Endocrine Abstracts

Familial glucocorticoid deficiency (FGD, OMIM#202200) is a rare autosomal recessive disorder characterised by adrenal resistance to the action of ACTH, with isolated glucocorticoid deficiency. Recently, mutations in NNT, encoding the mitochondrial anti-oxidant nicotinamide nucleotide transhydrogenase have been reported to cause FGD.Our index case, from a highly consanguineous Kashmiri family, was diagnosed with adrenal insufficiency during a sep...

Familial glucocorticoid deficiency (FGD) is a rare autosomal recessive disorder characterised by unresponsiveness to ACTH and isolated cortisol deficiency. FGD is caused by mutations in genes encoding the ACTH receptor (melanocortin 2 receptor (MC2R)), its accessory protein (MRAP) or the steroidogenic acute regulatory protein (StAR). One significant feature is generalized skin hyperpigmentation which is thought to be due to elevated ACTH acting on the melanocortin 1 receptor (...

Background: The identification of MRAP in 2005 as the first melanocortin-2-receptor (MC2R)/ACTH receptor accessory protein provided insight into the regulation of the melanocortin receptor system. Mutations in MRAP cause Familial glucocorticoid deficiency, an autosomal recessive disorder resulting in isolated cortisol deficiency. In vitro studies showed that MRAP was essential for the functional expression of the MC2R. The melanocortin receptor (MCR) family (MC1R to MC5...

Background: GH insensitivity (GHI) presents with growth failure, IGF-1 deficiency and normal/elevated GH (basal >5 μg/l and/or peak >10 μg/l). GHI encompasses a spectrum of clinical and biochemical abnormalities. Associations between phenotypic characteristics and genetic defects remain obscure.Objective: Identify phenotypic predictors of underlying genetic defects in GHI.Methods: In total of 102 children (62M) me...

Background: Growth hormone insensitivity (GHI) is a continuum defined by normal/elevated growth hormone (GH), low IGF-I levels and growth restriction. Non-classical/mild-moderate GHI is poorly characterised and is frequently underdiagnosed. Heterozygous dominant negative (DN) gene variants located in the regions encoding the intracellular/transmembrane domains of the GH receptor cause a ‘non-classical’ GHI phenotype.Hypothesis/Objective: Detail...

Case history: Two unrelated male patients were referred for evaluation of short stature. The first patient aged 16.5 years, had a birth weight of 2.6 kg at term (BWSDS -2.4), height 153 cm (HSDS -3.2) at referral and normal BMI SDS of 0.6. He had early postnatal hypoglycemia, which was conservatively managed, but no other significant clinical history. He had relative macrocephaly and disproportionate short stature. His mother was also short with a similar phenotype (height 147...

Background: Pathogenic IGFI gene mutations causing childhood growth failure are extremely rare. Only five autosomal recessive mutations, one IGFI copy number variant and two heterozygous frameshift mutations are reported. Heterozygous missense IGFI mutations haven’t previously been described.Objectives: To identify and functionally characterise a novel missense IGFI variant in a patient with postnatal growth failu...

Background: GH Insensitivity (GHI) is usually caused by mutations in the GH receptor (GHR). Our centre previously described the first GHR pseudoexon mutation (42700896A>G, c. 618+792A>G). Inclusion of this 108bp pseudoexon is predicted to lead to in-frame insertion of 36 amino acid residues in the dimerization domain of the GHR. This results in defective trafficking rather than impaired signalling, causing partial loss-of-function and moderat...

Background: Self-limited delayed puberty (DP) often segregates in an autosomal dominant pattern, suggesting that inheritance is conferred by a small number of genes. However, the underlying genetic background is mostly unknown. By comparison, many genes have been identified where loss-of-function mutations lead to hypogonadotropic hypogonadism (HH). Despite likely overlap between the pathophysiology of delayed puberty and conditions of GnRH deficiency, few studies have examine...

Background: Growth Hormone Insensitivity is usually caused by mutations in the Growth Hormone receptor (GHR). Patients present with short stature, high GH levels, low IGF-I levels and typical Laron syndrome facial features. Our centre previously described the first GHR pseudoexon mutation (42700896A>G, c.618+792A>G). The inclusion of this pseudoexon is predicted to cause in-frame insertion of 36 amino acid residues between exons 6 and 7. This insertion in the ...