Controversy in clinical endocrinology - Problems with reclassification of insulin-like growth factor I production and action disorders

Context: Recent developments in the IGF field have raised questions on whether this is the right time to redefine IGF deficiency. Objective: In this controversy, arguments are made against the need for redefining IGF deficiency at this moment, suggesting instead to wait for further clinical developments. Case: Although a number of rare case reports of IGF deficiency with precise molecular etiologies have been described, the vast majority of the cases remain clinically defined and without a genetic diagnosis. Interventions: Because IGF products are now available for clinical use in IGF-deficient patients, we are still using GH stimulation and static IGF levels as our only clinical diagnostic and classification tools. Positions: We need to develop additional clinical tools, side by side with molecular tools, for the diagnosis and subclassification of IGF deficiency. Chief among these are the IGF-generation test for identification of GH-insensitive patients and genetic panels of polymorphic changes in relevant genes. Conclusions: Until further progress is made in the clinical classification of IGF deficiency, we should not change the current classification, and, when we do, it should be the responsibility of the relevant societies in the field to conduct a consensus statement on the topic first.