Autosomal dominant polycystic kidney disease (ADPKD) is characterized by cyst formation throughout the kidney parenchyma. It is caused by mutations in either of two genes, PKD1 and PKD2. Mice that lack functional Pkd1 (Pkd1null/null), develop rapidly progressive cystic disease during embryogenesis, and serve as a model to study human ADPKD. We examined the molecular pathways that modulate renal cyst growth in the Pkd1null/null model by performing global gene-expression proling in embryonic kidneys at day 14 and 17. Gene Ontology and gene set enrichment analysis were used to identify overrepresented signaling pathways in Pkd1null/null kidneys. We found dysregulation of developmental, metabolic, and signaling pathways (e.g. Wnt, calcium, TGF-b and MAPK) in Pkd1null/null kidneys.