CRITICAL ELEMENTS OF GENETIC EVALUATION AND GENETIC COUNSELING
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Individual (affected or at risk) with Autosomal Dominant Polycystic Kidney Disease (ADPKD) |
Date: 6/19/98* |
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Disclaimer The "Critical Element of Genetic Evaluation and Genetic Counseling" was written and approved by genetic professionals and perinatologists within the state of Washington. The document is to act as an aid to medical geneticists, genetic counselors, and perinatologists who practice within our state. This Critical Element of Genetic Evaluation and Genetic Counseling does not define the applicable standard of care, nor is it intended to dictate an exclusive course for the diagnosis, counseling, treatment or management of genetic conditions or birth defects. The authors acknowledge that appropriate clinical practices may vary depending upon a number of factors including, among others, the needs and choices of the individual patient, the resources available, and limitations unique to the particular institution or type of practice.
Information obtained from patient/family 1. Review patient/family questions; reason for referral; knowledge base; perception of disease status and/or risk; what diagnoses have been considered; perceived notion about causation; assess need for professional interpreter: 2a. Using standard symbols, obtain family history (1st and 2nd degree relatives to consultand, and further removed as appropriate). Note ethnic background, consanguinity, ongoing pregnancies, and other significant family history. b. Additional directed family history: renal and hepatic disease, kidney dialysis and/or transplant, intracranial aneurysm, hypertension, valvular heart disease, age of onset of symptoms, ages and causes of death. c. Obtain relevant medical records on patient, including records of 1).appropriate tests/evaluations: ultrasound examination and age at examination; renal function studies; evaluation for hepatic cysts, intracranial aneurysms, and cardiovascular abnormalities; DNA studies, 2). records bearing on management, and 3). on other family members as needed: ultrasound examination and age at examination. 3. Obtain prenatal and perinatal history of patient, including prenatal exposures, pregnancy complications and prenatal testing, when appropriate. 4. Obtain past medical history (including environmental/occupational exposures) focusing on: renal and hepatic disease, kidney dialysis and/or transplant, intracranial aneurysm, hypertension, valvular heart disease, age of onset of symptoms, ages and causes of death. 5. Obtain information on growth and development, including school placement. For adult, also obtain information on education, employment and social functioning. 6. Assess family functioning and use of community resources. Assess personal, social, religious, ethnocultural issues. 7. Assess possible ethical concerns, such as confidentiality, non-paternity, insurability, discrimination, prenatal diagnosis: evaluation of an asymptomatic at-risk minor; testing of an asymptomatic individual before testing his or her asymptomatic at-risk parent. 8 Perform general physical examination of patient and/or other family members present if indicated, with attention to: 9. Other issues to consider: genetic counseling and testing to rule out ADPKD before using a relative as kidney donor
Information to be provided or discussed with the patient/family (this may occur in a series of multiple patient visits) 1. Summarize information obtained and discuss with patient/family the (possible) diagnosis and the degree of certainty of the diagnosis based on available information. 2. a). Recommend relevant tests/evaluations on patient and/or on other relatives which may include: Individuals considering presymptomatic DNA testing should explore the impact of positive, negative , and uncertain results in the area of insurability, employment, financial planning, family planning, relationships. DNA testing of asymptomatic children is not considered beneficial. Guidelines concerning presymptomatic and prenatal diagnosis are available from the National Kidney Foundation (see references).
b). Discuss sensitivity/specificity of test(s)/evaluation(s): Screening is available by ultrasound examination. Sensitivity increases with age. There is a risk of false negative results. DNA linkage is available, but requires a positive family history and sufficient living relatives whose ADPKD status is known to establish linkage phase. There is genetic heterogeneity. ADPKD1 gene is on chromosome 16 and is responsible for most (90%) of cases of the disease. ADPKD2 is on chromosome 4. 3. Discuss the following issues related to natural history: prognosis, developmental outcome/intellectual functioning, anticipated possible medical complications, including pregnancy related risks for affected women if indicated, and preventive measures: Early diagnosis may enhance control of blood pressure and early screening for other complications. End stage renal disease occurs by age 60 in about half of individuals with ADPKD. Persons with ADPKD1 develop renal failure at an earlier age than ADPKD2. Renal transplantation is often successful. Linkage testing in a family with ADPKD can be used to identify potential living related kidney donors. A pregnant woman with ADPKD may have complications especially if the woman has hypertension, proteinuria or renal insufficiency. 4. Review inheritance pattern (including penetrance and expressivity): autosomal dominant with age dependent penetrance. Symptoms variable and about 40% of affected individuals initially deny family history. After careful screening, only about 10% lack an affected relative. 5. Assess and discuss recurrence risk for future pregnancies, for affected and at risk individuals. Discuss general background risk for birth defects and recommendations for preconceptional and prenatal use of 0.4 mg folate per day. Include any additional risk based on family history/ethnicity/maternal age/maternal disease/maternal exposure/others. 6a. Discuss reproductive options (e.g. assisted reproductive technologies, adoption, taking risk and no additional pregnancies) when appropriate: Male affected: artificial insemination by donor; female affected: surrogacy (not using affected female relative). b. Discuss prenatal diagnostic options/issues: Prenatal diagnosis is available through genetic linkage testing. If possible, this should be considered and initiated prior to pregnancy because of time considerations. Couples who would not consider termination of a fetus determined to be at risk by linkage should be cautioned about pursuing prenatal diagnosis because this is analogous to testing an asymptomatic minor (or referral for discussion of) 7. Review management recommendations/options including screening protocols: management through renal clinics 8. Consider referral to: Nephrology 9. Address psychosocial issues including anticipatory guidance, patient and family reaction to diagnosis, need for community support services.
10. Address follow-up issues, such as genetic counseling for extended family members, including a plan for relaying test results: 11. Document clinic visit, including persons present, and subsequent substantive contacts (e.g. clinic note, +/- letter to referral source, +/- letter to family; other). Contact referring health care provider as appropriate. 12. Other issues to consider: 13. References and/or other protocols: Bear, JC et al. (1992) Autosomal dominant polycystic kidney disease: new information for genetic counseling. Am J Med Gen 43(3) 548-53. Beebe, DK (1996). Autosomal Dominant polycystic kidney disease. Am Fam Physician 53(3) 847-50 and 925-31. Hanning, VL et al (1991) Presymptomatic testing for adult onset polycystic kidney disease in at-risk kidney transplant donors. Am J Med Gen 40:425-28. Lieske JC and Tback FG (1993). Autosomal dominant polycystic kidney disease J of Am Soc Nephrology 3(8) 1442-1450. Michaud, J et al (1994). Autosomal dominant polycystic kidney disease in the fetus. Am J Med Gen 51(3) 240-6. National Kidney Foundation Workshop (1989). Gene Testing in Autosomal Dominant Polycystic Kidney Disease: Results of National Kidney Foundation Workshop. Am J Kidney Dis Vol XIII(2) 85-87. Reuss A, Wladimiroff, JW, and Niermeyer, MF (1991). Sonographic, clinical and genetic aspects of prenatal diagnosis of cystic kidney disease. Ultrasound in Med and Biol 17(7) 687-94.
* This Critical Element of Genetic Evaluation & Genetic Counseling was unanimously approved at a state genetics practitioners meeting on 6/19/98.
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