GCG and Hermansky-Pudlak syndrome: The ability to demonstrate change over time in the QoL in individuals receiving HPS treatment is, of course, relevant to the use of therapies that may reduce HPS requirements [45,46], such as surgical restoration of bowel continuity (bringing colon or distal bowel back into circuit) [47,48,49], intestinal lengthening [50], or treatment with entero-hormones such as glucagon-like peptide-2 analogues [51].