Improvement in growth after two years of growth hormone therapy in very young children born small for gestational age and without spontaneous catch-up growth: results of a multicenter, controlled, randomized, open clinical trial

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.

Early Growth Hormone Initiation Leads to Favorable Long-Term Growth Outcomes in Children Born Small for Gestational Age

CONTEXT

Early initiation of growth hormone (GH) therapy is recommended for short children born small for gestational age (SGA); however, real-world data indicate that treatment is often delayed.

OBJECTIVE

To assess the impact of patient age at GH therapy initiation on long-term growth outcomes and safety in short children born SGA.

METHODS

Analysis of pooled data from NordiNet® International Outcome Study (NCT00960128; 469 European clinics) and the ANSWER Program (NCT01009905; 207 US clinics), two large, complementary observational studies. Patients received GH as prescribed by their treating physician. Enrolled patients born SGA were categorized into three groups based on their age at GH treatment initiation: 2-<4 years, 4-<6 years, and ≥6 years. Patient characteristics at birth and GH initiation, auxology, and safety data were evaluated.

RESULTS

The effectiveness analysis (treatment-naïve and prepubertal patients at GH initiation) included 3,318 patients: 10.7% aged 2-<4 years at therapy initiation, 31.6% aged 4-<6 years, and 57.7% aged ≥6 years. Following 8 years of therapy, the mean improvement in height standard deviation score from baseline was significantly greater in the 2-<4 years group vs the 4-<6 years (+2.5 vs +2.2; P = 0.0054) and ≥6 years groups (+2.5 vs +1.7; P < 0.0001). No unexpected safety events were reported.

CONCLUSION

Early initiation of GH therapy in short children born SGA may be an important contributor to height optimization. The data are reassuring regarding the long-term safety of GH therapy in this population.

Achieving Optimal Short- and Long-term Responses to Paediatric Growth Hormone Therapy

It is over sixty years since the first administration of human growth hormone (GH) to children with GH deficiency, and over thirty years since recombinant human GH has been available for treatment of GH deficiency and a wider range of non-GH deficiency disorders. From a diagnostic perspective, genetic analysis, using single gene or Sanger sequencing and more recently next generation or whole exome sequencing, has brought advances in the diagnosis of specific causes of short stature, which has enabled therapy to be targeted more accurately. Genetic discoveries have ranged from defects of pituitary development and GH action to abnormalities in intracellular mechanisms, paracrine regulation and cartilage matrix formation. The strategy of GH therapy using standard doses has evolved to individualised GH dosing, depending on diagnosis and predictors of growth response. Evidence of efficacy of GH in GH deficiency, Turner syndrome and short children born small for gestational age is reviewed. The importance of critical assessment of growth response is discussed, together with the recognition and management of a poor or unsatisfactory growth response and the organisational issues related to prevention, detection and intervention regarding suboptimal adherence to GH therapy.

Genetics of Growth Disorders-Which Patients Require Genetic Testing?

The second 360° European Meeting on Growth Hormone Disorders, held in Barcelona, Spain, in June 2017, included a session entitled Pragmatism vs. Curiosity in Genetic Diagnosis of Growth Disorders, which examined current concepts of genetics and growth in the clinical setting, in terms of both growth failure and overgrowth. For patients with short stature, multiple genes have been identified that result in GH deficiency, which may be isolated or associated with additional pituitary hormone deficiencies, or in growth hormone resistance, primary insulin-like growth factor (IGF) acid-labile subunit deficiency, IGF-I deficiency, IGF-II deficiency, IGF-I resistance, and primary PAPP-A2 deficiency. While genetic causes of short stature were previously thought to primarily be associated with the GH-IGF-I axis, it is now established that multiple genetic anomalies not associated with the GH-IGF-I axis can result in short stature. A number of genetic anomalies have also been shown to be associated with overgrowth, some of which involve the GH-IGF-I axis. In patients with overgrowth in combination with an intellectual disability, two predominant gene families, the epigenetic regulator genes, and PI3K/AKT pathway genes, have now been identified. Specific processes should be followed for decisions on which patients require genetic testing and which genes should be examined for anomalies. The decision to carry out genetic testing should be directed by the clinical process, not merely for research purposes. The intention of genetic testing should be to direct the clinical options for management of the growth disorder.

Clinical response to growth hormone in children with intrauterine growth retardation without catch-up growth in Castilla y León (Spain)

INTRODUCTION AND OBJECTIVES

Growth hormone (rhGH) is used in children with intrauterine growth retardation without catch-up growth. The Advisory Committee of Castilla y León was implemented in 2010 to watch for consistent application of the criteria for using rhGH. The aim is to assess anthropometric and clinical changes in children treated with growth hormone.

PATIENTS AND METHODS

A retrospective, longitudinal study of patients diagnosed with intrauterine growth retardation without catch-up growth in Castilla y León since 2010 who have received treatment for at least 3 years. Changes in anthropometric, clinical, and laboratory parameters were assessed.

RESULTS

Forty-three children with a mean age of 6.06 years (58.14%<5 years) were enrolled and treated with a mean dose of 0.038mg/kg/day. A significant increase was seen in height (-3.05 to -1.58SD). Both weight and BMI (14.51 to 15.80kg/m²) increased throughout the study. Growth rate peaked during the first year of treatment (0.74SD). IGF-1 levels increased throughout the study (99.96 to 392.88ng/mL). There were significant increases in glycosylated hemoglobin levels in the first year, and in basal blood glucose and insulin levels during the second year. The LDL/HDL ratio decreased during the study period (1.70 to 1.50).

CONCLUSION

Treatment with rhGH promotes growth in children with intrauterine growth retardation. Peak effect occurs in the first 12 months of treatment, and is greater when growth hormone is started before the age of 5 years.

Diagnosis and management of postnatal fetal growth restriction

Fetal growth restriction (FGR) can result from multiple causes, such as genetic, epigenetic, environment, hormonal regulation, or vascular troubles and their potential interaction. The physiopathology of FGR is not yet fully elucidated, but the insulin-like growth factor system is known to play a central role. Specific clinical features can lead to the identification of genetic syndromes in some patients. FGR leads to multiple global health concerns, from the perinatal period, with higher morbidity/mortality, through infancy, with neurodevelopmental, growth, and metabolic issues, to the onset of puberty and later in life, with subfertility and elevated risks of cardiovascular and kidney diseases. Adequate follow-up and therapeutics should be offered to these patients. We first review the main molecular etiologies leading to FGR and their specificities. We then highlight the main issues that FGR can raise later in life before concluding with the proposed management of these children.

Born Small for Gestational Age and Poor School Performance - How Small Is Too Small?

AIM

To assess the relationship between severity of small for gestational age (SGA) and the risk of poor school performance, and to investigate whether adult stature modifies this risk.

METHODS

1,088,980 Swedish children born at term between 1973 and 1988 were categorized into severe SGA (less than -3 standard deviations (SD) of expected birth weight), moderate SGA (-2.01 to -3 SD), mild SGA (-1.01 to -2 SD), and appropriate for gestational age (-1 to 0.99 SD). The risk of poor school performance at the time of graduation from compulsory school (grades <10th percentile) was calculated using unconditional logistic regression models and adjusted for socio-economic factors. In a sub-analysis, we stratified boys by adult stature, and adjusted for maternal but not paternal height.

RESULTS

All SGA groups were significantly associated with an increased risk of poor school performance, with adjusted odds ratios and 95% confidence intervals ranging from 1.85 (1.65-2.07) for severe SGA to 1.25 (1.22-1.28) for mild SGA. In the sub-analysis, all birth weight groups were associated with an increased risk of poor school performance among boys with short stature compared to those with non-short stature.

CONCLUSION

Mild SGA is associated with a significantly increased risk of poor school performance, and the risk increases with severity of SGA. Further, this risk diminishes after adequate catch-up growth.

A 2-year multicentre, open-label, randomized, controlled study of growth hormone (Genotropin®) treatment in very young children born small for gestational age: Early Growth and Neurodevelopment (EGN) Study

OBJECTIVE

In Europe, growth hormone (GH) treatment for children born small for gestational age (SGA) can only be initiated after 4 years of age. However, younger age at treatment initiation is a predictor of favourable response. To assess the effect of GH treatment on early growth and cognitive functioning in very young (<30 months), short-stature children born SGA.

DESIGN

A 2-year, randomized controlled, multicentre study (NCT00627523; EGN study), in which patients received either GH treatment or no treatment for 24 months.

PATIENTS

Children aged 19-29 months diagnosed as SGA at birth, and for whom sufficient early growth data were available, were eligible. Patients were randomized (1:1) to GH treatment (Genotropin®, Pfizer Inc.) at a dose of 0·035 mg/kg/day by subcutaneous injection, or no treatment.

MEASUREMENTS

The primary objective was to assess the change from baseline in height standard deviation score (SDS) after 24 months of GH treatment.

RESULTS

Change from baseline in height SDS was significantly greater in the GH treatment vs control group at both month 12 (1·03 vs 0·14) and month 24 (1·63 vs 0·43; both P < 0·001). Growth velocity SDS was significantly higher in the GH treatment vs control group at 12 months (P < 0·001), but not at 24 months. There was no significant difference in mental or psychomotor development indices between the two groups.

CONCLUSIONS

GH treatment for 24 months in very young short-stature children born SGA resulted in a significant increase in height SDS compared with no treatment.

Stunting at 5 Years Among SGA Newborns

OBJECTIVE

To compare risk of stunting at 5 years across etiological subgroups of small for gestational age (SGA) newborns.

METHODS

We analyzed data of a subsample (N = 1100) of the Early Childhood Longitudinal Study-Birth Cohort. We defined SGA as birth weight <10th percentile, then classified subjects into etiological subgroups by each of 8 risk factors (ie, maternal prepregnancy underweight, short stature, smoking during pregnancy, alcohol use during pregnancy, inadequate gestational weight gain [GWG], hypertension, genital herpes infection, and multiple births) or by cooccurrence of 2 often intertwined risk factors (smoking and inadequate GWG). We defined stunting as 5 years height-for-age z score below -2. We fitted logistic regression models to test whether the risk of stunting differed across SGA subgroups, adjusting for confounders.

RESULTS

SGA subgroup with maternal short stature (odds ratio [OR] = 3.88; 95% confidence interval [CI] = 2.16-6.96) or inadequate GWG (OR = 2.18; 95% CI = 1.23-3.84) had higher risk of stunting at 5 years, compared with the SGA subgroup without the corresponding risk factor. SGA newborns with both maternal smoking and inadequate GWG during pregnancy had much higher risk of stunting at 5 years (OR = 3.10; 95% CI = 1.21-7.91), compared with SGA newborns without any of these 2 SGA risk factors.

CONCLUSIONS

Etiological subgroups of SGA differed in risk of stunting at 5 years. SGA newborns of inadequate GWG mothers who smoke and SGA newborns of short mothers were at particularly high risk of stunting.

Effects of Growth Hormone on Bone

PURPOSE

Describe the effects of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) on the skeleton.

FINDINGS

The GH and IGF-1 axis has pleiotropic effects on the skeleton throughout the lifespan by influencing bone formation and resorption. GH deficiency leads to decreased bone turnover, delayed statural growth in children, low bone mass, and increased fracture risk in adults. GH replacement improves adult stature in GH deficient children, increases bone mineral density (BMD) in adults, and helps to optimize peak bone acquisition in patients, during the transition from adolescence to adulthood, who have persistent GH deficiency. Observational studies suggest that GH replacement may mitigate the excessive fracture risk associated with GH deficiency. Acromegaly, a state of GH and IGF-1 excess, is associated with increased bone turnover and decreased BMD in the lumbar spine observed in some studies, particularly in patients with hypogonadism. In addition, patients with acromegaly appear to be at an increased risk of morphometric-vertebral fractures, especially in the presence of active disease or concurrent hypogonadism. GH therapy also has beneficial effects on statural growth in several conditions characterized by GH insensitivity, including chronic renal failure, Turner syndrome, Prader-Willi syndrome, postnatal growth delay in patients with intrauterine growth retardation who do not demonstrate catchup growth, idiopathic short stature, short stature homeobox-containing (SHOX) gene mutations, and Noonan syndrome.

SUMMARY

GH and IGF-1 have important roles in skeletal physiology, and GH has an important therapeutic role in both GH deficiency and insensitivity states.

Three-year growth response to growth hormone treatment in very young children born small for gestational age-data from KIGS

CONTEXT

Children born small for gestational age (SGA) with poor growth during the first years of life may remain short in stature during childhood and as adults.

OBJECTIVE

To evaluate the 3-year growth response to GH treatment in very young short children born SGA, and to test the existing predictions models for growth response developed for older SGA children.

SETTING

KIGS (The Pfizer International Growth Database).

PATIENTS

A total of 620 SGA children (birth length and/or weight below -2 SD score [SDS]) on GH treatment, 156 in the 2- to 4-year-old group (100 boys; median age, 3.3 y), and 464 in the 4- to 6-year-old group (284 boys; median age, 4.9 y).

RESULTS

Median values and 10th-90th percentiles are presented. Both groups presented a significant increase in height velocity during GH treatment. Median height SDS increased from -3.9 (-5.4 to -2.9) at the start to -2.2 (-3.8 to -1.0) at 3 years in the 2- to 4-year-old group (P < .01) and from -3.4 (-4.5 to -2.6) to -2.0 (-3.3 to -0.9) in the 4- to 6-year-old group (P < .01). Median weight SDS increased from -3.8 (-5.9 to -2.4) to -2.1 (-4.1 to -0.5) in the 2- to 4-year-old group (P < .01). Respective values for the 4- to 6-year-old group were -3.1 (-4.8 to -1.8) to -1.6 (-3.1 to -0.1) SDS (P < .01). First- and second-year growth response could be estimated by the SGA model.

CONCLUSION

Very young children born SGA without spontaneous catch-up growth presented a significant improvement in height and weight during the 3 years of GH treatment. Growth response could be estimated by the SGA model.

SGA children: auxological and metabolic outcomes - the role of GH treatment

The definition Small for Gestational Age (SGA) describes those newborns weighing and/or measuring in length <-2 SD than expected for their gestational age. These subjects are at higher risk of short stature, neonatal complications, alterations of glucose, lipid metabolism, body composition, bone metabolism and puberty, neurocognitive vulnerabilities and alterations of the GH-IGF-I axis. With regards to growth, in 85-90% of the cases children born SGA experience a period of catch up growth that allows them to achieve an adult stature within normal range. In a 10-15% of the cases, the catch up growth period does not take place and this entails short stature in adulthood. In the latter group, GH treatment may be considered to achieve adult height in the range of genetical target stature. With reference to glucose and lipid metabolism, young adults born SGA and particularly those with early catch up growth are at higher risk of developing insulin resistance, type 2 diabetes mellitus, arterial hypertension, dyslipidemia, overweight, obesity and metabolic syndrome. Subjects born SGA are in need of a correct diagnostic and eventually therapeutic approach.

Effect of recombinant human growth hormone on changes in height, bone mineral density, and body composition over 1-2 years in children with Hurler or Hunter syndrome

Patients with Hurler or Hunter syndrome typically have moderate to severe growth deficiencies despite therapy with allogeneic hematopoietic stem cell transplantation and/or enzyme replacement therapy. It is unknown whether treatment with recombinant human growth hormone (hGH) can improve growth in these children. The objectives of this study were to determine the effects of hGH on growth, bone mineral density (BMD), and body composition in children with Hurler or Hunter syndrome enrolled in a longitudinal observational study. The difference in annual change in outcomes between hGH treated and untreated subjects was estimated by longitudinal regression models that adjusted for age, Tanner stage, and sex where appropriate. We report on 23 participants who completed at least 2 annual study visits (10 [43%] treated with hGH): Hurler syndrome (n=13) average age of 9.8 ± 3.1 years (range 5.3-13.6 years; 54% female) and Hunter syndrome (n=10) average age of 12.0 ± 2.7 years (range 7.0-17.0 years; 0% female). As a group, children with Hurler or Hunter syndrome treated with hGH had no difference in annual change in height (growth velocity) compared to those untreated with hGH. Growth velocity in hGH treated individuals ranged from -0.4 to 8.1cm/year and from 0.3 to 6.6 cm/year in the untreated individuals. Among children with Hunter syndrome, 100% (N=4) of those treated but only 50% of those untreated with hGH had an annual increase in height standard deviation score (SDS). Of the individuals treated with hGH, those with GHD had a trend towards higher annualized growth velocity compared to those without GHD (6.5 ± 1.9 cm/year vs. 3.5 ± 2.1cm/year; p=.050). Children treated with hGH had greater annual gains in BMD and lean body mass. In conclusion, although as a group we found no significant difference in growth between individuals treated versus not treated with hGH, individual response was highly variable and we are unable to predict who will respond to treatment. Thus, a trial of hGH may be appropriate in children with Hurler or Hunter syndrome, severe short stature, and growth failure. However, efficacy of hGH therapy should be evaluated after 1 year and discontinued if there is no increase in growth velocity or height SDS. Finally, the long-term benefits of changes in body composition with hGH treatment in this population are unknown.

Growth of short children born small for gestational age and their response to growth hormone therapy

Growth hormone [GH] is licensed for use in children born small for gestational age (SGA) who fail to catch-up. We retrospectively compared the response of twenty children born SGA (who satisfied the auxological criteria) to growth hormone (Group I) versus randomly selected age and sex matched controls from a group of SGA children with growth related complaints, not treated with GH (Group II). After 2 years of GH therapy the HAZ increased from -2.8 to -1.6 in Group I, compared 2.2 to -1.7 in group II (P-value < 0.05). The percentage of pubertal children rose from 55% to 65% in cases versus 60% to 75% in the controls (P>0.05). GH resulted in increase in growth velocity Z-score during the first year and (4.3±0.5 in Group-I versus - 0.5±0.6 in Group-II, P<0.05) second year of treatment (1.7±0.4 in cases versus -0.6±0.7 in controls, P<0.05).Thus, GH improves height of short SGA children without accelerating pubertal progression.

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

The term small for gestational age (SGA) refers to infants whose birth weights and/or lengths are at least two standard deviation (SD) units less than the mean for gestational age. This condition affects approximately 3%–10% of newborns. Causes for SGA birth include environmental factors, placental factors such as abnormal uteroplacental blood flow, and inherited genetic mutations. In the past two decades, an enhanced understanding of genetics has identified several potential causes for SGA. These include mutations that affect the growth hormone (GH)/insulin-like growth factor (IGF)-1 axis, including mutations in the IGF-1 gene and acid-labile subunit (ALS) deficiency. In addition, select polymorphisms observed in patients with SGA include those involved in genes associated with obesity, type 2 diabetes, hypertension, ischemic heart disease and deletion of exon 3 growth hormone receptor (d3-GHR) polymorphism. Uniparental disomy (UPD) and imprinting effects may also underlie some of the phenotypes observed in SGA individuals. The variety of genetic mutations associated with SGA births helps explain the diversity of phenotype characteristics, such as impaired motor or mental development, present in individuals with this disorder. Predicting the effectiveness of recombinant human GH (hGH) therapy for each type of mutation remains challenging. Factors affecting response to hGH therapy include the dose and method of hGH administration as well as the age of initiation of hGH therapy. This article reviews the results of these studies and summarizes the success of hGH therapy in treating this difficult and genetically heterogenous disorder.

Early diagnosis and treatment referral of children born small for gestational age without catch-up growth are critical for optimal growth outcomes

Approximately 10% of children born small for their gestational age (SGA) fail to show catch-up growth and may remain short-statured as adults. Despite treatment guidelines for children born SGA that recommend referral for growth hormone (GH) therapy evaluation and initiation by ages 2 to 4 years, the average age of GH treatment initiation is typically much later, at ages 7 to 9 years. Delayed referral for GH treatment is problematic as studies show younger age at GH treatment initiation in children born SGA is an independent predictor for responses such as optimal growth acceleration, normalization of prepubertal height, and most importantly, adult height (AH). This review discusses the importance and associated challenges of early diagnosis of children born SGA who fail to show catch-up growth, contrasts the recommended age of referral for these patients and the average age of GH treatment initiation, and discusses studies showing the significant positive effects of early referral and treatment with GH on AHs in short-statured children born SGA. To optimize the eventual height in short-statured SGA children who fail to manifest catch-up growth, a lowering of the average age of referral for GH therapy evaluation is needed to better align with consensus recommendations for SGA management. The importance of increasing parental and physician awareness that most children born SGA will do well developmentally and will optimally benefit from early initiation of GH treatment when short-statured is addressed, as is the need to shift the age of referral to better align with consensus recommendations.

[Follow-up of the small-for-gestational-age child: clinical guidelines]

INTRODUCTION

In this document the Small for Gestational Age (SGA) Child Working Group of the Spanish Society for Paediatric Endocrinology proposes the guidelines for the management and follow-up of SGA children, highlighting the potential morbidity arising from the SGA condition and its consequences in adulthood.

MATERIAL AND METHODS

There is currently a wide variability in the management of the SGA child between health centres and health professionals. The diagnostic criteria for SGA according to the last international consensus guidelines are defined, which also include preterm SGA patients but excluding those patients in whom low birthweigh is associated with specific syndromes. We also outline the potential abnormalities associated with the SGA condition and recommend specific therapeutic and preventative measures.

CONCLUSIONS

Low birth weight remains a major cause of morbidity in childhood and is associated with an increased risk of health problems later in life. Childhood is a critical window during which some of the risk factors accounting for this sequence are potentially reversible, with healthy lifestyle measures and environmental intervention. Accordingly, these guidelines should be useful not only for Primary Care Paediatricians but also for Neonatologists, Paediatric Endocrinologists, Neuropaediatricians and Pediatric Gastroenterologists, and also for the parents.

Latin American consensus: children born small for gestational age

BACKGROUND

Children born small for gestational age (SGA) experience higher rates of morbidity and mortality than those born appropriate for gestational age. In Latin America, identification and optimal management of children born SGA is a critical issue. Leading experts in pediatric endocrinology throughout Latin America established working groups in order to discuss key challenges regarding the evaluation and management of children born SGA and ultimately develop a consensus statement.

DISCUSSION

SGA is defined as a birth weight and/or birth length greater than 2 standard deviations (SD) below the population reference mean for gestational age. SGA refers to body size and implies length-weight reference data in a geographical population whose ethnicity is known and specific to this group. Ideally, each country/region within Latin America should establish its own standards and make relevant updates. SGA children should be evaluated with standardized measures by trained personnel every 3 months during year 1 and every 6 months during year 2. Those without catch-up growth within the first 6 months of life need further evaluation, as do children whose weight is ≤ -2 SD at age 2 years. Growth hormone treatment can begin in SGA children > 2 years with short stature (< -2.0 SD) and a growth velocity < 25th percentile for their age, and should continue until final height (a growth velocity below 2 cm/year or a bone age of > 14 years for girls and > 16 years for boys) is reached. Blood glucose, thyroid function, HbA1c, and insulin-like growth factor-1 (IGF-1) should be monitored once a year. Monitoring insulin changes from baseline and surrogates of insulin sensitivity is essential. Reduced fetal growth followed by excessive postnatal catch-up in height, and particularly in weight, should be closely monitored. In both sexes, gonadal function should be monitored especially during puberty.

SUMMARY

Children born SGA should be carefully followed by a multidisciplinary group that includes perinatologists, pediatricians, nutritionists, and pediatric endocrinologists since 10% to 15% will continue to have weight and height deficiency through development and may benefit from growth hormone treatment. Standards/guidelines should be developed on a country/region basis throughout Latin America.

Growth and body composition in very young SGA children

Infants with a very low birth weight are at risk of a reduced number of nephrons predisposing to kidney disorder, hypertension, and metabolic syndrome. Approximately 3% of infants are born small for gestational age (SGA), defined as birth weight and/or length at least 2 SD below the mean for gestational age (GA), independently of whether these children are born prematurely or at term. About 10% of these children do not show postnatal catch-up growth and remain of short stature during childhood. Most of these infants are not growth hormone (GH)-deficient, but may have GH resistance. Although GH-resistant, the majority of patients benefit from GH therapy, normalize height during childhood, maintain a normal growth velocity during puberty, and attain a normal adult height. To date, GH has been shown to be safe and no significant adverse effects have been demonstrated. Children with congenital chronic kidney disease (CKD) are born with subnormal birth weight and length and about 25% are born SGA. Shortness and need for GH treatment is highly correlated with weight at birth and gestational age. Primary renal disorders modify the response to GH treatment. Analysis of whether SGA is an additional risk factor for CKD regarding the development of hypertension, metabolic syndrome and cardiovascular complications is required.

Growth patterns and the use of growth hormone in the mucopolysaccharidoses

Short stature is characteristic of patients with mucopolysaccharidosis (MPS) diseases. For children with skeletal dysplasias, such as MPS, it is important to know the natural history of growth. An understanding of the natural growth pattern in each MPS disease provides a measurement to which treatments can be compared, as well as data which can help families and providers make individualized decisions about growth promoting treatments. Multiple advancements have been made in the treatment of MPS with both hematopoietic cell transplantation (HCT) and enzyme replacement therapy (ERT). The long term benefit of these treatments on growth is unknown. This article will review the published data on growth in children with MPS, and describe preliminary data on the use of human growth hormone (hGH) in children with MPS.

Growth hormone and bone

PURPOSE OF REVIEW

Description of recent progress in our understanding of growth hormone (GH) effects on bone.

RECENT FINDINGS

Growth hormone deficiency is associated with low bone mass in children and adults, in addition to its well established impact on growth. Although GH and insulin-like growth factor I have direct skeletal actions, it is also possible that disordered parathyroid hormone secretion or effect may mediate some of the deleterious consequences of GH deficiency on bone. The benefits of GH replacement on bone mineral density have been demonstrated in many studies, but it remains unclear whether these are consistent across patient subgroups. The impact of GH replacement on fracture risk has not been definitively established. The positive effects of GH administration on growth are well established in childhood-onset growth hormone deficiency, as well as in several other pediatric conditions. Data on investigational uses of GH are also presented.

SUMMARY

GH may have a relevant role in bone physiology and several disease states in addition to growth hormone deficiency. Although the salutary effects of GH replacement on bone growth and bone density are well characterized, additional studies are required to examine the impact of GH replacement on fracture risk as well as potential benefits in osteoporosis.

Growth hormone treatment for short stature in children born small for gestational age

Children born small for gestational age (SGA) who do not show catch-up in the first 2 years generally remain short for life. Although the majority of children born SGA are not growth hormone (GH) deficient, GH treatment is known to improve average growth in these children.Early studies using GH in children born SGA demonstrated increased height velocity, but these effects tended to be short-term with effects decreasing when GH treatment stopped. With refined GH regimens, significant effects on height have been shown, with gains of approximately 1 standard deviation score after 2 years. Studies have also shown that long-term continuous GH therapy can significantly increase final height to within the normal range. GH treatment of children born SGA does not appear to unduly affect bone age or pubertal development. Growth prediction models have been used to identify various factors involved in the response to GH therapy with age at start, treatment duration, and GH dose showing strong effects. Genetic factors such as the exon 3 deletion of the GH receptor may contribute to short stature of children born SGA and may also be involved in the responsiveness to GH treatment, but there remain other unknown genetic and/or environmental factors. No unexpected safety concerns have arisen in GH therapy trials. In particular, no long-term adverse effects have been seen for glucose metabolism, and positive effects have been shown for lipid profiles and blood pressure.GH treatment in short children born SGA has shown a beneficial, growth-promoting effect in both the short-and long-term, and has become a recognized indication in both the US and Europe. Further studies on individualized treatment regimens and long-term safety are ongoing.

[Growth hormone therapy for short children born small for gestational age]

Approximately 10% of all children born small for gestational age (SGA) fail to achieve sufficient catch-up growth and remain with short stature throughout childhood and adult life. Abnormalities of the GH/IGF-1 axis are not always identified. Several studies have demonstrated that GH is an effective and well-tolerated therapy and most children will reach a normal adult height. In this review, it can be seen the encouraging results of GH treatment in growth-retarded children born SGA highlighting the benefits of early treatment.

Optimal use of growth hormone therapy for maximizing adult height in children born small for gestational age

Growth retardation is a well-known complication of being born small for gestational age (SGA). Approximately 10% of children born SGA do not experience postnatal catch-up growth and are at risk for short adult height. The use of growth hormone (GH) therapy in these short children appears to increase their adult height, but modalities of GH administration remain controversial. Numerous therapeutic strategies have been developed to optimize the efficacy of GH treatment. Data concerning the influence of age at start of GH treatment, duration of GH treatment, GH dosage and method of GH administration on height gain and adult height are reported in this chapter. Longitudinal studies addressing the safety of GH treatment in SGA children are reassuring, but long-term follow-up remains necessary. Recommendations on the management of SGA children during GH treatment are given.

Recombinant human growth hormone for children born small for gestational age: meta-analysis confirms the consistent dose-effect relationship on catch-up growth

BACKGROUND

The optimal treatment regimen of recombinant human GH (r-hGH) for short children born small for gestational age (SGA) is still under discussion.

METHODS

A meta-analysis was performed of existing clinical trials that investigated the treatment of r-hGH in short children diagnosed SGA or with intrauterine growth retardation to determine the relationship between the daily r-hGH dose (placebo/no treatment; 0.033 mg/kg/day; 0.067 mg/kg/day) and the effect on growth [change in height-SD score (SDS) for chronological age]. A mathematical model describing the dose-response relationship was produced, and growth response (gain in height-SDS) to 2 yr of r-hGH 0.033 mg/kg/day [somatropin (rDNA origin) for injection; Serono] was estimated and compared with the response to other r-hGH formulations.

RESULTS

The relationship between r-hGH dose and 2-yr growth response was described by an equation. The equation yielded a mean difference in height- SDS gain of 0.48 (0.35) between r-hGH 0.033 and 0.067 mg/kg/day in favor of the higher dose. The height-SDS gain after 2 yr of Serono r-hGH formulation, 0.033 mg/kg/day was estimated as 1.2. Comparison of this estimate to the growth response to 2-yr treatment at 0.033 mg/kg/day of other r-hGH formulations (mean difference in height-SDS 0.05, lower limit of the 95% confidence interval=-0.15) confirmed that growth response to Serono r-hGH formulation 0.033 mg/kg/day is an inferred response estimated to be within the range of observed responses to a (non-Serono formulation) r-hGH dose of 0.033 mg/kg/day.

CONCLUSION

There is a clear dose-response relationship for r-hGH in the treatment of short children born SGA and the analysis confirmed that treatment with Serono r-hGH formulation 0.033 mg/kg/day should provide a meaningful therapeutic response.