The protein BBLN with largely unknown function was identified in human right ventricular heart specimens from patients undergoing repair surgery for Tetralogy of Fallot (TOF). Proteins from heart specimens were solubilized and subjected to immuno-affinity enrichment with anti-CAMK2D-specific antibodies. Co-enriched proteins were separated by SDS-PAGE, and the protein band in the range of 8-14 kDa was cut and subjected to identification by nano-LC-ESI-MS/MS.