ENG and hereditary hemorrhagic telangiectasia: Reports over homozygous inheritance for this disease process have been controversial, rare, and thought to be incompatible with life.1 There have been over 100 mutations reported for 3 genes responsible for causing the disease.1 There are 5 genetic subtypes of HHT, 3 of which have been linked to specific genes (see Table 2).2 The endoglin gene located on chromosome 9q is responsible for HHT-1 subtype.