An in vivo functional assay to characterize human STAT5B genetic variants during zebrafish development.

Growth hormone (GH) binding to GH receptor activates janus kinase 2 (JAK2)-signal transducer and activator of transcription 5b (STAT5b) pathway, which stimulates transcription of insulin-like growth factor-1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and insulin-like growth factor acid-labile subunit (IGFALS). Although STAT5B deficiency was established as an autosomal recessive disorder, heterozygous dominant-negative STAT5B variants have been reported in patients with less severe growth deficit and milder immune dysfunction. We developed an in vivo functional assay in zebrafish to characterize the pathogenicity of three human STAT5B variants (p.

Novel Insulin-Like Growth Factor 1 Gene Mutation: Broadening of the Phenotype and Implications for Insulin Resistance.

Context: Insulin-like growth factor (IGF)1 gene mutations are extremely rare causes of pre- and postnatal growth retardation. Phenotype can be heterogenous with varying degrees of neurosensory deafness, cognitive defects, glucose metabolism impairment and short stature.

Objective: This study describes a 12.

McCune-Albright syndrome, a rare form of precocious puberty: Diagnosis, treatment, and follow-up.

Introduction: McCune-Albright syndrome (MAS) is a genetic disorder defined by fibrous dysplasia of bone, café-au-lait skin spots, and autonomous hyperfunction of one or more endocrine organs. MAS is caused by activating mutations of the GNAS1 gene. The most frequent type of endocrinopathy is gonadal endocrinopathy in the form of peripheral precocious puberty.

Applying Bioinformatic Platforms, In Vitro, and In Vivo Functional Assays in the Characterization of Genetic Variants in the GH/IGF Pathway Affecting Growth and Development.

Heritability accounts for over 80% of adult human height, indicating that genetic variability is the main determinant of stature. The rapid technological development of Next-Generation Sequencing (NGS), particularly Whole Exome Sequencing (WES), has resulted in the characterization of several genetic conditions affecting growth and development. The greatest challenge of NGS remains the high number of candidate variants identified.

The role of acid-labile subunit (ALS) in the modulation of GH-IGF-I action.

Acid-labile subunit (ALS) deficiency (ACLSD) constitutes the first monogenic defect involving a member of the Insulin-like Growth Factor (IGF) binding protein system. The lack of ALS completely disrupts the circulating IGF system. Autocrine/paracrine action of local produced IGF-I could explain the mild effect on growth.

Expression of acid-labile subunit (ALS) in developing and adult zebrafish and its role in dorso-ventral patterning during development.

Mammalian acid-labile subunit (ALS) is a serum protein that binds binary complexes between Insulin-like growth factors (IGFs) and Insulin-like growth factor-binding proteins (IGFBPs) extending their half-life and keeping them in the vasculature. Human ALS deficiency (ACLSD), due to homozygous or compound heterozygous mutations in IGFALS, leads to moderate short stature with reduced levels of IGF-I and IGFBP-3. There is only one corresponding zebrafish ortholog gene and it has not yet been studied.

A novel heterozygous STAT5B variant in a patient with short stature and partial growth hormone insensitivity (GHI).

Background: The most frequent monogenic causes of growth hormone insensitivity (GHI) include defects in genes encoding the GH receptor itself (GHR), the signal transducer and activator of transcription (STAT5B), the insulin like-growth factor type I (IGF1) and the acid-labile subunit (IGFALS). GHI is characterized by a continuum of mild to severe post-natal growth failure.

Objective: To characterize the molecular defect in a patient with short stature and partial GHI.

p.R209H GH1 variant challenges short stature assessment.

Objective: to describe the marked variability in clinical and biochemical patterns that are associated with a p.R209H GH1 missense variant in a large Argentinean pedigree, which makes the diagnosis of GHD elusive.

Design: We describe a non-consanguineous pedigree composed by several individuals with short stature, including 2 pediatric patients with typical diagnosis of isolated growth hormone deficiency (IGHD) and 4 other siblings with severe short stature, low serum IGF-1 and IGFBP-3, but normal stimulated GH levels, suggesting growth hormone insensitivity (GHI) in the latter group.

A homozygous mutation in the highly conserved Tyr60 of the mature IGF1 peptide broadens the spectrum of IGF1 deficiency.

Background: IGF1 is a key factor in fetal and postnatal growth. To date, only three homozygous IGF1 gene defects leading to complete or partial loss of IGF1 activity have been reported in three short patients born small for gestational age. We describe the fourth patient with severe short stature presenting a novel homozygous IGF1 gene mutation.

A RECURRENT MUTATION IN TSHB GENE UNDERLYING CENTRAL CONGENITAL HYPOTHYROIDISM UNDETECTABLE IN NEONATAL SCREENING.

Objective: To describe the case of a patient with central congenital hypothyroidism (CCH) due to a recurrent mutation in the TSHB gene, as well as to conduct a genetic study of his family.

Case Description: It is presented a case report of a 5-month-old boy with a delayed diagnosis of isolated CCH in whom the molecular analysis was performed 12 years later and detected a recurrent mutation (c.373delT) in TSHB gene.

Genetic Mutations in the GH/IGF Axis.

The GH/IGF axis plays an important role in the control of pre and postnatal growth. At least 48 monogenic defects have been described affecting the production, secretion, and action of GH and IGFs. Molecular defects of the GH/IGF axis resulting in short stature were arbitrarily classified into 4 groups: 1.

Same Phenotype in Children with Growth Hormone Deficiency and Resistance.

By definition, about 2.5% of children show a short stature due to several causes. Two clinical conditions are characterized by serum IGF-I low levels, idiopathic GH deficiency (IGHD), and GH insensitivity (GHI), and the phenotypic appearance of these patients may be very similar.

Partial growth hormone insensitivity and dysregulatory immune disease associated with de novo germline activating STAT3 mutations.

Germinal heterozygous activating STAT3 mutations represent a novel monogenic defect associated with multi-organ autoimmune disease and, in some cases, severe growth retardation. By using whole-exome sequencing, we identified two novel STAT3 mutations, p.E616del and p.

Genetic disorders of GH action pathway.

While insensitivity to GH (GHI) is characterized by low IGF-I levels, normal or elevated GH levels, and lack of IGF-I response to GH treatment, IGF-I resistance is characterized by elevated IGF-I levels with normal/high GH levels. Several genetic defects are responsible for impairment of GH and IGF-I actions resulting in short stature that could affect intrauterine growth or be present in the postnatal period. The genetic defects affecting GH and/or IGF-I action can be divided into five different groups: GH insensitivity by defects affecting the GH receptor (GHR), the intracellular GH signaling pathway (STAT5B, STAT3, IKBKB, IL2RG, PIK3R1), the synthesis of insulin-like growth factors (IGF1, IGF2), the transport/bioavailability of IGFs (IGFALS, PAPPA2), and defects affecting IGF-I sensitivity (IGF1R).

Circulating IGF-I, IGFBP-3 and the IGF-I/IGFBP-3 Molar Ratio Concentration and Height Outcome in Prepubertal Short Children on rhGH Treatment over Two Years of Therapy.

Objective: To investigate the occurrence of abnormally elevated values of biomarkers of growth hormone (GH) action in short children on recombinant human GH (rhGH) therapy.

Methods: Sixty-three prepubertal short children were examined: 31 with GH deficiency (GHD), 25 small for gestational age (SGA), and 9 with Turner syndrome (TS). The main outcomes were the following: standard deviation score (SDS) values of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 molar ratio before, at the 1st and at the 2nd year on rhGH and Δheight (Ht)-SDS to evaluate GH treatment efficacy (adequate 1st-year ΔHt SDS: >0.

Characterization of four Latin American families confirms previous findings and reveals novel features of acid-labile subunit deficiency.

Objective: Acid-labile subunit deficiency (ACLSD), caused by inactivating mutations in both IGFALS gene alleles, is characterized by marked reduction in IGF-I and IGFBP-3 levels associated with mild growth retardation. The aim of this study was to expand the known phenotype and genetic characteristics of ACLSD by reporting data from four index cases and their families.

Design: Auxological data, biochemical and genetic studies were performed in four children diagnosed with ACLSD and all available relatives.

Treatment With Recombinant Human Insulin-Like Growth Factor-1 Improves Growth in Patients With PAPP-A2 Deficiency.

Context: Pregnancy-associated plasma protein-A2 (PAPP-A2) is a metalloproteinase that specifically cleaves IGFBP-3 and IGFBP-5. Mutations in the PAPP-A2 gene have recently been shown to cause postnatal growth failure in humans, with specific skeletal features, due to the resulting decrease in IGF-1 bioavailability. However, a pharmacological treatment of this entity is yet to be established.

Insulin level and insulin sensitivity indices among healthy children and adolescents.

Introduction: Information on insulin reference values and insulin sensitivity indices in the field of pediatrics is scarce.

Objective: To describe insulin range and insulin sensitivity surrogate indices during childhood.

Materials And Methods: Fasting insulin level range and surrogate indices, such as the homeostasis model assessment of insulin resistance (HOMA-IR), among healthy children and adolescents by age, body mass index, pubertal stage (PS), insulin-like growth factor-1 (IGF-1), total cholesterol, and triglycerides.

Assessment of pathogenicity of natural IGFALS gene variants by in silico bioinformatics tools and in vitro functional studies.

Acid-labile subunit (ALS) is essential for stabilization of IGF-I and IGFBP-3 in ternary complexes within the vascular system. ALS deficient (ALS-D) patients and a subset of children with idiopathic short stature (ISS), presenting IGFALS gene variants, show variable degree of growth retardation associated to IGF-I and IGFBP-3 deficiencies. The aim of this study was to evaluate the potential pathogenicity of eleven IGFALS variants identified in ALS-D and ISS children using in silico and in vitro approaches.

Mutations in pregnancy-associated plasma protein A2 cause short stature due to low IGF-I availability.

Mutations in multiple genes of the growth hormone/IGF-I axis have been identified in syndromes marked by growth failure. However, no pathogenic human mutations have been reported in the six high-affinity IGF-binding proteins (IGFBPs) or their regulators, such as the metalloproteinase pregnancy-associated plasma protein A2 (PAPP-A2) that is hypothesized to increase IGF-I bioactivity by specific proteolytic cleavage of IGFBP-3 and -5. Multiple members of two unrelated families presented with progressive growth failure, moderate microcephaly, thin long bones, mildly decreased bone density and elevated circulating total IGF-I, IGFBP-3, and -5, acid labile subunit, and IGF-II concentrations.

STAT5B mutations in heterozygous state have negative impact on height: another clue in human stature heritability.

Context And Objective: GH insensitivity with immune dysfunction caused by STAT5B mutations is an autosomal recessive condition. Heterozygous mutations in other genes involved in growth regulation were previously associated with a mild height reduction. Our objective was to assess for the first time the phenotype of heterozygous STAT5B mutations.

Heterozygous IGFALS gene variants in idiopathic short stature and normal children: impact on height and the IGF system.

Background: In acid-labile subunit (ALS)-deficient families, heterozygous carriers of IGFALS gene mutations are frequently shorter than their wild-type relatives, suggesting that IGFALS haploinsufficiency could result in short stature. We have characterized IGFALS gene variants in idiopathic short stature (ISS) and in normal children, determining their impact on height and the IGF system.

Patients And Methods: In 188 normal and 79 ISS children levels of IGF-1, IGFBP-3, ALS, ternary complex formation (TCF) and IGFALS gene sequence were determined.

Novel acid-labile subunit ( IGFALS ) mutation p.T145K (c.434C>A) in a patient with ALS deficiency, normal stature and immunological dysfunction.

We report a novel missense mutation p.T145K in the insulin-like growth factor (IGF) acid-labile subunit (IGFALS) gene identified in a Turkish patient with normal growth, transient pancytopenic episodes and signs of immunological dysfunction. Because of recurrent cutaneous mycoses and absence of pubertal development until the age of 14.