Here we show that mice that lack sufficient levels of one such gene, ribosomal protein S6 (Rps6) as the liver develops, fail to develop primary bile ducts resulting in disease reminiscent of North American Indian childhood cirrhosis (NAIC), a liver-specific ribosomopathy caused by mutations in a different RiBi gene, UTP4. This evidence concerns the gene RPS6 and hereditary North American Indian childhood cirrhosis.