PKHD1 and autosomal recessive polycystic kidney disease: Our study was performed within the research project in order to provide a first glimpse of the composition of mutations in Czech ARPKD patients (no study on this topic had previously been done in the Czech Republic), to determine the phenotype-genotype correlations in patients together with gradually setting up molecular analysis of the PKHD1 gene by amplicon-based next-generation sequencing.