Genetics
The disease is transmitted by autosomal dominant inheritance. So,
50% of offsprings inherit the abnormal gene.
Clinical Features
A. Renal Manifestations
- Less than 5% of nephrons are involved in cyst formation. Clinically,
most patients will have no detectable cyst at birth. Several small cysts
will appear in childhood, and during adulthood, the cysts grow and
kidney may be as large as 40 cm in length and over 8 kg in weight. - By the age of 50, nearly 30% of patients, will develop end stage renal
failure and by the age of 73 the figure becomes nearly 50%.
Hypertension will manifest before the development of renal failure in
60% of cases. Also, the inability to concentrate urine (polyuria and
nocturia) and metabolic acidosis will appear earlier. Episodic dull
aching abdominal pain which is due to cyst enlargement and persistent
abdominal fullness by large kidneys are other common complaints. - Renal complications include:
(a) Increased incidence of renal adenoma, and renal cell carcinoma.
(b) Haematuria which may be gross or microscopic in 50% of cases
secondary to cyst rupture into the pelvis, infection,
nephrolithiasis or owing to malignancy.
(c) Infection which may be difficult to treat if involving the cysts.
(d) Nephrolithiasis.
(f) Non-nephrotic range proteinuria in 30% of cases.
B. Extra-Renal Manifestations
- Cardiovascular involvement.
With ADPKD, there is a higher incidence of mitral valve prolapse
(30% while it is only 6% among normal population). In addition to aortic