They have been linked to the production of a smaller SMAD 4 , with missing domains that prevent the protein from binding to R - SMADS and forming heteromeric complexes .
Around 60 mutations causing JPS have been identified .
JPS have been linked to the production of a smaller SMAD 4 , with missing domains that prevent the protein from binding to R - SMADS and forming heteromeric complexes .
Around 60 mutations causing JPS have been identified .