A new p.(Ile66Serfs*93) IGF2 variant is associated with pre- and postnatal growth retardation

in European Journal of Endocrinology
Correspondence should be addressed to D Rockstroh; Email: Denise.Rockstroh@medizin.uni-leipzig.de
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The IGF/IGF1R axis is involved in the regulation of human growth. Both IGF1 and IGF2 can bind to the IGF1R in order to promote growth via the downstream PI3K/AKT pathway. Pathogenic mutations in IGF1 and IGF1R determine intrauterine growth restriction and affect postnatal body growth. However, to date, there are only few reports of pathogenic IGF2 mutations causing severe prenatal, as well as postnatal growth retardation.


Here we describe a de novo c.195delC IGF2 variant (NM_000612, p.(Ile66Serfs*93)) in a 4-year-old patient with severe pre- and post-natal growth retardation in combination with dystrophy, facial dimorphism, finger deformities, as well as a patent ductus. Cloning and sequencing of a long-range PCR product harboring the deletion and a SNP informative site chr11:2153634 (rs680, NC_000011.9:g.2153634T>C) demonstrated that the variant resided on the paternal allele. This finding is consistent with the known maternal imprinting of IGF2. 3D protein structure prediction and overexpression studies demonstrated that the p.(Ile66Serfs*93) IGF2 gene variation resulted in an altered protein structure that impaired ligand/receptor binding and thus prevents IGF1R activation.


The severity of the phenotype in combination with the dominant mode of transmission provides further evidence for the involvement of IGF2 in growth disorders.


Official journal of

European Society of Endocrinology



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    Pedigree, growth curve and clinical characteristics of the patient. (A) The index patient (III.2) bearing the heterozygous p.(Ile66Serfs*93) variation is indicated by a half-filled symbol and marked by an arrow. Height (cm) and standard deviation score (SDS) of the last reported visit is shown below the symbol. Crossed out lines indicate half siblings (n.a., no data available). Growth curve of the index patient (B) indicated a severe growth failure. Bone age is shown by a gray square, while initiation of rhGH therapy is shown by a gray arrow. White circles indicated patients’ height adjusted for week of pregnancy, while black circles indicate unadjusted values. (C) Clinical features of the index patient: short stature (I, II), triangular face (III), low-set ears (IV, V), frontal bossing (V) and a clinodactyly (VI–VIII marked by an arrow).

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    Identification of a novel p.(Ile66Serfs*93) IGF2 variation. (A) Electropherograms of Sanger sequencing analyses. Arrow, position of the c.195delC deletion; *frameshift of the aa sequence. (B) Structure of the IGF2 protein. Normal protein translation generates a 180-aa IGF2 precursor protein. The I66S variation is predicted to results in a frameshift (position 66) in combination with a premature stop codon at position 93. The changed aa sequence in the mutant beginning from position 66 is shown in italics. (C) Schematic illustration of so far identified IGF2 mutations (9, 11, 12). IGF2 encode an inactive 180-aa (Isoform 1, NP_000603) or 236-aa (Isoform 2, NP_001121070) precursor protein that includes a 24-aa signal peptide (SP), a 67-aa core IGF2 and a 89-aa trailer sequence (18). The p.I66S variation is localized in the core-IGF2 sequence of isoform 1 (NM_000612).

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    Illustration of potential conformational changes in p.I66S protein structure. (A) Schematic diagram of IGF2 maturation. IGF2 encodes an inactive 180-aa precursor protein which is post-translationally cleaved into a 67-aa bioactive protein. First, the terminal signal peptide is proteolytically removed creating a 156-aa sequence. In the next step, the trailer sequence is proteolytically cleaved at two separated sites (TQRLRR 104 and PAKSER 68) generating the bioactive protein. (B) Illustration of p.I66S protein structure. Sequence analyses of the cleavage sites indicated a changed aa sequence at basic residues in the mutant: TQRLRR→PSACAG and PAKSER→PPSPRG. (C) Comparison of the WT (IGF2-WT, blue) and mutant (IGF2-I66S, red) protein structure. 3D protein structure was predicted based on the crystal structure of IGF2-WT (pdb: 1IGL) using the iTASSER server and superpositioned with the WT structure. The mostly unstructured C-terminal extension due to the lack of posttranslational processing is illustrated. (D) Upper panel: Schematic presentation of IGF2 plasmids. The position of the c.195delC mutation is marked in red. Lower panel: Cell lysates and supernatants from transfected cells after immunoblotting with the indicated antibodies. (E) Whole-cell lysates from IGF1 stimulated (30 min) cells transfected with an IGF1R plasmid were subjected to immunoblotting using antibodies as indicated. (F) Whole-cell lysates were prepared from IGF1R transfected cells after stimulation (30 min) with IGF2-WT supernatants and immunoblotted for pIGF1R, total IGF1R and β-actin as loading control. Representative blot out of three independent experiments is shown.

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    The p.I66S variant inhibits IGF1R activation. (A) Immunoblots of untreated or rhIGF1 treated (30 min, 10 nM) cell lysates after co-transfection with IGF1R and IGF2 constructs were analyzed using the antibodies as indicated. In addition, supernatants from every approach were analyzed using an IGF2 antibody. (B) Densitometric evaluation of IGF1R activation (fold change of the variant compared to empty vector). pIGF1R levels were normalized to total IGF1R and β-actin protein amounts and results are shown as mean ± s.e.m. Significant P-values are indicated. ***P < 0.001. (C) Cell lysates or supernatant from IGF1R transfected cells after stimulation with IGF2 supernatants (30 min) analyzed with the indicated antibodies. (D) Densitometric evaluation of IGF1R activation (fold change of the variants compared to an empty vector control). *P < 0.05, **P < 0.01. (E) Illustration of IGF2 residues interacting with domains of the IGF1 receptor according to Vashisth et al. (20). L1 residues are shown in red, CR residues in green, L2 residues in blue, and (F1–F2)′ residues are shown in yellow. The IGF2 variant lacks L1, L2 and (F1–F2)′ residues (highlighted in bold). (F) Rescue experiment with the p.I66S variation. Lysates of IGF1R/IGF2 co-transfected HEK293 cells after stimulation with recombinant IGF1 (30 min, 10 nM) in comparison to unstimulated approaches. For each approach a representative Western blot out of three independent experiments is shown.



LeRoithDYakarS. Mechanisms of disease: metabolic effects of growth hormone and insulin-like growth factor 1. Nature Clinical Practice Endocrinology and Metabolism 2007 3 302310. (https://doi.org/10.1038/ncpendmebib427)


BaxterRC. Insulin-like growth factor (IGF)-binding proteins: interactions with IGFs and intrinsic bioactivities. American Journal of Physiology: Endocrinology and Metabolism 2000 278 E967E976. (https://doi.org/10.1152/ajpendo.2000.278.6.E967)


EngströmWShokraiAOtteKGranérusMGessboABierkePMadejASjölundMWardA. Transcriptional regulation and biological significance of the insulin like growth factor II gene. Cell Proliferation 1998 31 173189. (https://doi.org/10.1111/j.1365-2184.1998.tb01196.x)


BergmanDHaljeMNordinMEngströmW. Insulin-like growth factor 2 in development and disease: a mini-review. Gerontology 2013 59 240249. (https://doi.org/10.1159/000343995)


DeChiaraTMRobertsonEJEfstratiadisA. Parental imprinting of the mouse insulin-like growth factor II gene. Cell 1991 64 849859. (https://doi.org/10.1016/0092-8674(91)90513-X)


DemarsJGicquelC. Epigenetic and genetic disturbance of the imprinted 11p15 region in Beckwith-Wiedemann and Silver-Russell syndromes. Clinical Genetics 2012 81 350361. (https://doi.org/10.1111/j.1399-0004.2011.01822.x)


GicquelCRossignolSCabrolSHouangMSteunouVBarbuVDantonFThibaudNLe MerrerMBurglenL Epimutation of the telomeric imprinting center region on chromosome 11p15 in Silver-Russell syndrome. Nature Genetics 2005 37 10031007. (https://doi.org/10.1038/ng1629)


SaalHM. Russell-Silver syndrome. In GeneReviews. Seattle: University of Washington1993.


BegemannMZirnBSantenGWirthgenESoellnerLBüttelHMSchweizerRvan WorkumWBinderGEggermannT. Paternally inherited IGF2 mutation and growth restriction. New England Journal of Medicine 2015 373 349356. (https://doi.org/10.1056/NEJMoa1415227)


Abi HabibWBrioudeFEdouardTBennettJTLienhardt-RoussieATixierFSalemJYuenTAzziSLe BoucY Genetic disruption of the oncogenic HMGA2-PLAG1-IGF2 pathway causes fetal growth restriction. Genetics in Medicine 2018 20 250258. (https://doi.org/10.1038/gim.2017.105)


YamotoKSaitsuHNakagawaNNakajimaHHasegawaTFujisawaYKagamiMFukamiMOgataT. De novo IGF2 mutation on the paternal allele in a patient with Silver-Russell syndrome and ectrodactyly. Human Mutation 2017 38 953958. (https://doi.org/10.1002/humu.23253)


LiuDWangYYangXALiuD. De novo mutation of paternal IGF2 gene causing Silver–Russell syndrome in a sporadic patient. Frontiers in Genetics 2017 8 105. (https://doi.org/10.3389/fgene.2017.00105)


MelchersPPreussU. Revision of the Kaufman assessment battery for children for German speaking regions. Part 2: areas of application and criteria of reliability. Zeitschrift fur Kinder- und Jugendpsychiatrie 1992 20 223231.


BlumWFRankeMBBierichJR. A specific radioimmunoassay for insulin-like growth factor II: the interference of IGF binding proteins can be blocked by excess IGF-I. Acta Endocrinologica 1988 118 374380. (https://doi.org/10.1530/acta.0.1180374)


ZhangY. I-TASSER server for protein 3D structure prediction. BMC Bioinformatics 2008 9 40. (https://doi.org/10.1186/1471-2105-9-40)


DransfieldDTCohenEHChangQSparrowLGBentleyJDDolezalOXiaoXPeatTSNewmanJPillingPA A human monoclonal antibody against insulin-like growth factor-II blocks the growth of human hepatocellular carcinoma cell lines in vitro and in vivo. Molecular Cancer Therapeutics 2010 9 18091819. (https://doi.org/10.1158/1535-7163.MCT-09-1134)


WakelingELBrioudeFLokulo-SodipeOO’ConnellSMSalemJBliekJCantonAPMChrzanowskaKHDaviesJHDiasRP Diagnosis and management of Silver-Russell syndrome: first international consensus statement. Nature Reviews Endocrinology 2017 13 105124. (https://doi.org/10.1038/nrendo.2016.138)


Pagter-Holthuizen PdeHöppenerJWJansenMGeurts van KesselAHvan OmmenGJSussenbachJS. Chromosomal localization and preliminary characterization of the human gene encoding insulin-like growth factor II. Human Genetics 1985 69 170173. (https://doi.org/10.1007/BF00293291)


QiuQBasakAMbikayMTsangBKGruslinA. Role of pro-IGF-II processing by proprotein convertase 4 in human placental development. PNAS 2005 102 1104711052. (https://doi.org/10.1073/pnas.0502357102)


VashisthHAbramsCF. All-atom structural models for complexes of insulin-like growth factors IGF1 and IGF2 with their cognate receptor. Journal of Molecular Biology 2010 400 645658. (https://doi.org/10.1016/j.jmb.2010.05.025)


LiuJPBakerJPerkinsASRobertsonEJEfstratiadisA. Mice carrying null mutations of the genes encoding insulin-like growth factor I (Igf-1) and type 1 IGF receptor (Igf1r). Cell 1993 75 5972.


Powell-BraxtonLHollingsheadPWarburtonCDowdMPitts-MeekSDaltonDGillettNStewartTA. IGF-I is required for normal embryonic growth in mice. Genes and Development 1993 7 26092617. (https://doi.org/10.1101/gad.7.12b.2609)


NetchineIAzziSLe BoucYSavageMO. IGF1 molecular anomalies demonstrate its critical role in fetal, postnatal growth and brain development. Best Practice and Research Clinical Endocrinology and Metabolism 2011 25 181190. (https://doi.org/10.1016/j.beem.2010.08.005)


DeChiaraTMEfstratiadisARobertsenEJ. A growth-deficiency phenotype in heterozygous mice carrying an insulin-like growth factor II gene disrupted by targeting. Nature 1990 345 7880. (https://doi.org/10.1038/345078a0)


VerhaegheJVan BreeRVan HerckELaureysJBouillonRVan AsscheFA. C-peptide, insulin-like growth factors I and II, and insulin-like growth factor binding protein-1 in umbilical cord serum: correlations with birth weight. American Journal of Obstetrics and Gynecology 1993 169 8997. (https://doi.org/10.1016/0002-9378(93)90137-8)


ConstânciaMHembergerMHughesJDeanWFerguson-SmithAFundeleRStewartFKelseyGFowdenASibleyC Placental-specific IGF-II is a major modulator of placental and fetal growth. Nature 2002 417 945948. (https://doi.org/10.1038/nature00819)


ClemmonsDR. Insulin-like growth factor binding proteins and their role in controlling IGF actions. Cytokine and Growth Factor Reviews 1997 8 4562. (https://doi.org/10.1016/S1359-6101(96)00053-6)


BaxterRCMartinJL. Binding proteins for the insulin-like growth factors: structure, regulation and function. Progress in Growth Factor Research 1989 1 4968. (https://doi.org/10.1016/0955-2235(89)90041-0)


QiuQYanXBellMDiJTsangBKGruslinA. Mature IGF-II prevents the formation of ‘big’ IGF-II/IGFBP-2 complex in the human circulation. Growth Hormone and IGF Research 2010 20 110117. (https://doi.org/10.1016/j.ghir.2009.11.001)


HodgkinsonSCDavisSRMooreLGHendersonHVGluckmanPD. Metabolic clearance of insulin-like growth factor-II in sheep. Journal of Endocrinology 1989 123 461468. (https://doi.org/10.1677/joe.0.1230461)


LivingstoneCBoraiA. Insulin-like growth factor-II: its role in metabolic and endocrine disease. Clinical Endocrinology 2014 80 773781. (https://doi.org/10.1111/cen.12446)


DaughadayWHTrivediBBaxterRC. Serum ‘big insulin-like growth factor II’; from patients with tumor hypoglycemia lacks normal E-domain O-linked glycosylation, a possible determinant of normal propeptide processing. PNAS 1993 90 58235827. (https://doi.org/10.1073/pnas.90.12.5823)


AlvinoCLMcNeilKAOngSCDelaineCBookerGWWallaceJCWhittakerJForbesBE. A novel approach to identify two distinct receptor binding surfaces of insulin-like growth factor II. Journal of Biological Chemistry 2009 284 76567664. (https://doi.org/10.1074/jbc.M808061200)


GodfreyKMBarkerDJ. Fetal programming and adult health. Public Health Nutrition 2001 4 611624. (https://doi.org/10.1079/PHN2001145)


LupuFTerwilligerJDLeeKSegreGVEfstratiadisA. Roles of growth hormone and insulin-like growth factor 1 in mouse postnatal growth. Developmental Biology 2001 229 141162. (https://doi.org/10.1006/dbio.2000.9975)


WuSYangWDe LucaF. Insulin-like growth factor-independent effects of growth hormone on growth plate chondrogenesis and longitudinal bone growth. Endocrinology 2015 156 25412551. (https://doi.org/10.1210/en.2014-1983)


EkströmTJCuiHLiXOhlssonR. Promoter-specific IGF2 imprinting status and its plasticity during human liver development. Development 1995 121 309316.


EkströmTJCuiHNyströmARutanenEMOhlssonR. Monoallelic expression of IGF2 at the human fetal/maternal boundary. Molecular Reproduction and Development 1995 41 177183. (https://doi.org/10.1002/mrd.1080410208)

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