Original Article

Intrauterine twin discordancy followed by partial postnatal catch-up growth in a girl with a pathogenic IGF1R mutation


  • Paula Ocaranza
  • Monique Losekoot
  • Marie JE Walenkamp
  • Christiaan de Bruin
  • Jan M Wit
  • Veronica Mericq

Received Date: 26.11.2018 Accepted Date: 08.03.2019 J Clin Res Pediatr Endocrinol 0;0(0):0-0 [e-Pub] PMID: 30859796


IGF-1 is essential for normal human growth in utero and postnatally. It mediates its effects through the IGF-1 receptor (IGF1R), a widely expressed cell surface tyrosine kinase receptor.


The aim of the study was to analyze pre- and postnatal growth, clinical features and laboratory findings of discordant twins: one small for gestational age (SGA) girl and one appropriate for gestational age (AGA) brother in whom discordant postnatal growth persisted.

Patient and methods:

A girl born with a low weight and length (-2.4 SDS) but borderline low head circumference (-1.6 SD) presented with a height of -1.7 SDS, in contrast to a normal height twin brother (0.0 SDS). Because of elevated serum IGF-1 levels, IGF-1 resistance was suspected.


Sequencing revealed the presence of a previously described pathogenic heterozygous mutation (p.Glu1050Lys) in the SGA girl, not present in the parents nor the AGA twin brother.


The pathogenic IGF1R mutation in this girl led to intrauterine growth retardation followed by partial postnatal catch-up growth. Height in mid-childhood was in the lower half of the reference range, but still 1.7 SD shorter than her twin brother.

Keywords: Insulin-like growth factor type-1, Insulin-like growth factor type-1 receptor, small for gestational age, postnatal growth, intrauterine discordancy