Genetic Screening of Atypical PKD Families
The Molecular Genetics and Biomarker Core offers sample collection, mutation screening and gene discovery services to facilitate the study of atypical autosomal dominant polycystic kidney disease (ADPKD) patients.
Atypical ADPKD presentations include extreme disease asymmetry (unilateral PKD), very early disease onset in childhood, atypical radiological patterns, unusual extrarenal disease manifestations and mild renal disease.
In addition, the core analyzes families in which no PKD1 or PKD2 mutation has been detected after research testing or clinical testing of both genes, as well as families with autosomal recessive polycystic kidney disease (ARPKD)-like disease or other ciliopathy-like phenotypes with PKD in which no mutation has been detected. Analysis varies depending on the features of the family.
The screening is research testing, but quality control and assurance principles similar to those in a clinical testing laboratory are used. There is typically no fee for this service.
- The referring clinician or geneticist contacts the core to determine the suitability of the family for analysis.
- For approved families, consent forms and blood draw kits (for DNA isolation) are sent to the referrer or family, and clinical information is collected.
- DNA is isolated from consenting family members' blood samples, or DNA from the consented patient is submitted. See DNA submission criteria.
- Samples are screened for mutations, with each deviation from the reference sequence evaluated to determine pathogenicity, as described in the ADPKD Mutation Database for the ADPKD genes.
- In cases where a clear mutation is not detected, screening for larger deletions by MLPA is employed.
- In mutation-negative cases, other follow-up studies include mutation screening of PKHD1 and HNF1B, and of the polycystic liver disease (PLCD) genes, when appropriate.
- In persistently negative families, targeted next-generation sequencing or whole-exome analysis or both are employed to identify a possible novel PKD gene.
- Because this is research testing, a detailed report of the findings is not provided to the referring clinician or geneticist, though the core works with clinically approved laboratories to confirm the data so that it can be used diagnostically.
For more information about these services, contact the core.