Dominant inheritance of large molecular weight species of glucagon

Excessive plasma levels of high molecular weight (MW) components of immunoreactive glucagon (IRG) have been found in three generations of a family in a pattern consistent with an autosomal dominant trait. Preliminary studies using gel filtration suggest the presence of two MW species of IRG greater than 3500 daltons in plasma of affected members who have normal oral glucose tolerance tests. The "hyperglucagonemia" in this pedigree is consonant with either a structural defect in biosynthetic precursors or an abnormality in enzyme-mediated cleavage of proglucagon.