Autosomal Dominant Polycystic Kidney Disease (ADPKD)
Clinical features: Approximately one-half of individuals with ADPKD have end-stage renal disease by 60 years of age. Extra-renal manifestations of ADPKD include polycystic liver disease (75% by 50 years) and intracranial aneurysms (10%). Considerable variability of both the severity of the renal disease and the extra-renal manifestations occurs even within the same family. This is known as variable expression. The current management for individuals with ADPKD is aimed at reducing both the morbidity and mortality from the renal and extrarenal complications of the disease.
Incidence: ADPKD is common. Its prevalence is between 1 in 400 and 1 in 1,000.
Inheritance: Autosomal dominant. Approximately 90% of affected individuals have an affected parent, in the remaining 10% the condition occurs as the result of a new mutation.
Gene: Nearly always caused by mutations in the polycystin 1 gene, PKD1 on chromosome 16 (85%) or mutations in the polycystin 2 gene, PKD2 on chromosome 4 (15%). There is evidence to suggest at least one further locus in a few families. About 200 different PKD1 mutations and more than 50 different PKD2 mutations have been described. DNA testing by linkage analysis or direct mutation detection is available but very complicated due to genetic heterogeneity and to the large size of both PKD1 and PKD2. Advice from the local clinical genetics service should be sought before investigations are undertaken.
Prenatal diagnosis: Rarely requested. Possible if a mutation is identified in the affected individual or appropriate DNA linkage studies have been undertaken in the family. A family considering prenatal diagnosis should be referred to the local clinical genetics service prior to a pregnancy. This ensures family members are offered appropriate advice and investigations, to confirm whether or not prenatal diagnosis is possible.
Presymtomatic testing : It is recommended that first degree relatives of an individual with ADPKD are assessed by renal ultrasound scans. DNA methods of evaluation may be possible in some families.
The Polycystic Kidney Disease Charity PO Box 141 Bishop Auckland County Durham DL14 6ZD Tel: 01388 665 004 Web: www.pkdcharity.co.uk
If you would like to access specialist information on Adult Polycystic Kidney Disease or Autosomal Dominant Polycystic Kidney Disease please go to:- Genetests - Adult polycystic kidney disease
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