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Familial phenotype differences in PKD11
N Hateboer1, L P Lazarou, A J Williams
1Institute of Medical Genetics, University Hospital of Wales, Heath Park, Cardiff, United Kingdom. Hateboer@Cardiff.AC.UK
Insights
Differences in clinical severity exist between families with autosomal dominant polycystic kidney disease (ADPKD) caused by PKD1 gene mutations. These familial phenotype variations suggest diverse underlying genetic causes for ADPKD.
Area of Science:
- Genetics and Molecular Biology
- Nephrology
- Clinical Genetics
Background:
- Mutations in the PKD1 gene are the primary cause of autosomal dominant polycystic kidney disease (ADPKD), the most common and severe form.
- While intrafamilial variability in ADPKD severity is recognized, inter-familial differences in clinical presentation remain uncertain.
Purpose of the Study:
- To investigate whether distinct clinical severity differences exist among different families affected by PKD1-linked ADPKD.
- To explore the association between unique disease-associated haplotypes and observed phenotype variations across families.
Main Methods:
- Study included ten large South Wales ADPKD families with at least 12 affected members each.
- Clinical data, including survival and ADPKD-associated complications, were collected from affected individuals.
- Linkage and haplotype analysis using microsatellite markers near the PKD1 gene were performed; survival data analyzed using Kaplan-Meier and log-rank tests.
Main Results:
- Haplotype analysis confirmed PKD1 linkage in all families, with each family exhibiting a unique disease-associated haplotype.
- Significant inter-familial differences were observed in overall survival (P=0.0004), renal survival (P=0.0001), hypertension prevalence (P=0.013), and hernia occurrence (P=0.048).
- Hypertension was associated with significantly worse overall and renal survival.
Conclusions:
- Phenotype differences are confirmed to exist between different PKD1-linked ADPKD families.
- These variations are likely attributed to a heterogeneous spectrum of underlying PKD1 mutations, indicated by unique disease-associated haplotypes.
Unlabelled:
Familial phenotype differences in PKD1.
Background:
Mutations within the PKD1 gene are responsible for the most common and most severe form of autosomal dominant polycystic kidney disease (ADPKD). Although it is known that there is a wide range of disease severity within PKD1 families, it is uncertain whether differences in clinical severity also occur among PKD1 families.
Methods:
Ten large South Wales ADPKD families with at least 12 affected members were included in the study. From affected members, clinical information was obtained, including survival data and the presence of ADPKD-associated complications. Family members who were at risk of having inherited ADPKD but were proven to be non-affected were included as controls. Linkage and haplotype analysis were performed with highly polymorphic microsatellite markers closely linked to the PKD1 gene. Survival data were analyzed by the Kaplan-Meier method and the log rank test. Logistic regression analysis was used to test for differences in complication rates between families.
Results:
Haplotype analysis revealed that each family had PKD1-linked disease with a unique disease-associated haplotype. Interfamily differences were observed in overall survival (P = 0.0004), renal survival (P = 0.0001), hypertension prevalence (P = 0.013), and hernia (P = 0.048). Individuals with hypertension had significantly worse overall (P = 0.0085) and renal (P = 0.03) survival compared with those without hypertension. No statistically significant differences in the prevalence of hypertension and hernia were observed among controls.
Conclusion:
We conclude that phenotype differences exist between PKD1 families, which, on the basis of having unique disease-associated haplotypes, are likely to be associated with a heterogeneous range of underlying PKD1 mutations.