Mild deficits in attentional control in patients with the IGSF1 deficiency syndrome

OBJECTIVE

Male patients with the X-linked IGSF1 deficiency syndrome are characterized by central hypothyroidism, delayed pubertal testosterone rise, adult macroorchidism, variable prolactin deficiency and occasionally transient partial growth hormone deficiency. Thyroid hormone plays a vital role in brain development and functioning, and while most patients receive adequate replacement therapy starting shortly after birth, it is unknown whether this syndrome is accompanied by long-term impaired cognitive functioning. We therefore assessed cognitive functioning in male patients with IGSF1 deficiency.

METHODS

Fifteen adult male patients with IGSF1 deficiency participated in neuropsychological assessment of executive functioning and memory, and completed validated questionnaires on health-related quality of life (HRQoL), mood and fatigue. Results were compared to data from previous studies by our department: 54 healthy controls (76 for the attention task) for the test battery and 191 healthy controls for the questionnaires.

RESULTS

All patients had central hypothyroidism, and twelve were treated with levothyroxine. Patients performed worse than controls in tasks that required attentional control (Trail Making Test, Letter-Digit Substitution Test, and Sustained Attention to Response Task) (all P < 0·001). Memory was unaffected. In addition, patients reported more mental fatigue and reduction of activity (Multidimensional Fatigue Inventory) (both P < 0·01), while HRQoL and mood reports were not different from controls. Age at the start of replacement therapy and current thyroxine levels were not related to outcome.

CONCLUSIONS

Adult male patients with IGSF1 deficiency exhibit mild deficits in attentional control on formal testing. This finding was not related to the age at start of replacement therapy, or current levothyroxine treatment.

IGSF1 Deficiency: Lessons From an Extensive Case Series and Recommendations for Clinical Management

CONTEXT

Mutations in the immunoglobulin superfamily, member 1 (IGSF1) gene cause the X-linked IGSF1 deficiency syndrome consisting of central hypothyroidism, delayed pubertal testosterone rise, adult macroorchidism, variable prolactin deficiency, and occasionally transient partial GH deficiency. Since our first reports, we discovered 20 new families with 18 new pathogenic IGSF1 mutations.

OBJECTIVE

We aimed to share data on the largest cohort of patients with IGSF1 deficiency to date and formulate recommendations for clinical management.

METHODS

We collected clinical and biochemical characteristics of 69 male patients (35 children, 34 adults) and 56 female IGSF1 mutation carriers (three children, 53 adults) from 30 unrelated families according to a standardized clinical protocol. At evaluation, boys were treated with levothyroxine in 89%, adult males in 44%, and females in 5% of cases.

RESULTS

Additional symptoms in male patients included small thyroid gland volume (74%), high birth weight (25%), and large head circumference (20%). In general, the timing of pubertal testicular growth was normal or even premature, in contrast to a late rise in T levels. Late adrenarche was observed in patients with prolactin deficiency, and adult dehydroepiandrosterone concentrations were decreased in 40%. Hypocortisolism was observed in 6 of 28 evaluated newborns, although cortisol concentrations were normal later. Waist circumference of male patients was increased in 60%, but blood lipids were normal. Female carriers showed low free T4 (FT4) and low-normal FT4 in 18% and 60%, respectively, delayed age at menarche in 31%, mild prolactin deficiency in 22%, increased waist circumference in 57%, and a negative correlation between FT4 concentrations and metabolic parameters.

CONCLUSION

IGSF1 deficiency represents the most common genetic cause of central hypothyroidism and is associated with multiple other characteristics. Based on these results, we provide recommendations for mutational analysis, endocrine work-up, and long-term care.

The growth response to GH treatment is greater in patients with SHOX enhancer deletions compared to SHOX defects

OBJECTIVE

Short stature caused by point mutations or deletions of the short stature homeobox (SHOX) gene (SHOX haploinsufficiency (SHI)) is a registered indication for GH treatment. Patients with a SHOX enhancer deletion (SED) have a similar phenotype, but their response to GH is unknown. It is uncertain if duplications of SHOX or its enhancer (SDUP) cause short stature. This study aimed to describe the clinical characteristics and growth response to GH treatment in patients with aberrations of SHOX and its enhancers.

DESIGN

In this retrospective multi-center study (2002-March 2014) clinical information was available from 130 patients (72 SHI, 44 SED, and 14 SDUP) of whom 52 patients were treated with GH. We evaluated height, sitting height (SH), arm span, dysmorphic features and indicators of the growth response to GH (delta height SDS, height velocity, and index of responsiveness).

RESULTS

Patients with SEDs showed similar HtSDS to patients with SHI (-2.3 and -2.6, respectively, P=0.2), but they were less disproportionate (SH/height ratio SDS 2.0 vs 3.1 (P<0.01) and extremities/trunk ratio 2.57 vs 2.43 (P=0.03)). The 1st year growth response to GH treatment was significantly greater in prepubertal patients with SEDs than SHI. None of the patients with an SDUP was disproportionate and SDUP cosegregated poorly with short stature; their growth response to GH treatment (n=3) was similar to the other groups.

CONCLUSIONS

Patients with SEDs are equally short, but less disproportionate than patients with SHI, and show a greater response to GH.

Long-term effects of oxandrolone treatment in childhood on neurocognition, quality of life and social-emotional functioning in young adults with Turner syndrome

Turner syndrome (TS) is the result of (partial) absence of one X-chromosome. Besides short stature, gonadal dysgenesis and other physical aspects, TS women have typical psychological features. Since psychological effects of androgen exposure in childhood probably are long-lasting, we explored long-term psychological functioning after oxandrolone (Ox) therapy during childhood in adults with TS in terms of neurocognition, quality of life and social-emotional functioning. During the initial study, girls were treated with growth hormone (GH) combined with placebo (Pl), Ox 0.03 mg/kg/day, or Ox 0.06 mg/kg/day from the age of eight, and estrogen from the age of twelve. Sixty-eight women participated in the current double-blinded follow-up study (mean age 24.0 years, mean time since stopping GH/Ox 8.7 years). We found no effects on neurocognition. Concerning quality of life women treated with Ox had higher anxiety levels (STAI 37.4 ± 8.4 vs 31.8 ± 5.0, p=0.002) and higher scores on the depression subscale of the SCL-90-R (25.7 ± 10.7 vs 20.5 ± 4.7, p=0.01). Regarding social-emotional functioning, emotion perception for fearful faces was lower in the Ox-treated patients, without effect on interpersonal behavior. Our exploratory study is the first to suggest that androgen treatment in adolescence possibly has long-term effects on adult quality of life and social-emotional functioning. However, differences are small and clinical implications of our results seem limited. Therefore we would not recommend against the use of Ox in light of psychological consequences.

Safety and efficacy of oxandrolone in growth hormone-treated girls with Turner syndrome: evidence from recent studies and recommendations for use

There has been no consensus regarding the efficacy and safety of oxandrolone (Ox) in addition to growth hormone (GH) in girls with Turner syndrome (TS), the optimal age of starting this treatment, or the optimal dose. This collaborative venture between Dutch, UK and US centers is intended to give a summary of the data from three recently published randomized, placebo-controlled, double-blind studies on the effects of Ox. The published papers from these studies were reviewed within the group of authors to reach consensus about the recommendations. The addition of Ox to GH treatment leads to an increase in adult height, on average 2.3–4.6 cm. If Ox dosages<0.06 mg/kg/day are used, side effects are modest. The most relevant safety concerns are virilization(including clitoromegaly and voice deepening) and a transient delay of breast development. We advise monitoring signs of virilization breast development and possibly blood lipids during Ox treatment, in addition to regular follow-up assessments for TS. In girls with TS who are severely short for age, in whom very short adult stature is anticipated,or in whom the growth rate is modest despite good compliance with GH, adjunctive treatment with Ox at a dosage of 0.03–0.05 mg/kg/day starting from the age of 8–10 years onward scan be considered.

Splice site mutations in GH1 detected in previously (Genetically) undiagnosed families with congenital isolated growth hormone deficiency type II

BACKGROUND

Congenital isolated growth hormone deficiency (IGHD) is a rare endocrine disorder that presents with severe proportionate growth failure. Dominant (type II) IGHD is usually caused by heterozygous mutations of GH1. The presentation of newly affected family members in 3 families with dominant IGHD in whom previous genetic testing had not demonstrated a GH1 mutation or had not been performed, prompted us to identify the underlying genetic cause.

METHODS

GH1 was sequenced in 3 Caucasian families with a clinical autosomal dominant IGHD.

RESULTS

All affected family members had severe growth hormone (GH) deficiency that became apparent in the first 2 years of life. GH treatment led to a marked increase in height SDS. So far, no other pituitary dysfunctions have become apparent. In the first family a novel splice site mutation in GH1 was identified (c.172-1G>C, IVS2-1G>C). In two other families a previously reported splice site mutation (c.291+1G>A, IVS3+1G>A) was found.

CONCLUSION

These data show that several years after negative genetic testing it was now possible to make a genetic diagnosis in these families with a well-defined, clearly heritable, autosomal dominant IGHD. This underscores the importance of clinical and genetic follow-up in a multidisciplinary setting. It also shows that even without a positive family history, genetic testing should be considered if the phenotype is strongly suggestive for a genetic syndrome. Identification of pathogenic mutations, like these GH1 mutations, has important clinical implications for the surveillance and genetic counseling of patients and expands our knowledge on the genotype-phenotype correlation.

Genetic analysis of GHR should contain sequencing of all coding exons and specific intron sequences, and screening for exon deletions

BACKGROUND

The work-up of patients with clinical and/or biochemical features of growth hormone insensitivity (GHI) usually contains genetic analysis of the growth hormone receptor (GHR) gene, and if negative, of STAT5B, IGFALS and IGF1. In a previous report we described 2 siblings presenting with short stature, low IGF-1 levels, elevated GH secretion and no increase of IGF-1 after 1 week of GH administration. Repeated analysis of the GHR showed no abnormalities; however, further testing revealed a heterozygous STAT5B defect in both siblings.

SUBJECTS AND METHODS

Two boys of Surinam-Hindustan origin showed growth failure up to the age of 6-7 years, followed by partial catch-up growth associated with increasing body mass index. Reanalysis of GHR including published intronic sequences was performed on the patients' DNA collected 7 years earlier.

RESULTS

The heterozygous STAT5B variant proved to be functionally benign. A homozygous intronic mutation of the GHR, c.618+792A>G (IVS6+792A>G), was subsequently found, resulting in the activation of pseudoexon 6ψ, and explaining the GHI phenotype of the patients.

CONCLUSION

An intronic GHR mutation should be considered in all patients with signs of GHI and no coding exon mutations, even if the phenotype is mild and even if other genetic variants have been found.

Pharmacokinetics and pharmacodynamics of orally administered clonidine: a model-based approach

BACKGROUND/AIMS

The oral clonidine test is a diagnostic procedure performed in children with suspected growth hormone (GH) deficiency. It is associated with untoward effects, including bradycardia, hypotension and sedation. Serum clonidine levels have not previously been assessed during this test.

METHODS

In 40 children referred for an oral clonidine test, blood samples were drawn for clonidine and GH. Vital statistics and sedation scores were recorded until 210 min post-dose. We explored the relationship between clonidine concentrations and effects such as GH peak and blood pressure.

RESULTS

Of 40 participants, 5 children were GH deficient. Peak clonidine concentrations of 0.846 ± 0.288 ng/ml were reached after 1 h. Serum levels declined slowly, with concentrations of 0.701 ± 0.189 ng/ml 210 min post-dose. A large interindividual variation of serum levels was observed. During the procedure, systolic blood pressure dropped by 12.8%, diastolic blood pressure by 19.7% and heart rate by 8.4%. Moderate sedation levels were observed. Concentration-effect modeling showed that the amount of GH available for secretion as determined by previous bursts was an important factor influencing GH response.

CONCLUSION

Clonidine concentrations during the test were higher than necessary according to model-based predictions. A lower clonidine dose may be sufficient and may produce fewer side effects.

Personalized approach to growth hormone treatment: clinical use of growth prediction models

The goal of growth hormone (GH) treatment in a short child is to attain a fast catch-up growth toward the target height (TH) standard deviation score (SDS), followed by a maintenance phase, a proper pubertal height gain, and an adult height close to TH. The short-term response variable of GH treatment, first-year height velocity (HV) (cm/year or change in height SDS), can either be compared with GH response charts for diagnosis, age and gender, or with predicted HV based on prediction models. Three types of prediction models have been described: the Kabi International Growth Hormone Study models, the Gothenburg models and the Cologne model. With these models, 50-80% of the variance could be explained. When used prospectively, individualized dosing reduces the variation in growth response in comparison with a fixed dose per body weight. Insulin-like growth factor-I-based dose titration also led to a decrease in the variation. It is uncertain whether adding biochemical, genetic or proteomic markers may improve the accuracy of the prediction. Prediction models may lead to a more evidence-based approach to determine the GH dose regimen and may reduce the drug costs for GH treatment. There is a need for user-friendly software programs to make prediction models easily available in the clinic.

The IGSF1 deficiency syndrome: characteristics of male and female patients

CONTEXT

Ig superfamily member 1 (IGSF1) deficiency was recently discovered as a novel X-linked cause of central hypothyroidism (CeH) and macro-orchidism. However, clinical and biochemical data regarding growth, puberty, and metabolic outcome, as well as features of female carriers, are scarce.

OBJECTIVE

Our objective was to investigate clinical and biochemical characteristics associated with IGSF1 deficiency in both sexes.

METHODS

All patients (n = 42, 24 males) from 10 families examined in the university clinics of Leiden, Amsterdam, Cambridge, and Milan were included in this case series. Detailed clinical data were collected with an identical protocol, and biochemical measurements were performed in a central laboratory.

RESULTS

Male patients (age 0-87 years, 17 index cases and 7 from family studies) showed CeH (100%), hypoprolactinemia (n = 16, 67%), and transient partial GH deficiency (n = 3, 13%). Pubertal testosterone production was delayed, as were the growth spurt and pubic hair development. However, testicular growth started at a normal age and attained macro-orchid size in all evaluable adults. Body mass index, percent fat, and waist circumference tended to be elevated. The metabolic syndrome was present in 4 of 5 patients over 55 years of age. Heterozygous female carriers (age 32-80 years) showed CeH in 6 of 18 cases (33%), hypoprolactinemia in 2 (11%), and GH deficiency in none. As in men, body mass index, percent fat, and waist circumference were relatively high, and the metabolic syndrome was present in 3 cases.

CONCLUSION

In male patients, the X-linked IGSF1 deficiency syndrome is characterized by CeH, hypoprolactinemia, delayed puberty, macro-orchidism, and increased body weight. A subset of female carriers also exhibits CeH.

Molecular IGF-1 and IGF-1 receptor defects: from genetics to clinical management

Molecular defects of the insulin-like growth factor 1 gene (IGF1) are rare in the human. Only three homozygous and two families with heterozygous mutations of the IGF1 gene have been described, resulting in a variable degree of intrauterine and postnatal growth retardation, microcephaly, developmental delay and deafness. Detailed genetic analysis and functional experiments have shown that IGF-1 plays a key role in pre- and postnatal growth and development in human. Eleven patients with heterozygous and 2 patients with compound heterozygous mutations in the type 1 IGF1 receptor gene (IGF1R) have been reported. Intrauterine and postnatal growth retardation, microcephaly and IGF-1 levels above the mean of age references are consistent findings in these patients, although IGF-1 levels can be low initially because of feeding problems. The first reported patients showed the most severe phenotype, but with the identification of additional patients the phenotype appears to be more variable. The functional effect of the defects has been studied by in vitro experiments. From these studies, receptor haploinsufficiency, decreased IGF1R biosynthesis, interference with ligand binding and transmembrane signaling, and disruption of the intrinsic tyrosine kinase activity have been suggested as possible mechanisms with a variable pathogenetic spectrum. Data on GH treatment in these children are limited, showing a poor to modest growth response.

Genetic analysis of short children with apparent growth hormone insensitivity

BACKGROUND/AIMS

In short children, a low IGF-I and normal GH secretion may be associated with various monogenic causes, but their prevalence is unknown. We aimed at testing GH1, GHR, STAT5B, IGF1, and IGFALS in children with GH insensitivity.

SUBJECTS AND METHODS

Patients were divided into three groups: group 1 (height SDS <-2.5, IGF-I <-2 SDS, n = 9), group 2 (height SDS -2.5 to -1.9, IGF-I <-2 SDS, n = 6) and group 3 (height SDS <-1.9, IGF-I -2 to 0 SDS, n = 21). An IGF-I generation test was performed in 11 patients. Genomic DNA was used for direct sequencing, multiplex ligation-dependent probe amplification and whole-genome SNP array analysis.

RESULTS

Three patients in group 1 had two novel heterozygous STAT5B mutations, in two combined with novel IGFALS variants. In groups 2 and 3 the association between genetic variants and short stature was uncertain. The IGF-I generation test was not predictive for the growth response to GH treatment.

CONCLUSION

In severely short children with IGF-I deficiency, genetic assessment is advised. Heterozygous STAT5B mutations, with or without heterozygous IGFALS defects, may be associated with GH insensitivity. In children with less severe short stature or IGF-I deficiency, functional variants are rare.

A mosaic de novo duplication of 17q21-25 is associated with GH insensitivity, disturbed in vitro CD28-mediated signaling, and decreased STAT5B, PI3K, and NF-κB activation

OBJECTIVE

The established causes of GH insensitivity include defects of the GH receptor and STAT5B. The latter condition is also characterized by severe immunodeficiency. A recent case with short stature, GH resistance, and immunodeficiency due to an IκB mutation suggests that the NF-κB pathway may interact with STAT5B signaling.

DESIGN

Here, we present a case of a short child with several congenital anomalies as well as GH insensitivity and mild immunodeficiency associated with a mosaic de novo duplication of chromosome 17q21-25, suggesting that overexpression of one of the duplicated genes may be implicated in GH resistance.

METHODS AND RESULTS

In vitro studies on blood lymphocytes showed disturbed signaling of the CD28 pathway, involving NF-κB and related proteins. Functional studies on cultured skin fibroblasts revealed that NF-κB activation, PI3K activity, and STAT5 phosphorylation in response to GH were suppressed, while the sensitivity to GH in terms of MAPK phosphorylation was increased. An in silico analysis of the duplicated genes showed that MAP3K3 and PRKCA are associated with the NF-κB pathway. Baseline MAP3K3 expression in T-cell blasts (TCBs) was normal, but PRKCA expression in TCBs and fibroblasts was significantly higher than that in control cells.

CONCLUSIONS

We conclude that the 17q21-25 duplication is associated with GH insensitivity and disturbed STAT5B, PI3K, and NF-κB signaling, possibly due to PRKCA mRNA overexpression.

Inhibition of Gsk3β in cartilage induces osteoarthritic features through activation of the canonical Wnt signaling pathway

OBJECTIVE

In the past years, the canonical Wnt/β-catenin signaling pathway has emerged as a critical regulator of cartilage development and homeostasis. In this pathway, glycogen synthase kinase-3β (GSK3β) down-regulates transduction of the canonical Wnt signal by promoting degradation of β-catenin. In this study we wanted to further investigate the role of Gsk3β in cartilage maintenance.

DESIGN

Therefore, we have treated chondrocytes ex vivo and in vivo with GIN, a selective GSK3β inhibitor.

RESULTS

In E17.5 fetal mouse metatarsals, GIN treatment resulted in loss of expression of cartilage markers and decreased chondrocyte proliferation from day 1 onward. Late (3 days) effects of GIN included cartilage matrix degradation and increased apoptosis. Prolonged (7 days) GIN treatment resulted in resorption of the metatarsal. These changes were confirmed by microarray analysis showing a decrease in expression of typical chondrocyte markers and induction of expression of proteinases involved in cartilage matrix degradation. An intra-articular injection of GIN in rat knee joints induced nuclear accumulation of β-catenin in chondrocytes 72 h later. Three intra-articular GIN injections with a 2 days interval were associated with surface fibrillation, a decrease in glycosaminoglycan expression and chondrocyte hypocellularity 6 weeks later.

CONCLUSIONS

These results suggest that, by down-regulating β-catenin, Gsk3β preserves the chondrocytic phenotype, and is involved in maintenance of the cartilage extracellular matrix. Short term β-catenin up-regulation in cartilage secondary to Gsk3β inhibition may be sufficient to induce osteoarthritis-like features in vivo.

Long-term effect of lifestyle intervention on adiposity, metabolic parameters, inflammation and physical fitness in obese children: a randomized controlled trial

Background:

Behavioral lifestyle intervention, combined with parental involvement, is preferred over standard care or self-help in childhood obesity. The short-term results of such interventions are promising, but long-term follow-up results are equivocal.

Objective:

The objective of the present study was the short (3 months) and long-term (1 and 2 years follow-up) effect evaluation of a family-based multidisciplinary cognitive behavioral lifestyle intervention on markers of adiposity, metabolism, inflammation and physical fitness compared with standard care in children with obesity. Also the association between these outcome variables was determined.

Methods:

In this prospective longitudinal clinical trial, obese children were randomly assigned to a 3-month family-based cognitive behavioral multidisciplinary lifestyle treatment (n=40; body mass index-standard deviation score (BMI-SDS) 4.2±0.7; age; 13.3±2.0 years) or to a control group receiving an initial advice on physical activity and nutrition (n=39; BMI-SDS 4.3±0.6; age 13.1±1.9 years). Anthropometric data, physical fitness, metabolic parameters and inflammatory state were evaluated at baseline, after intervention (at 3 months) and at 1-year follow-up. At 2-year follow-up, anthropometric data and physical fitness were measured in the intervention group.

Results:

An intervention effect after 1 year was found for adiposity (P=0.02 for BMI-SDS, P=0.03 for waist circumference (WC)-SDS), physical fitness (absolute measured peak value of oxygen uptake (ml min⁻¹), standardized for age and gender (VO_2peak-SDS), P<0.01) and insulin resistance (HOMA-SDS, P=0.04). No significant intervention effect was found for serum lipid profile, high-sensitive C-reactive protein or for adiponectin. At 2-year follow-up, BMI-SDS in the intervention group (n=31) was 3.8±1.2 SDS, significantly less than at baseline (P=0.02).

Conclusion:

A positive 1-year follow-up treatment effect was found for adiposity, physical fitness and glucose homeostasis, but not for inflammatory markers. There was a significant long-term treatment effect on adiposity, although almost all children remained obese.

Diagnosis and management of disorders of IGF-I synthesis and action

After a proper medical history, growth analysis and physical examination of a short child, followed by radiological and laboratory screening, the clinician may decide to perform genetic testing. We recently proposed several clinical algorithms that can be used to establish the diagnosis. GH insensitivity (primary IGF-I deficiency) can be caused by genetic defects in GHR, STAT5B, IGF1, IGFALS, which all have their specific clinical and biochemical characteristics. IGF-I resistance is seen in heterozygous defects of IGF1R. If besides short stature additional abnormalities are present, these should be matched with known dysmorphic syndromes. If no obvious candidate gene can be determined, a whole genome approach can be taken to check for deletions, duplications and/or uniparental disomies (SNP-array) or whole exome sequencing. Children with GHR defects, and presumably STAT5B and homozygous IGF1 defects, can be treated with rhlGF-I. Children with IGF1R defects and mild or heterozygous IGF1 defects respond to GH treatment.

Case report: low circulating IGF-I levels due to Acid-Labile Subunit deficiency in adulthood are not associated with early development of atherosclerosis and impaired heart function

OBJECTIVE

Decreased insulin-like growth factor-I (IGF-I) levels in adults have been associated with an increased risk of ischemic heart disease and heart failure. It is currently unknown whether patients with low circulating IGF-I levels due to a homozygous acid-labile subunit (IGFALS) gene mutation also have increased risk of cardiovascular disease. Therefore, we evaluated atherosclerotic burden in a 27 year old male patient who was diagnosed with a homozygous IGFALS mutation and consequently had extremely low circulating IGF-I levels.

METHODS

Ten year's cardiovascular risk was calculated using the Framingham risk score. Presence of (subclinical) atherosclerosis was assessed using a 64-slice CT scan of the coronary arteries. Cardiac performance was measured by conventional echocardiographic measurements, three dimensional (3D)-echocardiography, and tissue deformation imaging.

RESULTS

Despite his extremely low circulating IGF-I levels due to Acid-Labile Subunit (ALS) deficiency, our patient had a low Framingham risk score and no signs of coronary atherosclerosis. Adjusted for physical height, cardiac performance was not impaired compared with healthy subjects.

CONCLUSION

The present case report does not lend support to routine cardiovascular screening in patients with extremely low circulating IGF-I levels due to a homozygous IGFALS mutation, when cardiovascular risk is low.

Should blood gas analysis be part of the diagnostic workup of short children? Auxological data and blood gas analysis in children with renal tubular acidosis

BACKGROUND

Renal tubular acidosis (RTA) is a rare cause of growth failure, therefore it is uncertain whether routine screening with blood gas analysis of short infants and children is cost-effective.

OBJECTIVE

To investigate the clinical, growth and laboratory parameters in children with RTA to estimate the possible value of laboratory screening for this disorder in infants and children referred for short stature according to a recent guideline.

METHOD

Retrospective chart analysis of 30 children diagnosed between 1978 and 2005 in The Netherlands and 3 centers in Belgium.

RESULTS

The current guideline for short stature detected 33% of children with RTA. Assuming a pre-test probability of RTA of 0.6 per 100,000 births, the likelihood ratio of poor growth was 58 and 17 below and above 3 years, respectively. Sensitivity was 17/30 and 12/24 for a -2.0 SDS cutoff for weight and body mass index, respectively. In infants and toddlers diagnosed before 3 years of age, the mean weight loss was 1.5 SD, and 0.8 SDS in older children. In short children >3 years RTA was extremely rare, always associated with clinical symptoms, and rarely detected by blood gas analysis.

CONCLUSION

According to our data a decreasing weight SDS for age is a sufficient indication to perform blood gas analysis in children <3 years of age, particularly in the presence of additional clinical features, whereas it can be omitted in short children >3 years of age.

Genetic evaluation of short stature

After a proper medical history, growth analysis and physical examination of a short child, followed by radiological and laboratory screening, the clinician may decide to perform genetic testing. We propose several clinical algorithms that can be used to establish the diagnosis. GH1 and GHRHR should be tested in children with severe isolated growth hormone deficiency and a positive family history. A multiple pituitary dysfunction can be caused by defects in several genes, of which PROP1 and POU1F1 are most common. GH resistance can be caused by genetic defects in GHR, STAT5B, IGF1, IGFALS, which all have their specific clinical and biochemical characteristics. IGF-I resistance is seen in heterozygous defects of the IGF1R. If besides short stature additional abnormalities are present, these should be matched with known dysmorphic syndromes. If no obvious candidate gene can be determined, a whole genome approach can be taken to check for deletions, duplications and/or uniparental disomies.

The severe short stature in two siblings with a heterozygous IGF1 mutation is not caused by a dominant negative effect of the putative truncated protein

OBJECTIVE

While in previous studies heterozygosity for an Insulin-Like Growth Factor 1 (IGF1) defect only modestly decreased height and head circumference, we recently reported on two siblings with severe short stature with a maternally transmitted heterozygous duplication of 4 nucleotides, resulting in a frame shift and a premature termination codon in the IGF1 gene. In this paper we describe the structural and functional characteristics of the putative truncated IGF-I protein.

DESIGN

Two children, their mother and maternal grandfather carried the mutation. In addition, two family members who were not affected were included in the study. Mutant (MT) IGF-I was synthesized in oxidized and reduced form using two methods. Neutral gel filtration studies were carried out with wild-type (WT) and synthetic MT IGF-I. Binding analysis of synthetic MT IGF-I to the IGF1R and insulin receptors were performed with EBNA-293 cells, stably transfected with the IGF-I receptor, and IM9 cells. L6 cells were used to examine the mitogenic potency and the potential antagonizing effect of synthetic MT IGF-I by [(3)H]-thymidine incorporation assays.

RESULTS

In the sera of both the carriers and non-carriers the proportion of (125)I-IGF-I that was associated with the 150 kDa complex was somewhat less (varying between ~37 and ~52%) than in normal pooled serum (~53-~63%) and, instead, slightly increased amounts of radioactivity were eluted in the 40-50 kDa fraction (consisting of binary IGF-IGFBP complexes) or remained unbound. Synthetic MT IGF-I did not bind to the IGF-I receptor, nor antagonize the growth-promoting effect of IGF-I. It did bind to IGFBPs, but was barely incorporated into 150 kDa complexes. Because in all cases WT IGF-I immunoreactivity was recovered in one peak, corresponding to the MW of WT IGF-I, i.e. ~7.6 kDa, an interaction of circulating truncated mutant peptide with WT IGF-I is very unlikely.

CONCLUSIONS

There is no evidence that the severe short stature associated with heterozygosity for this novel IGF1 mutation in children born from a mother with the same mutation is caused by a dominant negative effect of the truncated protein. We speculate that the growth failure is caused by a combination of partial IGF-I deficiency, placental IGF-I insufficiency, and other genetic factors.

Short stature associated with a novel heterozygous mutation in the insulin-like growth factor 1 gene

CONTEXT

Homozygous IGF1 deletions or mutations lead to severe short stature, deafness, microcephaly, and mental retardation. Heterozygosity for an IGF-I defect may modestly decrease height and head circumference.

OBJECTIVE

The objective of the study was to investigate the clinical features of heterozygous carriers of a novel mutation in the IGF1 gene in comparison with noncarriers in a short family and to establish the effect of human GH treatment.

SUBJECTS

Two children, their mother, and their maternal grandfather carried the mutation and were compared with two relatives who were noncarriers.

RESULTS

The two index cases had severe short stature (height sd score -4.1 and -4.6), microcephaly, and low IGF-I levels. Sequencing of IGF1 revealed a heterozygous duplication of four nucleotides, resulting in a frame shift and a premature termination codon. The mother and maternal grandfather had the same IGF1 mutation. Adult height (corrected for shrinking and secular trend) and head circumference sd score of carriers of the paternally transmitted mutation was -2.5 and -1.8, in comparison with -1.6 and 0.3 in noncarriers, respectively. After 2 yr of GH treatment, both index cases exhibited increased growth.

CONCLUSIONS

Heterozygosity for this novel IGF1 mutation in children born from a mother with the same mutation, presumably in combination with other genetic factors for short stature, leads to severe short stature, which can be successfully treated with GH.

High-dose GH treatment limited to the prepubertal period in young children with idiopathic short stature does not increase adult height

OBJECTIVE

To assess the long-term effect of prepubertal high-dose GH treatment on growth in children with idiopathic short stature (ISS).

DESIGN AND METHODS

Forty children with no signs of puberty, age at start 4-8 years (girls) or 4-10 years (boys), height SDS <-2.0 SDS, and birth length >-2.0 SDS, were randomly allocated to receive GH at a dose of 2 mg/m(2) per day (equivalent to 75 microg/kg per day at start and 64 microg/kg per day at stop) until the onset of puberty for at least 2 years (preceded by two 3-month periods of treatment with low or intermediate doses of GH separated by two washout periods of 3 months) or no treatment. In 28 cases, adult height (AH) was assessed at a mean (S.D.) age of 20.4 (2.3) years.

RESULTS

GH-treated children (mean treatment period on high-dose GH 2.3 years (range 1.2-5.0 years)) showed an increased mean height SDS at discontinuation of the treatment compared with the controls (-1.3 (0.8) SDS versus -2.6 (0.8) SDS respectively). However, bone maturation was significantly accelerated in the GH-treated group compared with the controls (1.6 (0.4) versus 1.0 (0.2) years per year, respectively), and pubertal onset tended to advance. After an untreated interval of 3-12 years, AH was -2.1 (0.7) and -1.9 (0.6) in the GH-treated and control groups respectively. Age was a positive predictor of adult height gain.

CONCLUSION

High-dose GH treatment restricted to the prepubertal period in young ISS children augments height gain during treatment, but accelerates bone maturation, resulting in a similar adult height compared with the untreated controls.

Impact of the exon 3-deleted growth hormone (GH) receptor polymorphism on baseline height and the growth response to recombinant human GH therapy in GH-deficient (GHD) and non-GHD children with short stature: a systematic review and meta-analysis

CONTEXT

The exon-3 deleted GH receptor (GHR(d3)) polymorphism is associated with an increased growth response to recombinant human GH (rhGH) therapy in some, but not all, studies in GH-deficient (GHD) and non-GHD children with short stature.

OBJECTIVE

The aim of the study was to assess the effects of GHR(d3) on baseline height and the first year's growth response to rhGH treatment in prepubertal GHD and non-GHD children with short stature.

DESIGN

We conducted a systematic review and meta-analysis.

METHODS

Fifteen studies reporting the effect of GHR(d3) on growth parameters were included. Principal outcomes were baseline height sd score (SDS) and the weighted average of change in growth velocity (Delta cm/yr) and height gain (Delta height SDS) after 1 yr of rhGH.

RESULTS

In GHD, not in non-GHD, baseline height SDS was 0.159 sd higher [95% confidence interval (CI), 0.020, 0.298] in GHR(d3) compared with GHR(wt-wt). In GHR(d3), rhGH therapy resulted in a higher increase in growth velocity (0.521 cm/yr; 95% CI, 0.196, 1.015) and height gain (0.075 sd; 95% CI, 0.007, 0.143) compared with GHR(wt-wt). Meta-regression demonstrated a larger difference between GHR(d3) and GHR(wt-wt) in studies using lower rhGH doses and carried out at a higher age, independently of the cause of short stature.

CONCLUSIONS

This meta-analysis in prepubertal children with short stature indicates that GHR(d3) is associated with increased baseline height in GHD, but not in non-GHD. Furthermore, GHR(d3) stimulates growth velocity by an additional effect of approximately 0.5 cm during the first year of rhGH treatment, and this effect is more pronounced at lower doses of rhGH and higher age.

A case of premature thelarche with no central cause or genetic variants within the estrogen receptor signaling pathway

BACKGROUND

Premature thelarche is defined as breast development before 8 years of age. This is most often caused by central hormone disregulation and is accompanied by concurrent bone maturation. However, we present a case of premature thelarche with concurrent bone maturation without central hormone disregulation. Genes within the estrogen signaling pathway were examined for genetic changes which might be responsible for the clinical phenotype.

PATIENT REPORT

A girl presented with breast development from 18 months of age with undetectable serum estrogens, prepubertal serum gonadotropins, advanced growth and skeletal maturation, but no increase of uterine size, thus presenting a premature thelarche variant. Serum estrogens remained below detectable limits until she entered into an unremarkable puberty at 12.1 years of age. No abnormalities or SNPs were found in the genes tested.

CONCLUSION

We describe a case of premature thelarche which cannot be attributed to a central cause of abnormal hormone levels or to alterations in genes suspected for this phenotype. We conclude that other yet to be identified factors are involved in this unique case of premature thelarche.

Intelligence of very preterm or very low birthweight infants in young adulthood

OBJECTIVE

To examine the effect of intrauterine and neonatal growth, prematurity and personal and environmental risk factors on intelligence in adulthood in survivors of the early neonatal intensive care era.

METHODS

A large geographically based cohort comprised 94% of all babies born alive in the Netherlands in 1983 with a gestational age below 32 weeks and/or a birth weight >1500 g (POPS study). Intelligence was assessed in 596 participants at 19 years of age. Intrauterine and neonatal growth were assessed at birth and 3 months of corrected age. Environmental and personal risk factors were maternal age, education of the parent, sex and origin.

RESULTS

The mean (SD) IQ of the cohort was 97.8 (15.6). In multiple regression analysis, participants with highly educated parents had a 14.2-point higher IQ than those with less well-educated parents. A 1 SD increase in birth weight was associated with a 2.6-point higher IQ, and a 1-week increase in gestational age was associated with a 1.3-point higher IQ. Participants born to young mothers (<25 years) had a 2.7-point lower IQ, and men had a 2.1-point higher IQ than women. The effect on intelligence after early (symmetric) intrauterine growth retardation was more pronounced than after later (asymmetric) intrauterine or neonatal growth retardation. These differences in mean IQ remained when participants with overt handicaps were excluded.

CONCLUSIONS

Prematurity as well as the timing of growth retardation are important for later intelligence. Parental education, however, best predicted later intelligence in very preterm or very low birthweight infants.

No change in developmental outcome with incubator covers and nesting for very preterm infants in a randomised controlled trial

OBJECTIVE

To investigate in a randomised controlled trial the effect of basic elements of developmental care (incubator covers and positioning aids) on growth and neurodevelopment in infants born at < 32 weeks.

METHOD

Infants were randomised within 48 h of birth to a developmental care (DC) or standard care (C) group. Outcome measures at 1 and 2 years corrected age were growth, standardised neurological examinations, and mental (MDI) and psychomotor (PDI) development (Dutch version of the Bayley Scales of Infant Development II).

RESULTS

192 infants were recruited (DC = 98; C = 94). Thirteen infants (DC = 7, C = 6) were excluded because they were admitted for <5 days or died within the first 5 days. In total, 179 infants met the inclusion criteria. In-hospital mortality was 12/91 (13.2%) in the DC group and 8/88 (9.1%) in the C group. Assessments were carried out on 147 children (DC = 74, C = 73) at 1 year and 142 children (DC = 72, C = 70) at 2 years. No significant difference in growth, neurological outcomes or MDI was found. A positive trend in PDI at 1 year (p = 0.05) did not continue once the children reached 2 years. There was no difference found when neurological and developmental scores were combined.

CONCLUSIONS

Basic developmental care has no positive effect on neurological and mental development or growth at 1 and 2 years of age in infants born at <32 weeks. A positive effect on psychomotor development at 1 year did not continue at 2 years of age.

Antenatal glucocorticoid treatment is not associated with long-term metabolic risks in individuals born before 32 weeks of gestation

BACKGROUND

A single course of maternal glucocorticoid treatment is effective in reducing neonatal mortality after preterm birth. However, in animals, maternal glucocorticoid treatment is associated with lifelong hyperglycaemia and hypertension, and impaired nephrogenesis in offspring. Findings from studies in humans on this topic are highly contradictory due to a number of methodological flaws, and renal function after glucocorticoid exposure has never been assessed.

OBJECTIVES

To assess in individuals born <32 gestational weeks whether antenatal glucocorticoid treatment for preterm birth is associated with long-term metabolical risks, including renal function, in adulthood.

DESIGN

Birth cohort study.

SETTING

Multicentre study.

PATIENTS

412 19 year olds born <32 gestational weeks from the Project On Preterm and Small-for-gestational-age infants (POPS) cohort.

INTERVENTIONS

Maternal betamethasone 12 mg administered twice with a 24 h interval.

MAIN OUTCOME MEASURES

Body composition, insulin resistance, the serum lipid profile, blood pressure and estimated renal function.

RESULTS

We did not find any long-term adverse effects of antenatal betamethasone, with the exception of an effect on glomerular filtration rate (GFR). In 19-year-old survivors, GFR was lower after betamethasone: -5.2 ml/min (95% CI -8.9 to -1.4) per 1.73 m(2).

CONCLUSIONS

The reduction in neonatal mortality associated with a single course of maternal betamethasone is not accompanied by long-term metabolical risks in survivors of preterm birth. The only adverse effect found was lower GFR. Although this difference was not clinically relevant at 19 years, it might predict an increased risk of chronic renal failure in prematurely born individuals who were exposed antenatally to betamethasone.

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.

Growth of preterm born children

BACKGROUND

In this review, we describe the growth of (very) preterm infants or (very) low-birth-weight infants from birth until adulthood.

METHODS

A systematic analysis of growth of these infants is thwarted by different definitions (classification by gestational age or birth weight) used in the literature.

RESULTS

The early postnatal period of these individuals is almost invariably characterized by substantial growth failure. In the majority of preterm infants this is followed by a period of catch-up growth, which starts in early infancy and usually stops at 2-3 years of age, although in some cases it may continue into adolescence. Catch-up growth is usually incomplete, so that infants born preterm remain shorter and lighter than term-born peers during childhood, adolescence, and adulthood. Disproportionate catch-up growth in height and weight may lead to an altered body composition in adulthood, especially in females.

CONCLUSION

Though early catch-up growth has shown to be beneficial for neurodevelopmental outcome, it is also associated with adverse metabolic consequences in adulthood. As the first generation of (very) preterm infants is now reaching young adulthood, future follow-up studies on these effects are warranted.

Health-related quality of life of very preterm infants at 1 year of age after two developmental care-based interventions

BACKGROUND

In the context of a growing interest in developmental care (DC) this study explores the effect of the basic elements of DC and the additional effect of the individual approach of the Newborn Individualized Developmental Care and Assessment Program (NIDCAP) on the health-related quality of life (HRQoL) of very preterm infants at 1 year of age. The basic elements of DC in this study were defined as the use of standardized nests and incubator covers whose protective characteristics were hypothesized to have a positive effect on the infant's HRQoL. The individualized approach of the NIDCAP was thought to further increase HRQoL.

METHODS

Very preterm (<or=32 weeks) born infants in a Dutch Neonatal Intensive Care Unit at two locations were included in two consecutive randomized controlled trials (RCT) comparing controls (standard care) with basic DC (standardized nests and covers) in the first RCT and basic DC with NIDCAP in the second RCT. Parents completed a questionnaire (RCT 1, n=136; RCT 2, n=128) regarding their infant's HRQoL (TNO-AZL Preschool Quality of Life Questionnaire) at 1 year of age, corrected for prematurity. Because of multiple testing a P-value of below 0.01 was chosen to indicate significance.

RESULTS

HRQoL scores ranged from good to optimal for most infants. No significant differences were found between basic DC vs. controls and NIDCAP vs. basic DC on the child's HRQoL as reported by parents at 1 year of age.

CONCLUSIONS

These two RCT show that the basic elements of DC and the more individualized NIDCAP do not improve HRQoL of very preterm infants at 1 year of age.

Homozygous and heterozygous expression of a novel mutation of the acid-labile subunit

CONTEXT

Acid-labile subunit (ALS) deficiency due to homozygous inactivation of the ALS gene (IGFALS) is associated with moderate short stature, and in few cases pubertal delay. The clinical expression of heterozygosity is unknown.

OBJECTIVE

To investigate the clinical, laboratory, and radiological features of homozygous and heterozygous carriers of a novel mutation in the ALS gene in comparison with non-carriers.

SUBJECTS

Three short Kurdish brothers and their relatives.

RESULTS

The index cases presented with short stature, microcephaly, and low circulating IGF-I and IGF-binding protein-3 (IGFBP-3), and undetectable ALS levels. Two were known with a low bone mineral density and one of them had suffered from two fractures. We found a novel homozygous ALS gene mutation resulting in a premature stop codon (c.1490dupT, p.Leu497PhefsX40). The IGF-I, IGFBP-3, and ALS 150 kDa ternary complex was absent, and ALS proteins in serum were not detected with western blot. IGFPB-1 and IGFPB-2 were low and there was a mild insulin resistance. Five heterozygous carriers tended to have a lower height and head circumference than five non-carriers, and had low plasma ALS and IGFBP-3 levels. Bone mineral (apparent) density was low in two out of three homozygous carriers, and also in four out of nine relatives.

CONCLUSIONS

The clinical presentation of homozygous ALS mutations may, besides short stature, include microcephaly. Heterozygous carriers may have less statural and head growth, suggestive for a gene dosage effect.

Mental and motor development before and during growth hormone treatment in infants and toddlers with Prader-Willi syndrome

BACKGROUND

Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, feeding difficulties and failure to thrive in infancy. GH treatment improves growth velocity and body composition. Research on the effects of GH on psychomotor development in infants with PWS is limited.

OBJECTIVE

To evaluate psychomotor development in PWS infants and toddlers during GH treatment compared to randomized controls.

DESIGN/PATIENTS

Forty-three PWS infants were evaluated at baseline. Twenty-nine of them were randomized into a GH group (n = 15) receiving 1 mg/m(2)/day GH or a non-GH-treated control group (n = 14). At baseline and after 12 months of follow-up, analysis with Bayley Scales of Infant Development II (BSID-II) was performed. Data were converted to percentage of expected development for age (%ed), and changes during follow-up were calculated.

RESULTS

Infants in the GH group had a median age of 2.3 years [interquartile range (IQR) 1.7-3.0] and in the control group of 1.5 years (IQR 1.2-2.7) (P = 0.17). Both mental and motor development improved significantly during the first year of study in the GH group vs. the control group: median (IQR) change was +9.3% (-5.3 to 13.3) vs.-2.9% (-8.1 to 4.9) (P < 0.05) in mental development and +11.2% (-4.9 to 22.5) vs.-18.5% (-27.9 to 1.8) (P < 0.05) in motor development, respectively.

CONCLUSION

One year of GH treatment significantly improved mental and motor development in PWS infants compared to randomized controls.

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.

Developing evidence-based guidelines for referral for short stature

OBJECTIVE

To establish evidence-based guidelines for growth monitoring on a population basis.

STUDY DESIGN

Several auxological referral criteria were formulated and applied to longitudinal growth data from four different patient groups, as well as three samples from the general population.

RESULTS

Almost 30% of pathology can be detected by height standard deviation score (HSDS) below -3 or at least two observations of HSDS below -2.5 at a low false-positive rate (<1%) in 0-3-year-old infants. For 3-10-year olds, a rule concerning distance to target height of >2 SD in combination with HSDS <-2.0 has the best predictive value. In combination with a rule on severe short stature (<-2.5 SDS) and a minor contribution from a rule on "height deflection", 85.7% of children with Turner syndrome and 76.5% of children who are short because of various disorders are detected at a false-positive rate of 1.5-2%.

CONCLUSIONS

The proposed guidelines for growth monitoring show high sensitivity at an acceptably low false-positive rate in 3-10-year-old children. Distance to target height is the most important criterion. Below the age of 3 years, the sensitivity is considerably lower. The resulting algorithm appears to be suitable for industrialised countries, but requires further testing in other populations.

Parental experiences during the first period at the neonatal unit after two developmental care interventions

AIM

Developmental care has gained increased attention in the individualized care for preterm infants. This study was designed to explore the effect of a basic form of developmental care and the more extended Newborn Individualized Developmental Care and Assessment Program (NIDCAP) on parental stress, confidence and perceived nursing support.

METHODS

Two consecutive randomized controlled trials (RCT's) comparing (1) standard care versus basic developmental care (standardized nests and incubator covers) (n = 133) and (2) basic developmental care versus NIDCAP, including behavioural observations (n = 150). Parents of infants born <32 weeks gestational age (GA) received questionnaires after the first week of admission in the neonatal unit and on average these 2 weeks after the birth of their infant.

RESULTS

No significant differences were found in confidence, perceived nursing support or parental stress. The difference in parental stress between mother and father was less in the NIDCAP intervention group (p = .03), although not significant.

CONCLUSION

Both basic developmental care and NIDCAP had little effect on parental experiences during the first period at the neonatal unit. As a result of increased paternal stress, the NIDCAP intervention tended to decrease the difference in parental stress levels of fathers and mothers, possibly because of the increased involvement of father during the NIDCAP intervention.

Growth hormone (GH) secretion and response to GH therapy after total body irradiation and haematopoietic stem cell transplantation during childhood

OBJECTIVE

In January 1997 we introduced a protocol for the treatment with GH of children with impaired growth after unfractionated total body irradiation (TBI). This study is an evaluation of that protocol.

PATIENTS AND METHODS

Between January 1997 and July 2005, 66 patients (48 male) treated for haematological malignancies had at least two years of disease-free survival after TBI-based conditioning for stem cell transplantation (SCT). Stimulated and/or spontaneous GH secretion was decreased in 8 of the 29 patients tested because of impaired growth. Treatment with GH (daily dose 1.3 mg/m2 body surface area) was offered to all 29 patients and initiated in 23 of them (17 male). The main outcome measure was the effect of GH therapy on height standard deviation scores (SDS) after onset of GH therapy, estimated by random-effect modelling with corrections for sex, age at time of SCT and puberty (data analysed on intention-to-treat basis).

RESULTS

At time of analysis, median duration of therapy was 3.2 years; median follow-up after start of GH therapy was 4.2 years. The estimated effect of GH therapy, modelled as nonlinear (logit) curve, was +1.1 SD after 5 years. Response to GH therapy did not correlate to GH secretion status.

CONCLUSION

GH therapy has a positive effect on height SDS after TBI, irrespective of GH secretion status.

Radiographic Evaluation of Children with Growth Disorders

Short stature as well as tall stature can have a wide variety of causes. Tall stature is usually experienced as a less important problem than short stature, but for both clinical presentations it is important to make a correct diagnosis as to etiology. The identification of the diagnosis frequently relies on radiological criteria. However, no international uniformity exists with respect to the radiographic evaluation of children with growth problems. We recommend that in patients with a possible diagnosis of a skeletal dysplasia a skeletal survey must be performed. In patients with a proportionate stature, radiographic analysis of the hand and wrist will be sufficient in most cases. However, whenever there are clinical abnormalities with a possible underlying bone anomaly, a modified skeletal survey is appropriate. The combination of clinical and biochemical features and an appropriate skeletal survey can often lead to the correct diagnosis and/or guide the subsequent molecular analysis.

Thyroid hormone levels in children with Prader-Willi syndrome before and during growth hormone treatment

BACKGROUND

Prader-Willi syndrome (PWS) is a neurogenetic disorder characterized by muscular hypotonia, psychomotor delay, obesity and short stature. Several endocrine abnormalities have been described, including GH deficiency and hypogonadotrophic hypogonadism. Published data on thyroid hormone levels in PWS children are very limited.

OBJECTIVE

To evaluate thyroid function in children with PWS, before and during GH treatment.

DESIGN/PATIENTS

At baseline, serum levels of T4, free T4 (fT4), T3, reverse T3 (rT3) and TSH were assessed in 75 PWS children. After 1 year, assessments were repeated in 57 of the them. These children participated in a randomized study with two groups: group A (n = 34) treated with 1 mg GH/m(2)/day and group B (n = 23) as controls.

RESULTS

Median age (interquartile range, IQR) of the total group at baseline was 4.7 (2.7-7.6) years. Median (IQR) TSH level was -0.1 SDS (-0.5 to 0.5), T4 level -0.6 SDS (-1.7 to 0.0) and fT4 level -0.8 SDS (-1.3 to -0.3), the latter two being significantly lower than 0 SDS. T3 level, at 0.3 SDS (-0.3 to 0.9), was significantly higher than 0 SDS. After 1 year of GH treatment, fT4 decreased significantly from -0.8 SDS (-1.5 to -0.2) to -1.4 SDS (-1.6 to -0.7), compared to no change in untreated PWS children. However, T3 did not change, at 0.3 SDS (-0.1 to 0.8).

CONCLUSIONS

We found normal fT4 levels in most PWS children. During GH treatment, fT4 decreased significantly to low-normal levels. TSH levels remained normal. T3 levels were relatively high or normal, both before and during GH treatment, indicating that PWS children have increased T4 to T3 conversion.

Genetic disorders in the GH IGF-I axis in mouse and man

Animal knockout experiments have offered the opportunity to study genes that play a role in growth and development. In the last few years, reports of patients with genetic defects in GH-IGF-I axis have greatly increased our knowledge of genetically determined causes of short stature. We will present the animal data and human reports of genetic disorders in the GH-IGF-I axis in order to describe the role of the GH-IGF-I axis in intrauterine and postnatal growth. In addition, the effects of the GH-IGF-I axis on the development and function of different organ systems such as brain, inner ear, eye, skeleton, glucose homeostasis, gonadal function, and immune system will be discussed. The number of patients with genetic defects in the GH-IGF-I axis is small, and a systematic diagnostic approach and selective genetic analysis in a patient with short stature are essential to identify more patients. Finally, the implications of a genetic defect in the GH-IGF-I axis for the patient and the therapeutic options will be discussed.

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.

Novel mutations in the parathyroid hormone (PTH)/PTH-related peptide receptor type 1 causing Blomstrand osteochondrodysplasia types I and II

CONTEXT

The PTH/PTHrP receptor type 1 (PTHR1) has a key role in endochondral ossification, which is emphasized by diseases resulting from mutations in the PTHR1 gene. Among these diseases is Blomstrand osteochondrodysplasia (BOCD).

OBJECTIVE

BOCD can be divided into two types, depending on the severity of the skeletal abnormalities. The molecular basis for this heterogenic presentation is unknown.

DESIGN AND PATIENTS

We performed mutation analysis in two families with type I and in three families with the less severe form of BOCD type II.

RESULTS

In one of the type I BOCD cases, a homozygous nonsense mutation (R104X) was found, resulting in a truncated PTHR1. In the second type I BOCD case, no mutation was found. A homozygous nucleotide change (intron M4+27C>T) was demonstrated in one of the type II BOCD cases creating a novel splice site. In dermal fibroblasts of the patient, this novel splice site was preferentially used, resulting in an aberrant transcript. The wild-type transcript remained, however, present, albeit at low levels. In the other two families with type II BOCD, a previously identified homozygous missense mutation (P132L) was found. Functional analysis demonstrated that the P132L mutant had low residual activity.

CONCLUSIONS

In combination with data presented in literature, we conclude that type I BOCD is caused by a complete inactivation of the PTHR1, whereas low levels of residual activity due to a near complete inactivation of the PTHR1 result in the relatively milder presentation of type II BOCD.