ESPE Abstracts

Background: ALS deficient (ALS-D) patients present severe IGFI and IGFBP3 deficiencies and variable degree of growth retardation. Heterozygous carriers for IGFALS variants, ALS-D relatives or a subset of ISS children, have levels of IGFI, IGFBP3 and ALS intermediate between ALS-D and wildtype (WT) subjects. This supports that IGFALS gene variants may affect ALS synthesis, secretion and/or function and could be responsible for the observed phenotype.<p cla...

Introduction: Complete ALS deficiency (ALS-D), caused by inactivating mutations in both IGFALS gene alleles, presents severe IGF1 and IGFBP3 deficiencies associated to moderate growth retardation.Aim: To characterize the molecular defect in a family where the index case and his father presented short stature and IGF1 and IGFBP3 deficiencies.Methods: IGF1, IGFBP3, and GH serum levels were determined by CLIA, ALS by ELISA an...

Background: Heterozygous GHR gene variants were found in 5–8% of idiopathic short stature (ISS) children. Frequent polymorphisms within GHR coding regions, but not intronic SNPs, have been investigated in ISS.Objectives: To characterize GHR gene variants in ISS children, and to test their influence on height and the peripheral GH/IGF1/IGFBPs system.Methods: GHR gene (coding/intronic flanking...

Background: Some IGFALS variants have been reported in more than one ALS-deficient family raising the question whether they originated from a single common ancestor allele (founder effect) or alternatively, as independent mutational events (hot spot). Since c.103dupG (p.E35Gfs*17) is located in a stretch of five consecutive guanine residues, where both G-duplication and deletion have been described in several families, we speculate that this region could be a hot spot...

Background: Primary IGF1 deficiency can result from molecular defects in genes encoding for the GHR, IGF1, STAT5b and ALS. Heterozygous, activating mutations in the STAT3 gene have been recently described in children with severe growth failure associated with a spectrum of early-onset autoimmune disease.Case presentation: We report the molecular diagnosis in two unrelated patients with severe growth failure and IGF1 deficiency: P1, a 3.6 year ol...

Background: Several genetic defects (GHR, SHOX, GHSR, NPR2, IGFALS) have been reported in children classified as ISS. ISS children are GH sufficient and about one third of them show low IGF-I levels, suggesting some degree of GH insensitivity.Objective: To explore potential genetic defects in ISS children suspicious of GH insensitivity, selected by low IGF-I levels and low response to IGF generation test.<...

Background: Human IGF1 gene defects are characterized by intrauterine and postnatal growth retardation, sensorineural deafness, microcephaly and intellectual disability. Seven cases have been reported so far, and the underlying pathophysiology has been characterized in only three.Objective: To describe a patient with severe short stature presenting a novel homozygous IGF1 gene mutation and its underlying pathogenic mechanism.<p clas...

Background: We have recently reported the molecular diagnosis of two patients with severe growth failure associated with a spectrum of early-onset autoimmune disease and immunodeficiency. Heterozygous de novo mutations, c.1847_1849delAAG (p.E616del) and c.1276T>C (p.C426R), in the STAT3 gene were found. Functional in vitro studies of these variants are presented.Objective and hypotheses: We...

Background: PAPP-A2 is a metalloproteinase that specifically cleaves IGFBPs 3 and 5. Papp-a2 knock-out (KO) mice show a reduction in body size and skeletal abnormalities.Objective and hypotheses: Our objective is to report two affected families from Spain and USA. The Spanish family presents a homozygous frameshift mutation in exon 3 of the PAPP-A2 gene (c.1927_ 1928insAT, p.D643fs25X) resulting in a premature stop codon, with 2 of 4 si...