hrp0089rfc1.3 | Adrenals & HPA Axis | ESPE2018

Sphingosine-1-Phosphate Lyase (SGPL1) Deficiency is Associated with Mitochondrial Dysfunction

Maharaj Avinaash , Bradshaw Teisha , Williams Jack , Guran Tulay , Braslavsky Debora , Brugger Britta , Metherell Lou , Prasad Rathi

Background: Loss of function mutations in SGPL1, a key component of sphingolipid metabolism, are associated with accumulation of sphingolipid intermediates giving rise to a multisystemic disease incorporating primary adrenal insufficiency (PAI) and progressive renal and neurological disease. Sphingolipids are implicated in mitochondrial apoptosis via induction of mitochondrial outer membrane permeabilization, cytosolic release of inter-membranal cytochrome c and activ...

hrp0092fc13.5 | Adrenals and HP Axis | ESPE2019

SGPL1 Deficiency Leads to Downregulation of Key Enzymes Within the Steroidogenic Pathway

Maharaj Avinaash , Meimaridou Eirini , Williams Jack , Güran Tülay , Braslavsky Debora , Metherell Louise , Prasad Rathi

Background: SGPL1 deficiency is associated with a pathological accumulation of sphingolipid intermediates and a multi-systemic condition incorporating primary adrenal insufficiency. Sphingolipid intermediates such as ceramide, sphingosine and sphingosine 1-phosphate are postulated to act as modulators of the steroidogenic pathway, often acting as second messengers altering downstream expression of steroid responsive transcriptional elements. Ceramide and sphin...

hrp0094p1-179 | Growth Hormone and IGFs B | ESPE2021

Novel dominant negative GH receptor variants provide important insights into GH receptor physiology

Andrews Afiya , Cottrell Emily , Maharaj Avinaash , Ladha Tasneem , Williams Jack , Metherell Louise A , McCormick Peter J , Storr Helen L ,

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...

hrp0095p1-101 | GH and IGFs | ESPE2022

A rare heterozygous IGFI variant causing impaired IGF-I cleavage and postnatal growth failure: a novel disease mechanism with insights into IGF-I physiology

Cottrell Emily , Andrews Afiya , Williams Jack , Chatterjee Sumana , Edate Sujata , A. Metherell Louise , Hwa Vivian , L. Storr Helen

Background: Pathogenic IGFI gene mutations causing childhood growth failure are rare. Only 5 autosomal recessive mutations, one IGFI copy number variant and 2 heterozygous frameshift mutations are reported. Heterozygous missense IGFI mutations have not previously been described.Objectives: To identify and functionally characterise a novel missense IGFI variant in a patient with postnat...

hrp0092rfc14.4 | Adrenals and HP Axis | ESPE2019

GHR Transcript Heterogeneity May Explain the Phenotypic Variability in Patients with Homozygous GHR Pseudoexon (6ψ) Mutation

Chatterjee Sumana , Rose Steven J , Mushtaq Talat , Cottrell Emily , Maharaj Avinaash V , Williams Jack , Savage Martin O , Metherell Loiuse A , Storr Helen L

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...

hrp0094p2-287 | Growth and syndromes (to include Turner syndrome) | ESPE2021

Novel LZTR1 mutations in subjects with features of Noonan Syndrome and GH insensitivity negatively regulate GH-induced IGF-I production and hyperactivate GH-induced ERK1/2 activation in response to GH in vitro

Chatterjee Sumana , Romeo Bertola Debora , Agwu Chizo , Maharaj Avinaash , Williams Jack , Cottrell Emily , Shapiro Lucy , Andrews Afiya , Savage Martin O. , Gaston-Massuet Carles , Metherell Louise A. , Storr Helen L. ,

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...

hrp0095p1-110 | Growth and Syndromes | ESPE2022

Characterisation of the first heterozygous missense HMGA2 variant helps delineate the crucial functional roles of a novel growth gene

Cottrell Emily , V. Maharaj Avinaash , Triggs-Raine Barbara , Thanasupawat Thatchawan , Williams Jack , Fujimoto Masanobu , A. Metherell Louise , Hwa Vivian , Klonisch Thomas , Hombach-Klonisch Sabine , L. Storr Helen

Background: Silver Russell syndrome (SRS) is genetically heterogenous and around 30% of patients with clinical SRS have no genetic diagnosis. Mutations in HMGA2 have recently been identified causing growth failure and an SRS-like phenotype. Despite strong evidence of the crucial role of HMGA2 in growth across species, the mechanism of action of HMGA2 in human linear growth is unclear.Objective:...

hrp0094p1-173 | Growth Hormone and IGFs B | ESPE2021

Growth hormone receptor 6Ω pseudoexon activation: a novel cause of severe growth hormone insensitivity

Cottrell Emily , Maharaj Avinaash , Williams Jack , Chatterjee Sumana , Cirillo Grazia , Giudice Emanuele Miraglia del , Festa Adalgisa , Palumbo Stefania , Capalbo Donatella , Salerno Mariacarolina , Pignata Claudio , Savage Martin O. , Schilbach Katharina , Bidlingmaier Martin , Hwa Vivian , Metherell Louise A. , Grandone Anna , Storr Helen L. ,

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 ...