ESPE Abstracts

Background: Certain genetic defects in the growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis are associated with severe primary IGF-1 deficiency (SPIGFD) and short stature. Detection of genetic defects may confirm short stature aetiology alongside clinical/biochemical features. Increlex® is a recombinant human IGF-1 (rhIGF-1) approved for children/adolescents with SPIGFD.Methods: The Increlex<...

Background: Growth Hormone Insensitivity (GHI) is usually caused by mutations in the Growth Hormone receptor (GHR). Patients present with short stature associated with high GH and low IGF-I levels and often have midfacial hypoplasia (typical Laron syndrome facial features). Our centre previously described the first GHR pseudoexon mutation (42700896A>G, c. 618+792A>G). The inclusion of this 108bp pseudoexon is predicted to lead to in-frame insertion of...

Background: Growth hormone insensitivity (GHI) encompasses normal/elevated growth hormone (GH), low IGF-I levels and growth restriction. Non-classical/mild-moderate GHI is an emerging entity which is poorly characterised, and, in many subjects, the underlying cause is unclear. Heterozygous dominant negative (DN) variants located in the intracellular/transmembrane domain of the GH receptor (GHR) cause a ‘non-classical’ GHI phenotype.<p class="abst...

Objectives: The homozygous GHR pseudoexon (6ψ) mutation leads to aberrant splicing of the GHR gene with clinical and biochemical heterogeneity. We investigated whether the phenotypic variability could be explained by transcript heterogeneity i.e. ratio of abnormal (6ψ GHR) to normal (WT GHR) transcripts and/or the presence of concurrent defects in other short stature (SS) genes.Methods: 6&#968...

Triple A syndrome (AAAS) is a rare, incurable, recessive disorder, characterised by achalasia, alacrima, adrenal failure and a neurodegenerative phenotype. The AAAS gene encodes ALADIN, is a nuclear pore complex (NPC) protein necessary for nuclear import of DNA protective molecules, important for redox homeostasis. ALADIN’s role is not fully characterised: its discovery at the centrosome and the endoplasmic reticulum suggests a role outside the NPC. To date, the ...

Background: The Low dose dexamethasone suppression test (LDDST) is an important investigation for suspected Cushing’s Syndrome (CS). The traditional definition of normal suppression of serum cortisol to ≤50 nmol/l during the LDDST (0.5 mg 6 hrly × 48 h) comes from a time when biochemical autoanalysers did not routinely detect very low values. Previous studies reported 5.1–8.3% of patients with Cushing’s Disease (CD) suppressed to <50 nmol/l at 48 ...

Background: Noonan Syndrome (NS) can overlap clinically and biochemically with growth hormone insensitivity [GHI; short stature (SS), low IGF-I and normal/elevated GH levels]. Mutations in multiple genes regulating RAS/MAPK pathway have been identified in NS including LZTR1 variants. Function of LZTR1 is poorly understood and its role in growth retardation is unknown.Objectives: To functionally characte...

Introduction: Our Centre is an international referral centre for genetic analysis of children with short stature (SS) and features of GH/IGF-1 resistance. Following candidate gene and whole exome sequencing, diagnoses for ~50% patients remained elusive. Copy number variation (CNV) has not previously been investigated in GH/IGF-1 resistance and we hypothesised that CNVs contribute to the phenotype in our undiagnosed cohort.Experimental Design and Methodol...

Context: Severe forms of growth hormone insensitivity (GHI) are characterised by extreme short stature, dysmorphism and metabolic anomalies. They are classically caused by homozygous or compound heterozygous mutations of the growth hormone receptor gene (GHR). Genetic analysis traditionally focuses on the exonic regions of genes that encode proteins rather than the intervening non-coding sequences. These seldom explored non-coding regions may harbour ...