• Genetic/Hereditary Renal Disease

    by  • 28/04/2013 • Renal • 0 Comments

    Autosomal dominant polycystic kidney disease (APKD)

    1. Variety of inherited conditions affecting kidney – but adult polycystic kidney disease (APKD) is most common
    2. Accounts for 8-10% of patients with end stage renal failure
    3. Autosomal dominant inheritance: chromosome 16 (PKD1 gene in 95% of cases), or C14 PKD2 in 5%.
    4. Typically presents in adulthood
    5. Characterised by progressive appearance and enlarging renal cysts – these may bleed, become infected. As cysts enlarge – renal function deteriorates. Patients may present with abdo masses, HTN (>75%), MVP (>25%), chronic renal failure, SAH in 10% due to associated beri aneurysms!!!
    6. Cysts can also occur in liver, pancreas, spleen, ovaries.
    7. Ix: USS, CT, renal function by serum creatinine and creatinine clearance. Exclude UTI.
    8. Mx: control HTN, if infection = Abx, if pain = analgesia, as disease progresses = dialysis, then finally transplant. Genetic counselling is important in >18yo’s.

     

    Simple cysts:

    1. Occur with ageing – >12% of popn >50yo will have cyst(s).
    2. Usually asymptomatic and detected incidentally
    3. Important to distinguish from multiple cysts of APKD, other cystic diseases and renal cell carcinoma
    4. On USS = smooth walls and no intracystic debris. If doubt = CT scan.

     

    Alport’s syndrome:

    1. Haematuria, sensorineural deafness (overt in 40%), progressive renal impairment with proteinuria and eye/ocular abnormalities in 15%
    2. Caused by mutation in basement membrane type IV collagen gene (=COL4A5).
    3. X-linked in 80% (=creating a more severe phenotype in men)
    1. Ix: renal biopsy = thickening and splitting of glomerular basement membrane on electron microscopy
    2. End stage renal failure (ie disease requiring dialsysis) develops between 16-35 years of age in virtually all males with X-linked Alport’s syndrome.
    3. Mx: transplantation can result in a Goodpastures disease-like syndrome caused by the immunological reaction to the unseen type IV collagen from the transplanted kidney

     

    Medullary sponge kidney:

    1. Dilated medullary collecting ducts and can affect both or just one kidney
    2. Asymptomatic
    3. Small calculi can form resulting in haematuria and predispose to UTI/obstruction.
    4. Ix: Intravenous urogram (IVU) = shows a ‘blush-like’ opacity in medulla corresponding to accumulation of contrast in dilated collecting ducts

     

    Tuberous sclerosis:

    1. Rare (1/100,000), autosomal dominant
    2. Tumour like malformations (=hamartomas) develop in CNS (=learning disorders and epilepsy) and also skin lesions including facial angiofibromas and hypomelanotic macules and kidneys can develop angiomyolipomas, cysts and malignancies.

     

    Von Hippel-Lindau syndrome

    1. Very rare, autosomal dominant
    2. Tumours affecting kidneys (=renal cell carcinoma), brain (=haemangioblastomas), adrenals (=phaechromocytoma)
    3. Mutations in VHL gene also seen in patients with sporadic renal cell carcimonas

     

    Anderson-Fabry disease:

    1. X-linked recessive
    2. Mutations to gene encoding alpha-galactosidase A (=accumulation of intracellular glycosphinolipids) = progressive renal failure, autonomic dysfunction and skin lesions (=’angiokeratomas’ = dark red macules).
    3. Diagnosis confirmed by reduced urinary alpha-galactosidase A 
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