[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Urogenital system](https://durgical.com/en/embryology/#a-urogenital) › Multicystic dysplastic kidney and polycystic kidney disease [Embryology](https://durgical.com/en/embryology/) · [Urogenital system](https://durgical.com/en/embryology/#a-urogenital) # Multicystic dysplastic kidney and polycystic kidney disease - Malformation Kidneys full of cysts for two different reasons: a kidney that never formed properly, or a genetic defect of the tubule cells. Updated 2026-11-01 **See it in 3D:** [Kidneys](https://durgical.com/en/anatomy/kidney/) ## Key points - Multicystic dysplastic: unilateral, non-functioning, cysts of varying size that do not connect; atretic ureter. - If bilateral, it behaves like agenesis: oligohydramnios and Potter sequence. - Autosomal recessive PKD (PKHD1, fibrocystin): large echogenic kidneys at birth, with congenital hepatic fibrosis. - Autosomal dominant PKD (PKD1 on chromosome 16, PKD2 on chromosome 4): adult onset, liver cysts, brain aneurysms. - Both polycystic diseases are ciliopathies: proteins of the tubule's primary cilium fail. - The kidney opposite a multicystic kidney often has reflux or UPJ obstruction. ## What it is A multicystic dysplastic kidney never developed because the dialogue between ureteric bud and blastema failed: what remains is a non-functioning cluster of cysts, almost always on one side. Polycystic kidney disease is inherited: the autosomal recessive form shows at birth and the dominant form in adulthood. Telling them apart on prenatal ultrasound changes the outlook completely. ## Embryological cause - Multicystic dysplastic: the ureteric bud fails (often with ureteral atresia) and does not induce normal nephrons; the blastema forms cysts and dysplastic tissue. - It is linked to disturbances of the GDNF–RET pathway that guides bud branching. - Polycystic: nephrons form, but a defect in primary cilium proteins (polycystins, fibrocystin) disturbs proliferation and secretion of the tubular epithelium. - In the recessive form the collecting ducts dilate radially; in the dominant form cysts arise from any nephron segment and grow over the years. ## Markers - PKD1 - PKD2 - PKHD1 - GDNF - RET ## How it presents - Multicystic: an abdominal mass in the newborn or a prenatal finding; many involute over time. - Recessive: oligohydramnios, pulmonary hypoplasia, palpable kidneys, hypertension and early renal failure; portal hypertension from hepatic fibrosis. - Dominant: flank pain, haematuria, hypertension, infections, stones and progression to chronic kidney disease. - Dominant: liver cysts, mitral valve prolapse and intracranial aneurysms. ## Diagnosis - Prenatal ultrasound: large non-communicating cysts without normal parenchyma (multicystic) versus enlarged, hyperechoic kidneys (recessive). - Renal scintigraphy: the multicystic kidney shows no uptake. - Ultrasound and cystography of the other kidney in multicystic disease. - Genetic testing and ultrasound of relatives for the dominant form. ## Memory aid “A bunch of grapes on one side: dysplastic; two sponge kidneys: recessive; cysts that grow up with their owner: dominant.” ## Test yourself Think of the answer, then tap the question to see it. ## What is the embryological cause of a multicystic dysplastic kidney? Failure of the ureteric bud, often with ureteral atresia, so normal nephrons are not induced; the blastema forms cysts and dysplastic tissue. ## Which gene is altered in autosomal recessive PKD, and which liver lesion goes with it? PKHD1 (fibrocystin); it goes with congenital hepatic fibrosis. ## What are the extrarenal complications of autosomal dominant PKD? Liver cysts, intracranial aneurysms and mitral valve prolapse, among others. ## Why is the other kidney examined in a child with a multicystic kidney? It often has vesicoureteral reflux or UPJ obstruction, and it is the only working kidney. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/embryology/multicystic-dysplastic-kidney-and-polycystic-kidney-disease/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Kidneys](https://durgical.com/en/anatomy/kidney/) ## Related - [Kidney: pronephros, mesonephros, metanephros and ascent](https://durgical.com/en/embryology/kidney-pronephros-mesonephros-metanephros-and-ascent/) - [Renal agenesis and the Potter sequence](https://durgical.com/en/embryology/renal-agenesis-and-the-potter-sequence/) - [Duplicated ureter, UPJ obstruction and posterior urethral valves](https://durgical.com/en/embryology/duplicated-ureter-upj-obstruction-and-posterior-urethral-valves/) - [Amniotic fluid: polyhydramnios and oligohydramnios](https://durgical.com/en/embryology/amniotic-fluid-polyhydramnios-and-oligohydramnios/) - [Pulmonary hypoplasia](https://durgical.com/en/embryology/pulmonary-hypoplasia/) - [Biliary atresia](https://durgical.com/en/embryology/biliary-atresia/) ## Related conditions - [Autosomal dominant polycystic kidney disease](https://durgical.com/en/conditions/autosomal-dominant-polycystic-kidney-disease/) - [Chronic kidney disease](https://durgical.com/en/conditions/chronic-kidney-disease/) [← All of embryology](https://durgical.com/en/embryology/) Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given. Sources: [Polycystic kidney disease: MedlinePlus Genetics](https://medlineplus.gov/genetics/condition/polycystic-kidney-disease/) (MedlinePlus, U.S. National Library of Medicine, 2024); [Embryology, Kidney, Bladder, and Ureter - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK547747/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Embryology, Genitourinary - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK559309/) (StatPearls Publishing (NCBI Bookshelf), 2023). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/embryology/multicystic-dysplastic-kidney-and-polycystic-kidney-disease/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/multicystic-dysplastic-kidney-and-polycystic-kidney-disease/