Figure 1

Clinical and genetic characterization of the T309I variant. (A) QTc interval length in the heterozygous T309I carriers (T309I +) and their unaffected relatives (T309I-), both at rest and in the 4th minute of exercise test recovery; ***statistical significance at P < 0.001; the graph was prepared using the software GraphPad Prism, version 6.05. (B) Scheme of T309I-Kv7.1 subunit (upper panel) and birthplaces of the oldest T309I carriers in every family (lower panel; the map was generated using the software QGIS, version 3.10, with data downloaded from https://www.arcdata.cz/produkty/geograficka-data/arccr-500). In the 2 families located in the central part of the country, some earlier ancestors from the eastern part could be identified. Nevertheless, none of them has been living at the time of the study and biological material was not available for molecular analysis. Thus, we can only speculate, whether these ancestors coming from the east really carried the variant, even if it is truly anticipated. (C) Family pedigrees; affected individuals in red, probands indicated with arrows. (D) Haplotype analysis of the KCNQ1 gene and surrounding regions (analysed STR markers shown in relative distances). The region shared by all affected individuals is framed by bold lines. Families with the same detected haplotype are divided into 3 subgroups (differentiated by colours); presumable ancestral haplotype is shown in blue. The uncoloured parts are unique in every single family; small crosses mark where crossing-overs occurred. Parts B, C, and D were prepared using the software Inkscape, version 0.92.2.