Hereditary renal disorders

Question 1

What is the most common inherited condition affecting the kidneys?

Answer 1

Adult polycystic kidney disease

Question 2

What percentage of ADPKD is due to spontaneous mutation?

Answer 2

25%

Question 3

PKD1, a defect on chromosome 16, account for what % of cases of PKD?

Answer 3

95%

Question 4

What are the signs and symptoms of ADPKD?

Answer 4

Renal enlargement with cysts
Abdominal pain
Abdominal masses
Haematuria (haemorrhage into a cyst) and loin pain.
Cyst infection
Renal calculi
Hypertension
Progressive renal failure.

Extra-renal:
Cysts in liver, pancreas, spleen and ovaries. Rarely cause clinical problems.
Subarachnoid haemorrhage (due to berry aneurysms)
Mitral valve prolapse
Diverticular disease

Question 5

What is Alport’s syndrome characterised by?

Answer 5

Haematuria, sensorineural deafness (overt in 40%), progressive renal impairment with proteinuria in most, ocular abnormalities in 15%.

Question 6

What is the pathophysiology of Alport’s syndrome?

Answer 6

Mutation in basement membrane collagen type IV gene.
X-linked in 80%, new mutation in 20%.
Thickening and splitting of the GBM seen on renal biopsy EM.

Question 7

In Alport’s syndrome, between what ages does end stage renal failure usually develop?

Answer 7

16-35 years

Question 8

What is medullary sponge kidney?

Answer 8

Inherited disorder characterised by dilated medullary collecting ducts. Can affect both, one or part of one kidney.

Question 9

Symptoms of medullary sponge kidney?

Answer 9

Usually asymptomatic.
Small calculi may form, producing haematuria and predisposing to UTI.
Larger calculi can cause obstruction.

Note: renal failure is unusual.

Question 10

What is Von Hippel-Lindau syndrome?

Answer 10

Rare autosomal dominant disorder in which tumours affect the kidneys (renal cell carcinoma), brain (haemangioblastoma) and adrenals (phaeochromocytoma).