Heterozygosity for human polycystic kidney and hepatic disease 1 ( PKHD1) mutations was recently associated with cystic liver disease and radiographic findings resembling medullary sponge kidney (MSK).
Given the limitations of antenatal ultrasound, this is only feasible by molecular genetics that became possible in 1994 when PKHD1, the locus for ARPKD, was mapped to chromosome 6p.
We also found enrichment on a genome-wide basis of heterozygous mutations in the autosomal recessive polycystic kidney disease gene PKHD1, indicating that adult PKHD1 carriers can present with clinical PCLD.
Given the limitations of antenatal ultrasound, this is only feasible by molecular genetics that became possible in 1994 when PKHD1, the locus for ARPKD, was mapped to chromosome 6p.
Molecular genetic investigations using whole-exome sequencing and confirmation using Sanger sequencing revealed a homozygous pathogenic mutation in PKHD1 underlying the clinical phenotype of ARPKD.
ARPKD is caused by mutations in the polycystic kidney and hepatic disease 1 (PKHD1) gene, which consists of 86 exons that are variably assembled into a number of alternatively spliced transcripts.
A mutation was characterized in the rat and screening the 66 coding exons of the human ortholog (PKHD1) in 14 probands with ARPKD revealed 6 truncating and 12 missense mutations; 8 of the affected individuals were compound heterozygotes.
A mutation was characterized in the rat and screening the 66 coding exons of the human ortholog (PKHD1) in 14 probands with ARPKD revealed 6 truncating and 12 missense mutations; 8 of the affected individuals were compound heterozygotes.
Despite the wide clinical spectrum of ARPKD (MIM 263200), genetic linkage studies indicate that mutations at a single locus, PKHD1 (polycystic kidney and hepatic disease 1), located on human chromosome region 6p21.1-p12, are responsible for all phenotypes of ARPKD.
To determine the molecular mechanism of the cystogenesis in ARPKD, we recently generated a mouse model for ARPKD that carries a targeted mutation in the mouse orthologue of human PKHD1.
Autosomal recessive polycystic kidney disease (ARPKD) and autosomal dominant polycystic kidney disease (ADPKD) are genetically distinct, with ADPKD usually caused by the genes <i>PKD1</i> or <i>PKD2</i> (encoding polycystin-1 and polycystin-2, respectively) and ARPKD caused by <i>PKHD1</i> (encoding fibrocystin/polyductin [FPC]).
Based on these observations, the next challenges will be to determine how various factors, such as specific mutations in the ARPKD gene, PKHD1(polycystic kidney and hepatic disease 1), variations in modifying gene loci, modulation by as yet unspecified environmental factors, and/or gene-environment interactions contribute to the marked variability in survival and disease expression observed among ARPKD patients.