Genetic factors associated with small for gestational age birth and the use of human growth hormone in treating the disorder

Factors affecting growth hormone treatment in short stature children born small for gestational age in China: a single-centre, real-world study

PURPOSE

The study aimed to evaluate the factors influencing recombinant human growth hormone (rhGH) treatment in Chinese children with short stature born small for gestational age (SGA).

METHODS

A single-centre, real-world retrospective study was conducted in short stature children born SGA in China. Outcomes were observed at 6, 12, 18, 24, 30, and 36 months. Outcome measures included height standard deviation score (HTSDS), height, growth velocity (GV), and change of HTSDS (ΔHTSDS). The study used the generalized estimating equation (GEE) to identify potential influencing factors, such as rhGH treatment duration, age at rhGH initiation, sex, 11p15 hypomethylation, GH secretion, and birth weight. A subgroup analysis was conducted to investigate the impact of 11p15 hypomethylation related to SGA or impaired GH secretion.

RESULTS

Of all 101 SGA patients included in the screening, 41 were eligible for inclusion in the study. The mean age at rhGH initiation was 5.6 ± 2.4 years. The results of the GEE analysis showed a significant association between time after rhGH initiation and HTSDS, height, GV, and ΔHTSDS. GV increased after treatment, with the highest increase observed in the first six months. Additionally, the study found negative correlations between 11p15 hypomethylation and GV, as well as between birth weight and both GV and ΔHTSDS. The study found a positive correlation between impairment in GH secretion and both GV and ΔHTSDS. No statistically significant difference was observed in the comparison of GV or ΔHTSDS between the initiation age of GH treatment and 11p15 hypomethylation. After 24 and 30 months of rhGH treatment, patients with impaired GH secretion had significantly higher ΔHTSDS scores.

CONCLUSIONS

In short stature Chinese children born SGA, those without SGA-related 11p15 hypomethylation or with impaired GH secretion showed better response to rhGH treatment. These findings highlight the importance of pre-treatment evaluation, including genetic and endocrine assessments.

The Exon 3-Deleted Growth Hormone Receptor (d3GHR) Polymorphism-A Favorable Backdoor Mechanism for the GHR Function

Growth hormone (GH) is a peptide hormone that plays a crucial role in controlling growth, development, and lifespan. Molecular regulation of GH is accomplished via the GH receptor (GHR), which is the main factor influencing human development and is essential to optimal functioning of the GH/IGF-I axis. Two GHR isoforms have been studied, according to the presence (flGHR) or absence (d3GHR) of exon 3. The d3GHR isoform, which lacks exon 3 has recently been related to longevity; individuals carrying this isoform have higher receptor activity, improved signal transduction, and alterations in the treatment response and efficacy compared with those carrying the wild type (WT) isoform (flGHR). Further, studies performed in patients with acromegaly, Prader-Willi syndrome, Turner syndrome, small for gestational age (SGA), and growth hormone deficiency (GHD) suggested that the d3GHR isoform may have an impact on the relationship between GH and IGF-I levels, height, weight, BMI, and other variables. Other research, however, revealed inconsistent results, which might have been caused by confounding factors, including limited sample sizes and different experimental methods. In this review, we lay out the complexity of the GHR isoforms and provide an overview of the major pharmacogenetic research conducted on this ongoing and unresolved subject.

The Role of Insulin-like Growth Factor-Axis and Mitotic Index in South Indian Neonates with Small for Gestational Age

OBJECTIVE

IGF-axis and mitotic capacity of cells play a vital role in fetal growth. We compared IGF1, IGF2, and IGFBP3 protein levels, mitotic indices, IGFR1 and IGFR2 mRNA expression in appropriate for gestational age (AGA) and small for gestational age (SGA) neonates of Indian women.

METHODS

Cord blood (n = 80) and placental samples (n = 40) were collected from AGA and SGA neonates. Plasma IGF1, IGF2, and IGFBP3 proteins were measured by ELISA. IGFR1 and IGFR2 mRNA expression in the placenta were analyzed by qRT-PCR. Cord blood was cultured in vitro and mitotic index was obtained.

RESULTS

IGF1 (p = 1), and IGF2 (p = 0.69) protein levels did not differ, whereas IGFBP3 (p = 0.02) was significantly less in SGA compared to AGA neonates. Down-regulation of IGFR1 (3.9-folds) and IGFR2 (2.8-folds) mRNA and reduced mitotic index of lymphocytes was observed in SGA (p = 0.001) compared to AGA neonates.

CONCLUSION

Our results showed that, SGA neonates displayed down-regulated IGFR1 and IGFR2 mRNA, decreased IGFBP3 protein and mitotic index.

Increase of jump performance during GH treatment in short children born SGA

Background

Short children born small for gestational age (SGA) often have low muscle mass. Studies on maximal isometric grip-force (MIGF) observed lower muscle strength in these children. In contrast to MIGF, jumping is an everyday muscle activity for children. Our hypothesis was that GH treatment would cause an increase in jumping strength. So, we aimed to study jumping by mechanography in short SGA children before and during GH treatment.

Methods

Monocentric prospective longitudinal study in a tertiary pediatric endocrinology center. We studied 50 prepubertal short children (23 females) born SGA (mean age 7.2 y, height -3.24 SDS) during GH treatment (mean dose 45 µg/kg/d). Main outcome measures were Peak jump force (PJF) and peak jump power (PJP) measured by Leonardo^® ground reaction force plate at baseline and after 12 months of GH treatment. Mechanography data were compared to sex, age and height related references (SD-Score). Fitness was estimated as PJP/kg body weight by use of the Esslinger-Fitness-Index (EFI).

Results

At start of GH treatment PJP/body weight was low at -1.52 SDS and increased significantly to -0.95 SDS during 12 months of treatment (p<0.001). PJF was low-normal compared to height dependent references and remained unchanged. PJP was normal compared to height dependent references and increased only slightly from -0.34 to -0.19 SDS_HT.

Conclusions

Jumping performance (EFI) measured by mechanography increased during one year of GH treatment in short children born SGA.

Catch-Up Growth as a Risk Factor for Rapid Weight Gain, Earlier Menarche and Earlier Pubertal Growth Spurt in Girls Born Small for Gestational Age (SGA)-A Longitudinal Study

Most children born small for gestational age (SGA) have rapid postnatal growth. Despite its positive aspects, catch-up growth may affect the level of adipose tissue in the pre-pubertal and pubertal periods and therefore affect the age of puberty. The aim of this study was to determine the associations between size at birth, catch-up growth in infancy, BMI in peripubertal period, age at menarche, and the parameters of adolescent growth spurt of body height in girls born SGA. For 297 girls (22.6% SGA; 77.4% appropriate for gestational age (AGA)) complete body weight and height measurements and age at menarche were obtained. Adolescent growth spurt parameters were estimated using the JPA2 model (AUXAL SSI 3.1). Calculations were made in the Statistica 13 program using the Kruskal-Wallis and Kaplan-Meier tests. Girls born SGA with catch-up had the highest BMIs at the age of 8 years (H = 94.22, p < 0.001) and at menarche (H = 58.21, p < 0.001), experienced menarche earliest (H = 21.77, p < 0.001), same as the onset (H = 6.54, p = 0.012) and peak height velocity (H = 11.71, p = 0.003) of their adolescent growth spurt compared to SGA girls without catch-up and AGA girls. In SGA girls, catch-up growth has far-reaching consequences such as increased risk of fat accumulation and a rapid transition to puberty.

Antenatal and neonatal factors contributing to extra uterine growth failure (EUGR) among preterm infants in Boston Birth Cohort (BBC)

OBJECTIVE

Identify antenatal and neonatal factors associated with primary outcome of EUGR.

METHODS

1063 preterm infants from a subset of the BBC were included in this prospective cohort study. Regression analysis was carried out to evaluate associations of EUGR with antenatal factors and neonatal factors.

RESULTS

6.1% of the infants had in-utero growth restriction (IUGR) at birth and 21.7% of infants had EUGR. The adjusted odds ratio for EUGR status were significant for birth weight (OR 0.99, p = 0.00, CI 0.99-0.99), for GA at birth (OR 4.58, p = 0.00, CI 3.25-6.44), for PDA (OR 2.9, p = 0.02, CI 1.17-7.1), for NEC (OR 5.14, p = 0.012, CI 1.44-18.3) and for day of life of reaching full feeds (OR 1.04, p = 0.001, CI 1.01-1.06).

CONCLUSION

This study highlights important factors associated with EUGR. Additional studies are needed to gain further insight.

The Impact of Gut Microbiome on Metabolic Disorders During Catch-Up Growth in Small-for-Gestational-Age

OBJECTIVE

Catch-up growth (CUG) in small for gestational age (SGA) leads to increased risk of metabolic syndrome and cardiovascular diseases in adults. It remains unclear if microbiota could play an important role in CUG-SGA independent of genetic or nutritional factors. The present study explored the role of gut microbiota in, and its association with, metabolic disorders during CUG-SGA.

METHODS

An SGA rat model was established by restricting food intake during pregnancy, and the rats were divided into catch-up growth (CUG-SGA) and non-catch-up growth (NCUG-SGA) groups based on body weight and length at the fourth postnatal week. High-throughput sequencing of 16S rRNA was conducted to detect the diversity and composition of the gut microbiota. Fecal short-chain fatty acids (SCFAs) were detected by gas chromatography-mass spectrometry. Transcriptome sequencing of liver tissue was performed and verified using real-time PCR. Concentrations of insulin and total cholesterol were determined using enzyme-linked immunosorbent assay.

RESULTS

The composition of gut microbiota in CUG-SGA rats differed from that of NCUG-SGA rats, with reduced abundance of Lactobacillus in the CUG-SGA group. The decrease in Lactobacillus was significantly associated with increased body weight and upregulated insulin and total cholesterol levels. Five SCFAs and two branched chain fatty acids were significantly higher in the CUG-SGA group than in the NCUG-SGA group. Additionally, SCFAs were positively associated with clinical indices such as weight, body mass index, insulin, and total cholesterol. Transcriptomic data revealed that insulin-like growth factor-2 expression was significantly decreased in CUG-SGA rats and was associated with a decrease in Lactobacillus bacteria.

CONCLUSION

Lactobacillus and SCFAs were associated with the metabolic disorders during CUG in SGA. Gut microbiome may play a certain role on metabolic disorders during catch-up growth in small-for-gestational-age.

Genetic Screening for Growth Hormone Therapy in Children Small for Gestational Age: So Much to Consider, Still Much to Discover

Children born small for gestational age (SGA), and failing to catch-up growth in their early years, are a heterogeneous group, comprising both known and undefined congenital disorders. Care for these children must encompass specific approaches to ensure optimal growth. The use of recombinant human growth hormone (rhGH) is an established therapy, which improves adult height in a proportion of these children, but not with uniform magnitude and not in all of them. This situation is complicated as the underlying cause of growth failure is often diagnosed during or even after rhGH treatment discontinuation with unknown consequences on adult height and long-term safety. This review focuses on the current evidence supporting potential benefits from early genetic screening in short SGA children. The pivotal role that a Next Generation Sequencing panel might play in helping diagnosis and discriminating good responders to rhGH from poor responders is discussed. Information stemming from genetic screening might allow the tailoring of therapy, as well as improving specific follow-up and management of family expectations, especially for those children with increased long-term risks. Finally, the role of national registries in collecting data from the genetic screening and clinical follow-up is considered.

The impact of anti-tobacco legislation on birth weight in Peru

Background

Tobacco exposure remains a significant issue for public health, especially for pregnant women. It increases the risk for premature labor, low birth weight and small for gestational age (SGA), among other effects. To reduce these risks, many countries have enacted public policies to curb tobacco exposure. Peru enacted anti-tobacco laws that forbid smoking in public places, require prevention text and images in products and publicity, along with restriction of sales to adults. We evaluated the effect of the implementation of this law on newborn outcomes: birth weight, prematurity and SGA.

Methods

This was a quasi-experimental study that utilized data from the Peruvian Live Birth Registry. Children born to mothers from urban areas were the intervention group, while children born to mothers from rural areas were considered the control group. Only singletons with information on birth weight and gestational age, born to mothers aged 12 to 49 years were included in the study. In addition, newborns with birth weights greater than + 4 standard deviations (SD) or less than - 4 SD from the gestational age-specific mean were excluded. To measure the effect of legislation on birth weight we performed a difference in differences analysis.

Results

A total of 2,029,975 births were included in the analysis. After adjusting for characteristics of the mother and the child, and contextual variables, the anti-tobacco law in Peru reduced the incidence of prematurity by 30 cases per 10,000 live births (95% CI: 19 to 42).

Conclusions

The reform had negligible effects on overall birth weights and on the incidence of SGA. This modest result suggests the need for a more aggressive fight against tobacco, prohibiting all types of advertising and promotion of tobacco products, among others measures.

Modulation of Placental Gene Expression in Small-for-Gestational-Age Infants

Small-for-gestational-age (SGA) infants are fetuses that have not reached their genetically programmed growth potential. Low birth weight predisposes these infants to an increased risk of developing cardiovascular, metabolic and neurodevelopmental conditions in later life. However, our understanding of how this pathology occurs is currently incomplete. Previous research has focused on understanding the transcriptome, epigenome and bacterial signatures separately. However, we hypothesise that interactions between moderators of gene expression are critical to understanding fetal growth restriction. Through a review of the current literature, we identify that there is evidence of modulated expression/methylation of the placental genome and the presence of bacterial DNA in the placental tissue of SGA infants. We also identify that despite limited evidence of the interactions between the above results, there are promising suggestions of a relationship between bacterial signatures and placental function. This review aims to summarise the current literature concerning fetal growth from multiple avenues and propose a novel relationship between the placental transcriptome, methylome and bacterial signature that, if characterised, may be able to improve our current understanding of the placental response to stress and the aetiology of growth restriction.

IGF1R Gene Alterations in Small for Gestational Age (SGA) Children

BACKGROUND

Small for gestational age children (SGA) is born on term with BW and or BL of -2.0 standard deviation score (SDS). SGA children have an increased risk of being short, developing DM, and cardiovascular and cerebrovascular disease. Often defects of IGF1R are the cause of SGA. Most frequently affected part of the IGF1R gene is the exon 2.

AIM

To investigate whether the exon 2 of the IGF1R gene is affected in the SGA children.

PATIENTS AND METHODS

A cohort of 100 SGA children born in term was evaluated for alterations in IG1R gene. Their anthropometric parameters, IGF1 serum concentrations and IGF1 SDS values were analysed. The molecular analysis of IGF1R gene was performed by PCR restriction-site analysis and followed by direct sequencing of conspicuous fragments.

RESULTS

Within our cohort, 64 SGA children were with short stature (height SDS -3.25 ± 0.90 SDS), and 36 were with normal height for their age and sex, (H SDS was 0.20 ± 1.1 SDS). None of these children had microcephaly (occipitofrontal circumference -0.70 ± 1.01 SDS vs 0.06 ± 0.56 SDS in SGA children with normal height) or dysmorphic features. The IGF1 serum concentrations and IGF1 SDS values of all children were within normal range. Only one child had lower normal serum IGF1 concentration. No alterations in exon 2 of IGF1R gene were detected.

CONCLUSIONS

The genetic analysis of the exon 2 of the IGF1R gene did not detect any gene defects in the analysed patients. The putative genetic defect in those children affects other parts of the IGF1R gene or another gene (s), or yet unidentified factors.

Diagnosis and management of growth disorders in Gulf Cooperation Council (GCC) countries: Current procedures and key recommendations for best practice

Diagnosis and management of growth disorders comprises an important area of pediatric practice. Current procedures in the different stages of the identification, referral, investigation, and treatment of growth disorders in the Gulf Cooperation Council (GCC) countries have been summarized. Evidence-based procedures, relating specifically to height screening for identification of short stature, auxological criteria for patient referral from primary to secondary pediatric care, and general and endocrine investigations and diagnosis have been discussed and outlined. The management issues related to key disorders that are licensed for growth hormone (hGH) therapy, namely GH deficiency, Turner syndrome, short stature related to birth size small for gestational age (SGA), and idiopathic short stature are discussed with recommendations described for best practice. Finally, two key components of short stature management, namely transitional care for the transfer of patients from pediatric to adult endocrinology services and adherence to recommended therapy with hGH, have been addressed with current practice outlines and recommendations presented.

SGA Children in Pediatric Primary Care: What Is the Best Choice, Large or Small? A 10-Year Prospective Longitudinal Study

BACKGROUND

Epidemiologic evidences suggest a strong association between low birth weight and some diseases in adult life ( hypertension, diabetes, cardiovascular diseases).Aim of this study was to evaluate the obesity/overweight prevalence in a population of children born small for gestation age, SGA children 400, 208 males and 192 females compared to a population of children born appropriate for gestational age 6818 AGA children, 3502 males and 3316 females, during childhood. Our intention was also to build the natural history of weight gain during prepubertal age in children born SGA and AGA.

DESIGN AND METHODS

Observational prospective longitudinal study. We followed our patients from January2001 up to December 2010; weight, height and body mass index (BMI) were evaluated in all the SGA and AGA children. BMI z-score range for defining overweight and obesity was, respectively, 1.13 to 1.7 and >1.7 according to CDC growth charts.

RESULTS

In transversal evaluation, we prove that 10-year-old SGA females are twice obese and more overweight compared to equal age AGA females. In longitudinal evaluation, we highlight different observations: SGA children obese at 2 years are still obese at 10 years; the number of obese SGA children increases gradually until the age of 10; AGA children, appear to be less obese than SGA children at 10 years.

CONCLUSION

SGA males and females are more obese at 5 and 10 years compared to the AGA population. Primary care pediatricians, through early detection of the children at risk, can carry out an effective obesity prevention project in SGA children.

Is safety of childhood growth hormone therapy related to dose? Data from a large observational study

OBJECTIVE

Concerns have been raised of increased mortality risk in adulthood in certain patients who received growth hormone treatment during childhood. This study evaluated the safety of growth hormone treatment in childhood in everyday practice.

DESIGN

NordiNet(®) International Outcome Study (IOS) is a noninterventional, observational study evaluating safety and effectiveness of Norditropin(®) (somatropin; Novo Nordisk A/S, Bagsvaerd, Denmark).

METHODS

Long-term safety data (1998-2013) were collected on 13 834 growth hormone treated pediatric patients with short stature. Incidence rates (IRs) of adverse events (AEs) defined as adverse drug reactions (ADRs), serious ADRs (SADRs), and serious AEs (SAEs) were calculated by mortality risk group (low/intermediate/high). The effect of growth hormone dose on IRs and the occurrence of cerebrovascular AEs were investigated by the risk group.

RESULTS

We found that 61.0% of patients were classified as low-risk, 33.9% intermediate-risk, and 5.1% high-risk. Three hundred and two AEs were reported in 261 (1.9%) patients during a mean (s.d.) treatment duration of 3.9 (2.8) years. IRs were significantly higher in the high- vs the low-risk group (high risk vs low risk-ADR: 9.11 vs 3.14; SAE: 13.66 vs 1.85; SADR: 4.97 vs 0.73 events/1000 patient-years of exposure; P < 0.0001 for all). Except for SAEs in the intermediate-risk group (P = 0.0486) in which an inverse relationship was observed, no association between IRs and growth hormone dose was found. No cerebrovascular events were reported.

CONCLUSIONS

We conclude that safety data from NordiNet(®) IOS do not reveal any new safety signals and confirm a favorable overall safety profile in accordance with other pediatric observational studies. No association between growth hormone dose and the incidence of AEs during growth hormone treatment in childhood was found.

Pathological examination of the placenta in small for gestational age (SGA) children with or without postnatal catch-up growth

BACKGROUND/OBJECTIVE

Approximately 10% of small for gestational age (SGA) infants fail to catch up. The relationship between postnatal growth and placental pathology in SGA infants remains unclear. Our aim was to assess the involvement of placental pathology in postnatal growth of SGA infants.

METHODS

We retrospectively evaluated placental pathology and postnatal growth in single-pregnancy infants born after 37 gestational weeks in our institution, with both birth weight and length below -2 standard deviation scores (SDS) of the normal weight and length. "Catch-up" was defined as height reaching -2 SDS before the second birthday. Pathology of the placenta was classified into: abnormality due to maternal factors or fatal factors, villitis of unknown etiology (VUE), other abnormalities and no abnormality.

RESULTS

Of the 33 084 infants, 142 met our criteria and 49 of them had analyzable data. The overall catch-up rate was 84%. Catch-up growth took place in all infants with no placental abnormality and only 57% of infants with abnormality due to fatal factors. There was no significant relationship between catch-up rate and other factors.

CONCLUSION

Placental pathology is associated with postnatal growth in SGA children born at term. Placental abnormality due to fetal factors is related to poor catch-up rate.

Birth parameters and parental height predict growth outcome in children with chronic kidney disease

BACKGROUND

We analyzed the impact of birth parameters and parental height on long-term growth outcome in children with chronic kidney disease (CKD) stage 3-5.

METHODS

Linear growth was prospectively investigated in 509 children, with a mean follow-up of 4.1 years. Growth outcome was categorized in (i) poor growth (PG): height standard deviation score (SDS) during follow-up < -2.0 and/or actual or previous growth hormone (GH) treatment, and (ii) good growth (GG): height SDS ≥ -2.0 and no need for GH. A multivariate binary logistic regression model was constructed for predictors of PG outcome.

RESULTS

PG was observed in 55 % of patients. The rate of pre-term and small for gestational age birth was significantly higher in children with PG compared to GG (43.2 vs. 25.6 % and 36.8 vs. 18.9 %; p < 0.001). Children with PG had significantly lower average values for gestational age, birth weight, length, and head circumference, umbilical cord pH, Apgar scores, and parental height than children with GG. Birth length, umbilical cord pH, and parental height were significant independent predictors of PG outcome (sensitivity 72.8 %, specificity 69.3 %).

CONCLUSIONS

Birth parameters and parental height are independent predictors of growth outcome in children with CKD.