New Horizons in Short Children Born Small for Gestational Age

Invited Review-Children With Idiopathic Short Stature: An Expanding Role for Genetic Investigation in Their Medical Evaluation

Short stature in children is a common reason for referral to a pediatric endocrinologist. Many genetic, nutritional, psychological, illness-related, and hormonal causes must be excluded before labeling as idiopathic. Idiopathic short stature is not a diagnosis, but rather describes a large, heterogeneous group of children, who are short and often slowly growing. As new testing paradigms become available, the pool of patients labeled as idiopathic will shrink, although most will have a polygenic cause. Given that many of the new diagnoses are involved in growth plate biology, physical examination should assess for subtle dysmorphology or disproportion of the skeleton that may indicate a heterozygous mutation that in its homozygous state would be apparent. When laboratory evaluations are negative, one may consider genetic testing, such as targeted gene or gene panel, comparative genomic hybridization, or whole exome or whole genome sequencing (respectively). With a known genetic diagnosis, targeted therapy may be possible rather than recombinant human growth hormone, where response is generally poorer than that for children with growth hormone deficiency, because the variety of diagnoses may have varying growth hormone sensitivity. A firm diagnosis has heuristic value: to truncate further diagnostic evaluation, alert the clinician to other possible comorbidities, inform the family for genetic counseling, and direct appropriate targeted therapy, if available.

Relationship of Glucagon-like Peptide 1 and Peptide YY with Catch-up Growth in Children Born Small for Gestational Age

Objective

Children born small for gestational age (SGA) are at a greater risk of developing insulin resistance, type 2 diabetes, and cardiovascular disease in adulthood. Gastrointestinal peptides, some secreted by intestinal L cells, regulate glucose and lipid metabolism and act on the hypothalamus to regulate energy homeostasis. The aim of this study was to explore whether gastrointestinal peptides are involved in metabolic disorders in SGA, which remains unclear.

Methods

The secretion of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) were investigated in prepubertal children born SGA, the differences between catch-up growth and persistent short stature were compared, and correlation with glucose and lipid metabolism was analyzed. GLP-1, PYY, insulin-like growth factor 1, glucose, insulin, and lipid concentrations were analyzed in prepubertal children aged 4-10 years, stratified into three groups: short-SGA (SGA-s), catch-up growth SGA, and normal growth appropriate for gestational age (AGA).

Results

Fasting GLP-1 and PYY concentrations were significantly lower in the SGA group than in the AGA group (p<0.05), and the GLP-1 level in infants born SGA with catch-up growth was lower than that in the SGA-s group (p<0.05). In the SGA population, GLP-1 showed a weak negative correlation with catch-up growth (r=-0.326) and positive correlation with fasting insulin (r=0.331).

Conclusion

Lower GLP-1 concentrations may be associated with abnormal glucose metabolism in prepubertal children born SGA with catch-up growth. This is indirect evidence that impaired intestinal L cell function may be involved in the development of metabolic complications in SGA children.

A comprehensive assessment of redox balance in small for gestational age newborns and their mothers

OBJECTIVE

The objective of this study was to assess oxidative stress in small for gestational age (SGA) newborns and their mothers by evaluating intra- and extracellular thiol homeostasis and the quantification of major oxidants and antioxidants.

METHODS

A total of 75 mothers and their 75 newborns (43 SGA) were enrolled in this study. Thiol-disulfide homeostasis, serum myeloperoxidase, catalase, total oxidant, and antioxidant status were analyzed. Additionally, erythrocytic glutathione (GSH) homeostasis was measured.

RESULTS

Although native and total thiol levels were decreased, disulfide levels were increased in SGA groups. Additionally, myeloperoxidase activity and total oxidant status levels were significantly elevated whereas total antioxidant status levels and enzymatic antioxidant systems were diminished in SGA groups. Similarly, intra-erythrocytic GSH homeostasis was shifted in favor of oxidants in SGA groups.

CONCLUSION

Our results demonstrate that insufficient antioxidant systems in mothers and a robust source of oxidative stress in SGA might contribute to the pathophysiology of SGA births.

Genetic evaluation using next-generation sequencing of children with short stature: a single tertiary-center experience

PURPOSE

We used next-generation sequencing (NGS) to investigate the genetic causes of suspected genetic short stature in 37 patients, and we describe their phenotypes and various genetic spectra.

METHODS

We reviewed the medical records of 50 patients who underwent genetic testing using NGS for suspected genetic short stature from June 2019 to December 2022. Patients with short stature caused by nongenetic factors or common chromosomal abnormalities were excluded. Thirty-seven patients from 35 families were enrolled in this study. We administered one of three genetic tests (2 targeted panel tests or whole exome sequencing) to patients according to their phenotypes.

RESULTS

Clinical and molecular diagnoses were confirmed in 15 of the 37 patients, for an overall diagnostic yield of 40.5%. Fifteen pathogenic/likely pathogenic variants were identified in 13 genes (ACAN, ANKRD11, ARID1B, CEP152, COL10A1, COL1A2, EXT1, FGFR3, NIPBL, NRAS, PTPN11, SHOX, SLC16A2). The diagnostic rate was highest in patients who were small for their gestational age (7 of 11, 63.6%).

CONCLUSION

Genetic evaluation using NGS can be helpful in patients with suspected genetic short stature who have clinical and genetic heterogeneity. Further studies are needed to develop patient selection algorithms and panels containing growth-related genes.

Endocrine and metabolic disorders in adolescent and adult patients born small for gestational age

Children born small for gestational age (SGA), defined by a birth weight and/or length standard deviation score (SDS) of < -2 based on an appropriate reference population, represent a diverse group due to multiple underlying causes of reduced growth. This classification results in a heterogeneous patient cohort. SGA children are prone to endocrinological and metabolic issues not only in childhood but also extending into adolescence and adulthood. This population faces elevated health risks, including persistent short stature, premature adrenarche, pubertal development alterations, neurocognitive problems, and metabolic syndrome. Insulin resistance emerges as a pivotal factor c nht6j7ikontributing to these metabolic complications, prominently featuring obesity, insulin resistance, hypertension, and an increased risk of type 2 diabetes mellitus in adulthood. These medium- to long-term complications significantly impact their quality of life. Growth hormone (GH) therapy for short children born SGA facilitates height normalization throughout childhood, adolescence, and into adulthood. Catch-up growth, however, correlates with heightened risks of obesity, insulin resistance, and metabolic syndrome. Conversely, those without catch-up growth tend to exhibit pronounced short stature and cognitive dysfunction. Given these determinants, comprehensive management and clinical monitoring of SGA children should commence in the neonatal period and extend into adulthood. Recognizing and addressing these challenges early in life can mitigate the long-term impact on health and well-being, emphasizing the importance of a lifelong approach to their care.

Association between infant breastfeeding practices and timing of peak height velocity: A nationwide longitudinal survey in Japan

BACKGROUND

Several studies have discovered an association between infant feeding practices and puberty timing; however, most have involved female cohorts. We investigated the association between infant feeding practices and the timing of peak height velocity in boys and girls.

METHODS

Data on infant feeding methods and anthropometric measurements were collected from a nationwide Japanese birth cohort study. The age at peak height velocity (APV, years) was estimated and compared. Subsequently, the effects of breastfeeding duration were analyzed.

RESULTS

Of the 13,074 eligible participants, 650, 9455, and 2969 were formula-, mixed-, and exclusively breastfed, respectively. Among girls, the mean APV was significantly later in the mixed-fed (standardized regression coefficient (β): 0.094, 95% confidence interval (CI): 0.004-0.180) and exclusively breastfed (β: 0.150, 95% CI: 0.056-0.250) groups than in the formula-fed group. Among boys, the mean APV was not significantly different among the three groups; however, a sensitivity analysis that excluded preterm birth revealed more significantly delayed APV in the breastfed-only group compared to the formula-fed group. Furthermore, a multiple linear regression model revealed that a longer breastfeeding period was associated with later APV.

CONCLUSIONS

Infant breastfeeding practices can affect the timing of peak height velocity in both boys and girls.

IMPACT

Several studies have discovered an association between infant feeding practices and puberty timing; however, most have involved female cohorts. Age at peak height velocity, derived from longitudinal height measurements, is a useful marker of secondary sexual maturity milestones in boys and girls. A Japanese birth cohort study revealed that breastfed children had a later age at peak height velocity than their formula-fed counterparts; this was more prominent among girls than boys. Furthermore, a duration-effect relationship was observed, where longer breastfeeding duration was associated with a later age at peak height velocity.

Growth hormone treatment in pediatrics: What can we improve?

OBJECTIVES

To analyze the age at which treatment with growth hormone (GH) is started in the different indications approved in our country, as well as to assess the response to it and detect points of improvement.

MATERIAL AND METHODS

A descriptive, observational and retrospective study of pediatric patients receiving GH treatment in December 2020 and monitored in the pediatric Endocrinology Unit of a tertiary care hospital.

RESULTS

A total of 111 patients (52 females) were included in the study. The mean age at the start of treatment was 6.6 years old, being delayed in all diagnostic groups with respect to what is approved for each indication. The indication for which they most frequently received treatment was GH deficiency (n = 60, 54%). In this diagnostic group, there is a predominance of males (39 boys vs 21 girls, and a significantly greater increase in height z score (greater height SDS) is observed in those with early start of treatment compared to those who start late (greaterheight SDS 0.93 vs 0.6; P < .05). All diagnostic groups presented a greater height SDS and height velocity. No adverse effects were observed in any patient.

CONCLUSION

GH treatment is effective and safe for the approved indications. The age of initiation of treatment is a point to improve in all indications, especially in SGA patients. For this, good coordination between primary care pediatricians and pediatric endocrinologists is essential, as well as specific training to identify early signs of different pathologies.

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.

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.

Automated growth monitoring app (GROWIN): a mobile Health (mHealth) tool to improve the diagnosis and early management of growth and nutritional disorders in childhood

OBJECTIVE

To assess the functionality and feasibility of the GROWIN app for promoting early detection of growth disorders in childhood, supporting early interventions, and improving children's lifestyle by analyzing data collected over 3 years (2018-2020).

METHODS

We retrospectively assessed the growth parameters (height, weight, body mass index [BMI], abdominal circumference) entered by users (caregivers/parents) in the GROWIN app. We also analyzed the potential health problems detected and the messages/recommendations the app showed. Finally, we assessed the possible impact/benefit of the app on the growth of the children.

RESULTS

A total of 21 633 users (Spanish [65%], Latin American [30%], and others [5%]) entered 10.5 ± 8.3 measurements (0-15 y old). 1200 recommendations were for low height and 550 for low weight. 1250 improved their measurements. A specialist review was recommended in 500 patients due to low height. 2567 nutrition tests were run. All children with obesity (n = 855, BMI: 27.8 kg/m2 [2.25 SD]) completed the initial test with a follow-up of ≥1 year. Initial results (score: 8.1) showed poor eating habits (fast food, commercially baked goods, candy, etc.), with >90% not having breakfast. After 3-6 months, BMI decreased ≥1 point, and test scores increased ≥2 points. This benefit was maintained beyond 1 year and was correlated with an improvement in BMI (r = -.65, P = .01).

DISCUSSION/CONCLUSIONS

The GROWIN app represents an innovative automated solution for families to monitor growth. It allows the early detection of abnormal growth indicators during childhood and adolescence, promoting early interventions. Additionally, in children with obesity, an improvement in healthy nutritional habits and a decrease in BMI were observed.

First year metabolic and hormonal behaviour define two different populations of SGA newborn for weight or height

Context

Small for gestational age (SGA) children have a particular metabolic and hormonal pattern at birth that change rapidly.

Objective

To evaluate the linear and weight growth in the first year of life in SGA children.

Design

Prospective, monocentric cohort study.

Setting

Real-world data collected from April 2012 to January 2016.

Patients

SGA newborns uniformly defined by either growth or length lower than -2 standard deviation for gestational age.

Interventions

All children were evaluated for one year after birth, at three days of life, then three, six and 12 months after birth.

Main outcome measures

Anthropometric parameters and biochemical variables, such as blood glucose, insulin, leptin, insulin-like growth factor (IGF)-1, IGF binding protein (IGFBP)3, and HOMA index.

Results

One hundred and thirty-three SGA children were enrolled. Length significantly improved one month after birth, whereas weight significantly increased only three months after birth. Biochemical variables increased during the first year of life, showing a prediction by IGFBP-3 and HOMA-index. Then, the casuistry was divided considering either weight, length or both, showing a different incidence. The biochemical variables changes recorded in the first step were maintained considering SGA children for weight or length, whereas they disappeared when weight and length were considered together.

Conclusions

Our study shows a specific catch-up growth for weight and length in SGA children. Moreover, we highlight that weight and length should be considered as independent parameters in SGA children, defining two different metabolic-hormonal populations with different conceivable predictive role in early catch-up growth and in later growth and metabolic status.

Pubertal timing in children with Silver Russell syndrome compared to those born small for gestational age

CONTEXT

Data on pubertal timing in Silver Russell syndrome (SRS) are limited.

DESIGN AND METHODS

Retrospective observational study including twenty-three SRS patients [11p15 loss of methylation, (11p15 LOM, n=10) and maternal uniparental disomy of chromosome 7 (mUPD7, n=13)] and 21 small for gestational age (SGA). Clinical (thelarche in females; testis volume ≥ 4 ml in males; pubarche), BMI SD trend from the age of 5 to 9 years to the time of puberty, biochemical parameters of puberty onset [Luteinizing hormone (LH), 17-β-estradiol, testosterone], and bone age progression were evaluated.

RESULTS

Pubertal onset and pubarche occurred significantly earlier in children with SRS than in SGA (p 0.03 and p 0.001, respectively) and clinical signs of puberty onset occurred earlier in mUPD7 than in 11p15LOM group (p 0.003). Five SRS children experienced central precocious puberty and LH, 17-β-estradiol, testosterone were detected earlier in SRS than in SGA (p 0.01; p 0.0001). Bone age delay in SRS children was followed by rapid advancement; the delta between bone age and chronological age in SRS group became significantly higher than in SGA group at the age of 9-11 years (p 0.007). 11p15LOM patients were underweight at the age of 5 years and showed a progressive normalization of BMI that was significantly higher than in mUPD7 (p 0.04) and SGA groups (p 0.03) at puberty onset.

CONCLUSION

Timing of puberty is affected in SRS and occurred earlier in mUPD7 compared to 11p15LOM. The impact of early puberty on adult height and metabolic status deserves long-term evaluation.

Should Skeletal Maturation Be Manipulated for Extra Height Gain?

Skeletal maturation can be delayed by reducing the exposure to estrogens, either by halting pubertal development through administering a GnRH analogue (GnRHa), or by blocking the conversion of androgens to estrogens through an aromatase inhibitor (AI). These agents have been investigated in children with growth disorders (off-label), either alone or in combination with recombinant human growth hormone (rhGH). GnRHa is effective in attaining a normal adult height (AH) in the treatment of children with central precocious puberty, but its effect in short children with normal timing of puberty is equivocal. If rhGH-treated children with growth hormone deficiency or those who were born small-for-gestational age are still short at pubertal onset, co-treatment with a GnRHa for 2-3 years increases AH. A similar effect was seen by adding rhGH to GnRHa treatment of children with central precocious puberty with a poor AH prediction and by adding rhGH plus GnRHa to children with congenital adrenal hyperplasia with a poor predicted adult height on conventional treatment with gluco- and mineralocorticoids. In girls with idiopathic short stature and relatively early puberty, rhGH plus GnRHa increases AH. Administration of letrozole to boys with constitutional delay of growth puberty may increase AH, and rhGH plus anastrozole may increase AH in boys with growth hormone deficiency or idiopathic short stature, but the lack of data on attained AH and potential selective loss-of-follow-up in several studies precludes firm conclusions. GnRHas appear to have a good overall safety profile, while for aromatase inhibitors conflicting data have been reported.