Neonatal hyperinsulinism in transient and classical forms of tyrosinemia.

Background: The spectrum of disorders associated with hyperinsulinemic hypoglycemia (HHI) has vastly increased over the past 20 years with identification of molecular, metabolic and cellular pathways involved in the regulation of insulin secretion and its actions. Hereditary tyrosinemia (HT1) is a rare metabolic disorder associated with accumulation of toxic metabolites of the tyrosine pathway due to a genetically mediated enzyme defect of fumarylacetoacetate hydrolase. Transient tyrosinemia of the newborn (TTN) is a benign condition with a maturational defect of the enzymes associated with tyrosine metabolism without any genetic abnormalities.

Undervirilized male infant with in utero exposure to maternal use of high dose antifungal therapy.

Background: Antifungals act on fungal sterols structurally similar to human cholesterol. Ketoconazole reversibly suppresses steroidogenesis by inhibiting cytochrome P450 enzymes and interferes with dihydrotestosterone (DHT) activity by binding to the androgen receptor. Hypospadias was reported in infants exposed to nystatin in utero.

Endocrine Complications of Noonan Syndrome beyond Short Stature.

Noonan syndrome (NS) is a diagnosis that is made clinically based on features including typical facies, congenital heart defects, short stature and developmental delay. Approximately 50% of the patients have identified mutations in the PTPN11 gene, and a smaller percentage of mutations have been reported in other genes such as SOS1, RAF1 and RIT1 Despite normal birth length, patients typically reach adult height below normal. Other than growth, endocrine complications of NS are not as commonly reported.

Primary Cortisol Deficiency and Growth Hormone Deficiency in a Neonate With Hypoglycemia: Coincidence or Consequence?

Cortisol and growth hormone (GH) deficiencies are causes of neonatal hypoglycemia. When they coexist, a pituitary disorder is suspected. We present an infant with hypoglycemia in whom an ACTH receptor defect was associated with transient GH deficiency.

Autoimmune hyperphosphatemic tumoral calcinosis in a patient with FGF23 autoantibodies.

Hyperphosphatemic familial tumoral calcinosis (HFTC)/hyperostosis-hyperphosphatemia syndrome (HHS) is an autosomal recessive disorder of ectopic calcification due to deficiency of or resistance to intact fibroblast growth factor 23 (iFGF23). Inactivating mutations in FGF23, N-acetylgalactosaminyltransferase 3 (GALNT3), or KLOTHO (KL) have been reported as causing HFTC/HHS. We present what we believe is the first identified case of autoimmune hyperphosphatemic tumoral calcinosis in an 8-year-old boy.

Genetic Techniques in the Evaluation of Short Stature.

Normal growth is a complex dynamic process dependent on the coordination of multiple factors including genetics, nutrition and hormones that are all working in balance. This chapter will review selected features of commonly utilized genetic techniques such as chromosomal analysis, microarray analysis, targeted gene screening and whole exome sequencing that are being used to identify genes influencing growth. As genetic technologies continue to improve and become more accessible many of these techniques will help to provide a better understanding of mechanisms underlying abnormal growth and will eventually lead to novel management approaches for abnormal growth.

Altered somatotroph feedback regulation improves metabolic efficiency and limits adipose deposition in male mice.

Several transgenic mouse models with disruption in the growth hormone (GH) axis support the role of GH in augmenting metabolic homeostasis. Specifically, interest has focused on GH's lipolytic properties and ability to affect adipose deposition. Furthermore, both GH and insulin growth factor 1 (IGF-1) may also play a direct or indirect role in adipose development.

Both estrogen receptor α and β stimulate pituitary GH gene expression.

Although sex steroids have been implicated in the control of mammalian growth, their direct effect on GH synthesis is less clear. The aim of this study was to establish whether estradiol (E2) directly affects GH synthesis in somatotrophs. Somatotroph GH3 and MtT/S cells were used as in vitro models.

Isolated prolactin deficiency associated with serum autoantibodies against prolactin-secreting cells.

Context: Isolated prolactin (PRL) deficiency is a rare entity of unknown etiology manifesting as failure of puerperal lactogenesis.

Objective: The aim of the study was to determine the cause of isolated PRL deficiency in an affected woman.

Design And Setting: We examined genetic and autoimmune causes of isolated PRL deficiency at academic medical centers.

Vertical transmission of hypopituitarism: critical importance of appropriate interpretation of thyroid function tests and levothyroxine therapy during pregnancy.

Background: Typically, newborns with congenital hypothyroidism are asymptomatic at birth, having been exposed to euthyroid mothers. However, hypopituitarism may be associated with central hypothyroidism, preserved fertility, and autosomal dominant inheritance, requiring increased attention to thyroid management during pregnancy.

Patient Findings: A woman with a history of growth hormone deficiency and central hypothyroidism gave birth to a term male neonate appropriate for gestational age.

Insulin-like growth factor 1 mediates negative feedback to somatotroph GH expression via POU1F1/CREB binding protein interactions.

Circulating insulin-like growth factor 1 (IGF-1) has been shown to act as a negative feedback regulator of growth hormone (GH) gene expression; however, the mechanism of this negative feedback is poorly understood. Activation and regulation of GH gene expression require the binding of the transcription factor POU1F1 to the GH promoter along with cyclic AMP (cAMP) response element binding protein (CREB) binding protein (CBP). We investigate the role of CBP as a target of IGF-1 somatotroph regulation using the MtT/S somatotroph cell line.

A novel OTX2 mutation in a patient with combined pituitary hormone deficiency, pituitary malformation, and an underdeveloped left optic nerve.

Orthodenticle homolog 2 (OTX2) is a homeobox family transcription factor required for brain and eye formation. Various genetic alterations in OTX2 have been described, mostly in patients with severe ocular malformations. In order to expand the knowledge of the spectrum of OTX2 mutation, we performed OTX2 mutation screening in 92 patients with combined pituitary hormone deficiency (CPHD).

Genetic overlap in Kallmann syndrome, combined pituitary hormone deficiency, and septo-optic dysplasia.

Context: Kallmann syndrome (KS), combined pituitary hormone deficiency (CPHD), and septo-optic dysplasia (SOD) all result from development defects of the anterior midline in the human forebrain.

Objective: The objective of the study was to investigate whether KS, CPHD, and SOD have shared genetic origins.

Design And Participants: A total of 103 patients with either CPHD (n = 35) or SOD (n = 68) were investigated for mutations in genes implicated in the etiology of KS (FGFR1, FGF8, PROKR2, PROK2, and KAL1).

Novel mutations associated with combined pituitary hormone deficiency.

The pituitary gland produces hormones that play important roles in both the development and the homeostasis of the body. A deficiency of two or several of these pituitary hormones, known as combined pituitary hormone deficiency, may present in infants or children due to an unknown etiology and is considered congenital or idiopathic. Advancements in our understanding of pituitary development have provided a genetic basis to explain the pathophysiological basis of pituitary hormone disease.

Targeted deletion of somatotroph insulin-like growth factor-I signaling in a cell-specific knockout mouse model.

The role of IGF-I in the negative regulation of GH expression and release is demonstrated by in vitro and in vivo models; however, the targets and mechanisms of IGF-I remain unclear. We have developed a cell-specific knockout mouse in which the IGF-I receptor was ablated from the somatotroph in order to validate and characterize IGF-I negative regulation; we termed this the somatotroph IGF-I receptor knockout (SIGFRKO) mouse. The SIGFRKO mice demonstrated increased GH gene expression and secretion as well as increased serum IGF-I.

The molecular basis of hypopituitarism.

Hypopituitarism is defined as the deficiency of one or more of the hormones secreted by the pituitary gland. Several developmental factors necessary for pituitary embryogenesis and hormone secretion have been described, and mutations of these genes in humans provide a molecular understanding of hypopituitarism. Genetic studies of affected patients and their families provide insights into possible mechanisms of abnormal pituitary development; however, mutations are rare.