Heterogeneity of the growth phenotype and birth size in acid-labile subunit (ALS) deficiency.

PURPOSE: The IGFALS gene encodes the acid-labile subunit (ALS) protein, which regulates circulating IGF-1. Human IGFALS mutations cause growth hormone insensitivity (GHI) associated with ALS, IGF-1 and IGFBP-3 deficiencies and mild to moderate postnatal growth impairment (height SDS -2 to -4). Prenatal growth impairment is not a recognised feature of this disorder, but heterozygous carriers may show an intermediate phenotype. METHODS: We report a family of five subjects, including three children born small for gestational age, who were investigated for IGFALS gene mutations. RESULTS: The proband, an 8.7 years female with pre- and postnatal growth failure (BW SDS -3.04, Ht SDS -3.86) and biochemical features of GHI, had a homozygous mutation of IGFALS, c.401T>A; p.L134Q. Her 6.1 years brother (BW SDS -2.11, Ht SDS -2.0) had the same homozygous IGFALS mutation. Both parents [adult height SDS -1.76 (father) and -1.82 (mother)] and her 2.7 years sister (BW SDS -2.60, Ht SDS -2.04) were heterozygous for the IGFALS mutation. CONCLUSION: Significant phenotypic heterogeneity was observed between family members, in particular varying degrees of prenatal growth retardation were present in the three siblings, which may have contributed to the variation in the postnatal growth phenotype.

Association analysis of ten candidate genes in a large multinational cohort of small for gestational age children and children with idiopathic short stature (NESTEGG study).

BACKGROUND: Fetal growth failure has been associated with an increased risk of hypertension, cardiovascular disease and diabetes in adulthood. Exploring the mechanisms underlying this association should improve our understanding of these common adult diseases. PATIENTS AND METHODS: We investigated 225 SNPs in 10 genes involved in growth and glucose metabolism (GH1, GHR, IGF1, IGF1R, STAT5A, STAT5B, MAPK1, MAPK3, PPARγ and INS) in 1,437 children from the multinational NESTEGG consortium: 345 patients born small for gestational age who remained short (SGA-S), 288 who showed catch-up growth (SGA-Cu), 410 idiopathic short stature (ISS) and 394 controls. We related genotype to pre- and/or postnatal growth parameters, response to growth hormone (if applicable) and blood pressure. RESULTS: We found several clinical associations for GH1, GHR, IGF1, IGF1R, PPARγ and MAPK1. One SNP remained significant after Bonferroni's correction: IGF1R SNP rs4966035's minor allele A was significantly more prevalent among SGA and associated with smaller birth length (p = 0.000378) and birth weight (weaker association), independent of gestational age. CONCLUSION: IGF1R SNP rs4966035 is significantly associated with birth length, independent of gestational age. This and other associations suggest that polymorphisms in these genes might partly explain the phenotype of short children born SGA and children with ISS.

Mathematical modelling to restore circulating IGF-1 concentrations in children with Crohn's disease-induced growth failure: a pharmacokinetic study.

OBJECTIVES: Children with Crohn's disease grow poorly, and inflammation depresses the response of insulin-like growth factor-1 (IGF-1) to growth hormone. Correcting the inflammation normalises growth velocity; however, removing inflammation cannot be achieved in all children. Our lack of understanding of IGF-1 kinetics has hampered its use, particularly as high IGF-1 concentrations over long periods may predispose to colon cancer. We hypothesised that mathematical modelling of IGF-1 would define dosing regimes that return IGF-1 concentrations into the normal range, without reaching values that risk cancer. DESIGN: Pharmacokinetic intervention study. SETTING: Tertiary paediatric gastroenterology unit. PARTICIPANTS: 8 children (M:F; 4:4) entered the study. All completed: 5 South Asian British; 2 White British; 1 African British. INCLUSION CRITERIA: Children over 10 years with active Crohn's disease (C reactive protein >10 mg/l or erythrocyte sedimentation rate >25 mm/h) and height velocity <-2 SD score. EXCLUSION CRITERIA: closed epiphyses; corticosteroids within 3 months; neoplasia or known hypersensitivity to recombinant human IGF-1 (rhIGF-1). INTERVENTIONS: Subcutaneous rhIGF-1 (120 µg/kg) per dose over two admissions: the first as a single dose and the second as twice daily doses over 5 days. PRIMARY OUTCOME: Significant increase in circulating IGF-1. SECONDARY OUTCOMES: Incidence of side effects of IGF-1. A mathematical model of circulating IGF-1 (Ac) was developed to include parameters of endogenous synthesis (Ksyn); exogenous uptake (Ka) from the subcutaneous dose (As): and IGF-1 clearance: where dAc/dt=Ksyn - Kout×Ac+Ka×As. RESULTS: Subcutaneous IGF-1 increased concentrations, which were maintained on twice daily doses. In covariate analysis, disease activity reduced Ksyn (p<0.001). Optimal dosing was derived from least squares regression fitted to a dataset of 384 Crohn's patients, with model parameters assigned by simulation. CONCLUSIONS: By using age, weight and disease activity scaling in IGF-1 dosing, over 95% of children will have normalised IGF-1 concentrations below +2.5 SDs of the normal population mean, a level not associated with cancer risk.

Use of intravenous etomidate to control acute psychosis induced by the hypercortisolaemia in severe paediatric Cushing's disease.

BACKGROUND: Psychosis secondary to paediatric Cushing's disease (CD) is extremely rare and presents a significant management challenge. METHOD: We report a 14.7-year-old CD patient with acute psychosis and self-inflicted injuries following failed transsphenoidal pituitary surgery. Her mental state rapidly deteriorated precluding medical therapy. RESULTS: Emergency intravenous low-dose etomidate infusion (3-3.5 mg/h) with dose titration according to the serum cortisol combined with a hydrocortisone infusion, in an intensive care setting, was effective in controlling the hypercortisolaemia. Her mental state improved with normalisation of her cortisol levels enabling oral administration of ketoconazole and bilateral adrenalectomy to be performed. CONCLUSION: This case illustrates the safe and effective use of a low-dose etomidate infusion in an unusual case of paediatric CD.

Comparisons in the epidemiology, diagnostic features and cure rate by transsphenoidal surgery between paediatric and adult-onset Cushing's disease.

OBJECTIVE: There are few published comparisons between paediatric and adult-onset Cushing's disease (CD). We compare the epidemiology, diagnostic features and cure rate by transsphenoidal surgery (TSS) in these groups. DESIGN: Retrospective review of patient databases in a single university hospital centre. PATIENTS: Totally, 41 paediatric (mean age 12.3 ± 3.5 years; range 5.7-17.8) and 183 adult (mean age 40 ± 13 years; range 18.0-95.0) patients with CD were investigated. RESULTS: Paediatric CD was characterised by male (63%) and adult CD by a female predominance (79%, P<0.0001). There were small but significant differences in clinical presentation. Biochemical features of CD were comparable except the serum cortisol increase during a CRH test: mean change (105%, n=39) in paediatric and (54%, n=123) in adult subjects (P<0.0001). Macroadenomas were more common in adult (15%, 28/183) than in paediatric (2%, 1/41, P=0.04) CD. Corticotroph microadenomas were more easily visualised by pituitary magnetic resonance imaging (MRI) in adult (76%, 50/66) compared with paediatric (55%, 21/38, P=0.045) CD with poorer concordance of imaging with surgical findings in children (P=0.058). The incidence of ACTH lateralisation by bilateral simultaneous inferior petrosal sinus sampling was comparable in paediatric (76%, 25/33) and adult (79%, 46/58; P=0.95) patients with good surgical concordance in both (82% paediatric and 79% adult). Cure rates by TSS were comparable, with a paediatric cure rate of 69%. CONCLUSION: Several features of paediatric CD are distinct: increased frequency of prepubertal CD in males, the different clinical presentation, the decreased presence of macroadenomas and the frequent absence of radiological evidence of an adenoma on MRI.

Pediatric endocrine screening for von Hippel-Lindau disease: benefits and the challenge of compliance.

Fifteen children and adolescents (4 male) with a median age of 5.4 yr (range 1.2 -13.6 yr) were entered into a screening protocol to identify lesions of von Hippel-Lindau (VHL) disease. Fourteen had an affected first-degree relative and one had a previous VHL lesion. Screening during the period of 2000 to 2008 followed published guidelines and consisted of measurement of urinary catecholamines, adrenal and renal imaging and ophthalmological and central nervous system examinations and imaging. Screening identified 8 VHL lesions in 6 asymptomatic patients with confirmed genetic mutations. Five patients had elevated urinary noradrenaline excretion and in each case the presence of a pheochromocytoma was identified on adrenal magnetic resonance imagin scan. In one patient a left-sided tumor was identified 1 yr after a right-sided tumor had been removed. In a sixth patient a retinal capillary hemangioma and a cerebellar hemangioblastoma were identified. Patient compliance with the screening protocol was variable reflecting its time-intensive nature. A formal screening programme for this at-risk population of pediatric patients, despite being intensive, can identify VHL lesions during a pre-morbid phase and may thus have a beneficial impact on prognosis in this serious disorder.

Pathophysiology, assessment and management of the child with growth hormone resistance.

Defects in the growth hormone (GH)-insulin-like growth factor (IGF)I axis may cause GH resistance characterized by IGFI deficiency and growth failure. The range of defects causing GH resistance is broad as are their biochemical and phenotypical characteristics. We propose that GH-IGFI axis defects form a continuum of clinical and biochemical effects ranging from GH deficiency to GH resistance. The pathophysiology of GH resistance is described followed by a scheme for investigation of the child with severe short stature and normal GH secretion. We critically discuss GH therapy for such patients and define acceptable growth responsiveness. Finally we discuss therapy with IGF-I within the limits of the USA Food and Drug Administration and European Medicines Agency labels for GH resistance.

Acid-labile subunit deficiency and growth failure: description of two novel cases.

BACKGROUND/AIMS: Mutations in the acid-labile subunit (ALS) gene (IGFALS) have been associated with circulating insulin-like growth factor I (IGF-I) deficiency and short stature. Whether severe pubertal delay is also part of the phenotype remains controversial due to the small number of cases reported. We report 2 children with a history of growth failure due to novel IGFALS mutations. METHODS: The growth hormone receptor gene (GHR) and IGFALS were analyzed by direct sequencing. Ternary complex formation was studied by size exclusion chromatography. RESULTS: Two boys of 13.3 and 10.6 years, with pubertal stages 2 and 1, had mild short stature (-3.2 and -2.8 SDS, respectively) and a biochemical profile suggestive of growth hormone resistance. No defects were identified in the GHR. Patient 1 was homozygous for the IGFALS missense mutation P73L. Patient 2 was a compound heterozygote for the missense mutation L134Q and a novel GGC to AG substitution at position 546-548 (546-548delGGCinsAG). The latter causes a frameshift and the appearance of a premature stop codon. Size exclusion chromatography showed no peaks corresponding to ternary and binary complexes in either patient. CONCLUSION: Screening of the IGFALS is important in children with short stature associated with low serum IGF-I, IGFBP-3 and ALS.

Diagnosis, management and therapeutic outcome in prepubertal Cushing's disease.

OBJECTIVES: Cushing's disease (CD) in prepubertal children is very rare and presents important diagnostic and therapeutic challenges. We report experience of the management of this subpopulation of CD patients. STUDY DESIGN/METHODS: Retrospective patient case note review. RESULTS: Between 1985 and 2008, 17 prepubertal children (13M, 4F), aged 5.7-14.1 years presented to our centre for diagnosis and management of CD. All children had subnormal linear growth and excessive weight gain at presentation. A high proportion (85% of males, 75% of females) had evidence of excessive virilisation. Striae and hypertension were seen in 41% of patients. The investigation with highest sensitivity (100%) for CD was excessive increase of serum cortisol to i.v. CRH (mean increase 113%). Pituitary imaging performed in all the patients showed poor concordance with findings at surgery (31%). In contrast bilateral simultaneous inferior petrosal sinus sampling (BSIPSS), performed in 11/16 subjects showed a high correlation with surgical findings (91%). In 16 patients, transsphenoidal selective adenomectomy (TSS) achieved a cure rate of 44%. However, in the 11 patients who had pre-operative BSIPSS, the cure rate was 64%. Of the 16 patients, 9 patients who were not cured by TSS received external pituitary radiotherapy. CONCLUSIONS: Prepubertal CD had distinctive features with increased frequency in males, abnormal auxology and excessive virilisation. The cortisol response to i.v. CRH administration was particularly exuberant and contributed to diagnosis. BSIPSS was much more helpful than pituitary imaging in localisation of the microadenoma and was associated with improved cure rate by TSS.

Identification and characterisation of a novel GHR defect disrupting the polypyrimidine tract and resulting in GH insensitivity.

OBJECTIVE: GH insensitivity (GHI) is caused in the majority of cases by impaired function of the GH receptor (GHR). All but one known GHR mutation are in the coding sequence or the exon/intron boundaries. We identified and characterised the first intronic defect occurring in the polypyrimidine tract of the GHR in a patient with severe GHI. DESIGN: We investigated the effect of the novel defect on mRNA splicing using an in vitro splicing assay and a cell transfection system. METHODS: GHR was analysed by direct sequencing. To assess the effect of the novel defect, two heterologous minigenes (wild-type and mutant L1-GHR8-L2) were generated by inserting GHR exon 8 and its flanking wild-type or mutant intronic sequences into a well-characterised splicing reporter (Adml-par L1-L2). (32)P-labelled pre-mRNA was generated from the two constructs and incubated in HeLa nuclear extracts or HEK293 cells. RESULTS: Sequencing of the GHR revealed a novel homozygous defect in the polypyrimidine tract of intron 7 (IVS7-6T>A). This base change does not involve the highly conserved splice site sequences, and is not predicted in silico to affect GHR mRNA splicing. Nevertheless, skipping of exon 8 from the mutant L1-GHR8-L2 mRNA was clearly demonstrated in the in vitro splicing assay and in transfected HEK293 cells. CONCLUSION: Disruption of the GHR polypyrimidine tract causes aberrant mRNA splicing leading to a mutant GHR protein. This is predicted to lack its transmembrane and intracellular domains and, thus, be incapable of transducing a GH signal.

Consensus statement on the diagnosis and treatment of children with idiopathic short stature: a summary of the Growth Hormone Research Society, the Lawson Wilkins Pediatric Endocrine Society, and the European Society for Paediatric Endocrinology Workshop.

OBJECTIVE: Our objective was to summarize important advances in the management of children with idiopathic short stature (ISS). PARTICIPANTS: Participants were 32 invited leaders in the field. EVIDENCE: Evidence was obtained by extensive literature review and from clinical experience. CONSENSUS: Participants reviewed discussion summaries, voted, and reached a majority decision on each document section. CONCLUSIONS: ISS is defined auxologically by a height below -2 sd score (SDS) without findings of disease as evident by a complete evaluation by a pediatric endocrinologist including stimulated GH levels. Magnetic resonance imaging is not necessary in patients with ISS. ISS may be a risk factor for psychosocial problems, but true psychopathology is rare. In the United States and seven other countries, the regulatory authorities approved GH treatment (at doses up to 53 microg/kg.d) for children shorter than -2.25 SDS, whereas in other countries, lower cutoffs are proposed. Aromatase inhibition increases predicted adult height in males with ISS, but adult-height data are not available. Psychological counseling is worthwhile to consider instead of or as an adjunct to hormone treatment. The predicted height may be inaccurate and is not an absolute criterion for GH treatment decisions. The shorter the child, the more consideration should be given to GH. Successful first-year response to GH treatment includes an increase in height SDS of more than 0.3-0.5. The mean increase in adult height in children with ISS attributable to GH therapy (average duration of 4-7 yr) is 3.5-7.5 cm. Responses are highly variable. IGF-I levels may be helpful in assessing compliance and GH sensitivity; levels that are consistently elevated (>2.5 SDS) should prompt consideration of GH dose reduction. GH therapy for children with ISS has a similar safety profile to other GH indications.

Idiopathic short stature: definition, epidemiology, and diagnostic evaluation.

Idiopathic short stature is a condition in which the height of the individual is more than 2 SD below the corresponding mean height for a given age, sex and population, in whom no identifiable disorder is present. It can be subcategorized into familial and non-familial ISS, and according to pubertal delay. It should be differentiated from dysmorphic syndromes, skeletal dysplasias, short stature secondary to a small birth size (small for gestational age, SGA), and systemic and endocrine diseases. ISS is the diagnostic group that remains after excluding known conditions in short children.

Idiopathic short stature: management and growth hormone treatment.

In the management of ISS auxological, biochemical, psychosocial and ethical elements have to be considered. In boys with constitutional delay of growth and puberty androgens are effective in increasing height and sexual characteristics, but adult height is unchanged. GH therapy is efficacious in increasing height velocity and adult height, but the inter-individual variation is considerable. The effect on psychosocial status is uncertain. Factors affecting final height gain include GH dose, height deficit in comparison to midparental height, age and first year height velocity. In case of a low predicted adult height at the onset of puberty, addition of a GnRH analogue can be considered. Although GH therapy appears safe, long-term monitoring is recommended.

Clinical and endocrine features and long-term outcome of Graves' disease in early childhood.

Hyperthyroidism is rare in early childhood and most commonly caused by Graves' disease. We report 14 children (4 boys, 10 girls) aged 3.4-7.5 yr. At diagnosis, all patients had weight loss, hyperkinetic activity, tachycardia, difficulty sleeping, and poor concentration and 11 presented with proptosis. Four patients developed long-term neuropsychological problems. There was a family history in 7 cases. All patients had goiters, clinically assessed to be large and diffuse in 21%, medium-sized in 43%, and small in 36%. At diagnosis, height was increased with median (range) height; 1.25 standard deviation score (SDS) (-0.2-5.24) and body mass index (BMI) was decreased; -0.48 SDS (-1.65-1.26). Height and BMI SDS values were statistically different (p<0.032) Bone age was advanced in 4 of 5 children, who had assessments. Total or free T4 levels were elevated and TSH was undetectable. Ninety percent of patients (12/14) had positive thyroid peroxidase autoantibodies, mean level 680 IU/ml (range 50-1347). Initial treatment was with antithyroid medication using carbimazole; median dose 0.75 mg/kg/day (no.=13) or propylthiouracyl 15 mg/kg/day (no.=1). T4 was added in 6 patients. Normalisation of serum T4 occurred at 4 months (1- 9) and TSH at 7 months (3-24) after start of therapy. Treatment was discontinued after a minimum of 2 yr in 11 patients, relapse occurring in 9. Median duration of total therapy was 58 months (18-132). During adolescence, 4 patients had curative therapy by surgery (no.=2) or radioiodine (no.=2). In conclusion, disturbance of growth, behavioral difficulties and infrequent spontaneous remission are key features of Graves' disease in early childhood.

Excellent growth response to growth hormone therapy in a child with PTPN11-negative Noonan syndrome and features of growth hormone resistance.

We report a child with Noonan syndrome, referred with severe short stature (height--5.4 SD) and biochemical features of GH resistance. The Noonan syndrome phenotype was confirmed by a clinical geneticist, however analysis of the protein tyrosine phosphatase nonreceptor type 11 (PTPN11) gene showed no mutation. Baseline serum IGF-I, IGFbinding protein 3 (IGFBP-3) and acid-labile subunit (ALS) were low, and in an IGF-I generation test, IGF-I did not increase into the normal range and IGFBP-3 and ALS did not change. These results are consistent with GH resistance. Treatment with human GH (hGH) was given in a dose of 0.05 mg/kg/day and height velocity increased from 5.6 to 10.7 cm/yr during the first year, and 8.9 cm/yr during the second year of therapy. Height standard deviation score has increased by 1.85 after 2 and a half yr of therapy. Serum IGF-I, IGFBP-3 and ALS values increased well into the normal range. This case shows that the potential value of GH therapy must be evaluated in each patient individually and that an excellent response may occur in a child with a PTPN11-negative genotype.

GH responsiveness in a large multinational cohort of SGA children with short stature (NESTEGG) is related to the exon 3 GHR polymorphism.

OBJECTIVE: The polymorphic deletion of exon 3 of the GH receptor (d3-GHR) has recently been linked to the magnitude of growth response to recombinant human GH (rhGH) therapy in short children with or without GH deficiency. We investigated this association in a large multinational cohort from the Network of European Studies of Genes in Growth (NESTEGG), comprising short children born small for gestational age (SGA). DESIGN: The study included short prepubertal SGA children treated with rhGH for 1 or 2 years. POPULATION: Two hundred and forty white Caucasian SGA children (138 male, 102 female) aged 6.6 +/- 2.3 years with a height at -3.0 +/- 0.7 SDS at start of rhGH treatment; 193 ethnically matched controls. METHODS: The GHR polymorphism (fl/fl, fl/d3 or d3/d3) was genotyped by polymerase chain reaction (PCR) multiplex assay. Growth velocity (G/V) in cm/year and changes in GV during the first and second year of rhGH treatment were evaluated. RESULTS: The change in GV was significantly greater in SGA children carrying one or two copies of the d3-GHR allele (P = 0.038 for the first year and P = 0.041 for the second year of GH treatment), but the change in height was not significantly different. Birthweight was significantly lower in SGA children with the d3/d3 genotype than in SGA children with the fl/fl genotype (P = 0.034) and in those with the fl/d3 genotype (P = 0.016). CONCLUSION: Our data, based on a large cohort, showed that the exon 3 GHR polymorphism is associated with responsiveness to rhGH treatment in SGA children with short stature.

Abnormal puberty in paediatric Cushing's disease: relationship with adrenal androgen, sex hormone binding globulin and gonadotrophin concentrations.

OBJECTIVE: Paediatric Cushing's disease is frequently associated with abnormal puberty. We addressed the hypothesis that prepubertal patients show excessive virilization and pubertal patients show suppression of LH and FSH secretion. DESIGN AND MEASUREMENTS: Serum androstenedione (A4), dehydroepiandrosterone sulphate (DHEAS), testosterone (T), and sex hormone binding globulin (SHBG) were determined at diagnosis and converted to standard deviation scores. LH, FSH concentrations were also determined. Severity of CD was assessed from the sleeping midnight cortisol concentration. Puberty was staged and excessive virilization defined as advance in pubic hair stage for breast stage or testicular volume (TV). PATIENTS: Twenty-seven CD patients (17 male, 10 female), median age 13.4 years (range 5.9-17.8) were studied. RESULTS: In the CD group as a whole, A4, DHEAS, T standard deviation scores (SDS) values were normal. SHBG SDS values (n = 19) were low (median -1.93, -4.32-0.86) correlating with BMI (r = -0.49). A4, DHEAS, T, SHBG, LH and FSH did not correlate with midnight cortisol, but A4 and T SDS correlated with ACTH at 09.00 h (both r = 0.51). Thirteen patients (11 male, 2 female) had excessive virilization with increased A4 (P = 0.033), DHEAS (P = 0.008), testosterone (P = 0.033) and decreased SHBG (P = 0.004) compared with subjects without excessive virilization. Pubertal boys (TV > or = 4 ml) (n = 7) and girls (breasts > or = stage 2) (n = 8) had low median LH and FSH. Boys had an LH concentration of 1.2 mU/l (0.3-3.5), FSH, 0.9 mU/l (0.2-6.4) and median T SDS, -1.95 (-3.8-4.65), while girls had an LH concentration of 1 mU/l (0.3-7.4). CONCLUSIONS: Many patients had abnormal puberty and excessive virilization associated with increased adrenal androgens and decreased SHBG. Pubertal patients had low LH and FSH suggesting impaired pituitary-gonadal axis function.

Defects in growth hormone receptor signaling.

Severe growth failure and insulin-like growth factor (IGF) deficiency were first reported 40 years ago in patients who ultimately proved to have mutations in the gene encoding the growth hormone receptor (GHR). So far, over 250 similar patients, encompassing more than 60 different mutations of GHR, have been reported. The GHR is a member of the cytokine receptor superfamily and has been shown to signal, at least in part, through the Janus-family tyrosine kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Six patients, from five distinct families, have been reported to have phenotypes similar to that of patients with GHR defects but with wild-type receptors and homozygosity for five different mutations of the STAT5b gene. These patients define a new cause of GH insensitivity and primary IGF deficiency and confirm the crucial role of STAT5b in GH-mediated IGF-I gene transcription.