A Heterozygous Mutation of the Insulin-Like Growth Factor-I Receptor Causes Retention of the Nascent Protein in the Endoplasmic Reticulum and Results in Intrauterine and Postnatal Growth Retardation

Abstract

The V599E-IGF1R mutation interferes with the receptor's trafficking path, thereby abrogating proreceptor processing and plasma membrane localization. Diminished cell surface receptor density solely expressed from the patient's wild-type allele is supposed to lead to insufficient IGF-I signaling. We hypothesize that this mechanism results in intrauterine and postnatal growth retardation of the affected patient. The reported retention of the nascent IGF1R in the endoplasmic reticulum presents a novel mechanism of IGF-I resistance.