The presence of two BMP10 paralogs in zebrafish allowed for later assessment of juvenile and postnatal phenotypes; surprisingly, whereas bmp10-like mutants develop no phenotype, bmp10 mutants display vascular malformation in the skin and liver and high-output heart failure, with variable age of onset, penetrance, and expressivity (90), reminiscent of HHT. Here, BMP10 is linked to heart failure.