DR Medhat MRCP

II. Adult polycystic kidney disease (APKD)
APKD is mainly autosomal dominant & the minority is autosomal recessive.
Autosomal dominant APKD is the most common cause of inherited kidney disease.
A) Autosomal dominant APKD
Autosomal dominant polycystic kidney disease (ADPKD) is the most common
inherited cause of kidney disease, affecting 1 in 1,000 Caucasians.
Two disease loci have been identified, PKD1 and PKD2, which code for polycystin-1
and polycystin-2 respectively.
85% of cases
ADPKD type 1
15 % of cases
ADPKD type2
Gene defect in chromosome 16 Gene defect in chromosome 4
Present with renal failure earlier
Later.
The screening investigation of choice for relatives is abdominal ultrasound
Ultrasound diagnostic criteria (in patients with positive family history)
Two cysts, unilateral or bilateral, if aged < 30 years
Two cysts in both kidneys if aged 30-59 years
Four cysts in both kidneys if aged > 60 years
B) Autosomal recessive APKD
Autosomal recessive polycystic kidney disease (ARPKD) is much less common than
autosomal dominant disease (ADPKD).
It is due to a defect in a gene located on chromosome 6
Diagnosis may be made on prenatal ultrasound or in early infancy with abdominal
masses and renal failure.
End-stage renal failure develops in childhood.
Patients also typically have liver involvement, eg portal and interlobular fibrosis
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