information and eventually prevent diseases in healthy individuals. To answer these questions, genomic data associated with congenital hypothyroidism, which is one of the major achievements of preventive medicine (Buyukgebiz, 2013), were analyzed based on the general population database and their carrier frequency and genetic prevalence were estimated by ethnicity.