In addition, IGF1R copy number variants can cause prenatal and postnatal growth restriction or overgrowth.43 However, IGF-1 insensitivity may also be related to mutation downstream of the IGF-1 receptor or by defective micro-RNA regulation of IGF-1 signalling.11,44 This condition may also be associated with other diseases such as cardiac defects and impaired glucose tolerance.45,46. Here, IGF1 is linked to Impaired glucose tolerance.