Genetic causes of proportionate short stature

Diagnosing and treating anterior pituitary hormone deficiency in pediatric patients

Hypopituitarism, or the failure to secrete hormones produced by the anterior pituitary (adenohypophysis) and/or to release hormones from the posterior pituitary (neurohypophysis), can be congenital or acquired. When more than one pituitary hormone axis is impaired, the condition is known as combined pituitary hormone deficiency (CPHD). The deficiency may be primarily due to a hypothalamic or to a pituitary disorder, or concomitantly both, and has a negative impact on target organ function. This review focuses on the pathophysiology, diagnosis and management of anterior pituitary hormone deficiency in the pediatric age. Congenital hypopituitarism is generally due to genetic disorders and requires early medical attention. Exposure to toxicants or intrauterine infections should also be considered as potential etiologies. The molecular mechanisms underlying the fetal development of the hypothalamus and the pituitary are well characterized, and variants in the genes involved therein may explain the pathophysiology of congenital hypopituitarism: mutations in the genes expressed in the earliest stages are usually associated with syndromic forms whereas variants in genes involved in later stages of pituitary development result in non-syndromic forms with more specific hormone deficiencies. Tumors or lesions of the (peri)sellar region, cranial radiation therapy, traumatic brain injury and, more rarely, other inflammatory or infectious lesions represent the etiologies of acquired hypopituitarism. Hormone replacement is the general strategy, with critical periods of postnatal life requiring specific attention.

Role of genetic investigation in the diagnosis of short stature in a cohort of Italian children

BACKGROUND

Short stature (SS) is defined as height more than 2 standard deviations below the mean for age and sex. Hypothyroidism, celiac disease, growth hormone deficiency, hormonal abnormalities, and genetic conditions are among its causes. A wide range of conditions often due to largely unknown genetic variants can elude conventional diagnostic workup.

AIM

We used next-generation sequencing (NGS) to better understand the etiology of SS in a cohort of Italian children.

PATIENTS AND METHODS

The study sample was 125 children with SS of unknown origin referred to our Institute between 2015 and 2021. All had undergone complete auxological and hormonal investigations to exclude common causes of SS. Genetic analysis was performed using a NGS panel of 104 genes. Clinical data were reviewed to clarify the pathogenicity of the variants detected.

RESULTS

In this cohort, 43 potentially causing variants were identified in 38 children. A syndromic genetic condition was diagnosed in 7: Noonan syndrome in 3, Leri-Weill syndrome in 3, and hypochondroplasia in 1. Moreover, 8 benign variants and other 37 like benign variants were found. In 88 children, 179 variants of uncertain significance (VUS) were identified. No variant was found in 16 children.

CONCLUSION

Genetic analysis is a useful tool in the diagnostic workup of patients with SS, in adapting management and treatment, and in identifying syndromes with mild atypical clinical features. The role of VUS should not be underestimated, particularly when multiple VUS with possible mutual worsening effects are present in the same child.

Sex-based differences in growth-related IGF1 signaling in response to PAPP-A2 deficiency: comparative effects of rhGH, rhIGF1 and rhPAPP-A2 treatments

BACKGROUND

Children with pregnancy-associated plasma protein-A2 (PAPP-A2) mutations resulting in low levels of bioactive insulin-like growth factor-1 (IGF1) and progressive postnatal growth retardation have improved growth velocity and height following recombinant human (rh)IGF1 treatment. The present study aimed to evaluate whether Pappa2 deficiency and pharmacological manipulation of GH/IGF1 system are associated with sex-specific differences in growth-related signaling pathways.

METHODS

Plasma, hypothalamus, pituitary gland and liver of Pappa2ko/ko mice of both sexes, showing reduced skeletal growth, and liver of these mice treated with rhGH, rhIGF1 and rhPAPP-A2 from postnatal day (PND) 5 to PND35 were analyzed.

RESULTS

Reduced body and femur length of Pappa2ko/ko mice was associated with increases in: (1) components of IGF1 ternary complexes (IGF1, IGFBP5/Igfbp5, Igfbp3, Igfals) in plasma, hypothalamus and/or liver; and (2) key signaling regulators (phosphorylated PI3K, AKT, mTOR, GSK3β, ERK1/2 and AMPKα) in hypothalamus, pituitary gland and/or liver, with Pappa2ko/ko females having a more prominent effect. Compared to rhGH and rhIGF1, rhPAPP-A2 specifically induced: (1) increased body and femur length, and reduced plasma total IGF1 and IGFBP5 concentrations in Pappa2ko/ko females; and (2) increased Igf1 and Igf1r levels and decreased Ghr, Igfbp3 and Igfals levels in the liver of Pappa2ko/ko females. These changes were accompanied by lower phospho-STAT5, phospho-AKT and phospho-ERK2 levels and higher phospho-AMPK levels in the liver of Pappa2ko/ko females.

CONCLUSIONS

Sex-specific differences in IGF1 system and signaling pathways are associated with Pappa2 deficiency, pointing to rhPAPP-A2 as a promising drug to alleviate postnatal growth retardation underlying low IGF1 bioavailability in a female-specific manner.

Exercise combined with lysine-inositol vitamin B12 promotes height growth in children with idiopathic short stature

OBJECTIVE

This study was aimed to systematically determine the effect of exercise combined with lysine-inositol vitamin B12 (VB12) therapy on the height of children with idiopathic short stature (ISS).

METHODS

Sixty children with ISS were randomly divided into observation and control groups (N = 30). Each group was given lysine-inositol VB12 oral solution (10 mL bid). Simultaneously, the observation group exercised following the "ISS exercise instruction sheet". The height (H), growth velocity (GV), height standard deviation score (HtSDS) and other indicators were compared after 6 and 12 months of intervention, respectively. After 12 months of intervention, the biochemical indicators of the two groups, together with the correlation between the average days of exercise per week and average minutes of exercise per day, GV and serum growth hormone were analyzed.

RESULTS

After 6 and 12 months of treatment, the GV, serum GHRH, GHBP, GH, IGF-1, and IGFBP-3 levels in the observation group were significantly higher than those in the control group, and HtSDS was significantly lower than that in the control group (P<0.01). After 12 months of treatment, the height of the observation group was significantly higher than that of the control group (P<0.05). There was no significant difference in the biochemical indicators between two groups (P>0.05). Average days of exercise per week and average minutes of exercise per day were positively correlated with GV and GHBP levels. Serum GHRH, GH, IGF-1, and IGFBP-3 levels were negatively correlated. Average minutes of exercise per day were negatively correlated with GV and GHBP levels. Serum GHRH, GH, IGF-1, and IGFBP-3 levels were positively correlated.

CONCLUSION

Regular and moderate stretching exercises combined with lysine-inositol VB12 can effectively promote height growth of children with ISS, which is clinically safe. The mechanism promotes serum GHRH, GHBP, GH, IGF-1, and IGFBP-3 levels.

Beware of missed diagnosis in patients with multiple genetic diseases: a case report

Background

Duchenne muscular dystrophy (DMD) is an X-linked recessive inherited disorder caused by the absence of the Dystrophin protein. Cerebral cavernous malformations (CCMs) are the most common vascular abnormalities in the central nervous system caused by the absence of the products of the CCM genes. Most CCMs cases reported occurring in a sporadic form are often asymptomatic.

Case presentation

We report a rare case of a 7-year-old Chinese boy with a co-existing DMD and sporadic CCMs. We found classic clinical features of DMD and non-specific pathological changes in his brain. We made the definitive diagnosis based on the results of whole-exome sequencing (WES), a repeat from exon 3 to exon 9 of the DMD inherited from his mother, and a de novo heterozygote nonsense mutation C.418G > T of the PDCD10 exon 6.

Conclusion

We should take care to avoid missed diagnoses in patients with multiple genetic disorders.

Primary Dwarfism, Microcephaly, and Chorioretinopathy due to a PLK4 Mutation in Two Siblings

INTRODUCTION

Primary autosomal recessive microcephalies (MCPHs) are characterized by primary dwarfism with MCPH and may present delayed psychomotor development and visual impairment. Biallelic loss of function variants in the PLK4 gene, which encodes the polo-like kinase 4 protein involved in centriole biogenesis, has been recently identified in several patients with MCPH and various ethnic backgrounds.

CASE PRESENTATION

Here, we describe 2 siblings of different sex from Equatorial Guinea harboring a homozygous frameshift mutation in PLK4 (c.1299_1303del, p.Phe433Leufs*6). A Seckel syndrome spectrum phenotype was present in both siblings, with short stature, severe MCPH, reduced brain volume, and distinctive facial features. They also presented severe intellectual disability, lissencephaly/pachygyria, subependymal heterotopia, and ophthalmological impairment. One of them suffered from deafness, and scoliosis was observed in the other.

DISCUSSION/CONCLUSION

Biallelic variants in PLK4 lead to a syndrome where severe short stature, MCPH, and cognitive impairment are constant features. However, ocular, skeletal, and other neurological manifestations can vary upon the same genetic basis.

Exploring the genetic causes of isolated short stature. What has happened to idiopathic short stature?

Statural growth is underpinned by development of the growth plate during the process of endochondral ossification, which is strongly regulated by numerous local factors (intracellular, paracrine and extracellular matrix factors) and systemic factors (nutrition, hormones, proinflammatory cytokines and extracellular fluids). This explains why growth retardation can be associated with numerous pathologies, particularly genetic syndromes, hormonal or inflammatory conditions, or gastrointestinal disorders having a nutritional impact. However, in most cases (80%), no specific aetiology is found after clinical investigation and conventional additional tests have been carried out. In such cases, "idiopathic" short stature is diagnosed, which includes patients presenting with constitutional delay of growth and development and familial short stature, but also patients with very subtle constitutional skeletal dysplasia which are not easily identifiable. In recent years, new methods of genetic investigation (e.g. gene panels, exome or genome sequencing) have made it possible to identify many genetic variants associated with apparently isolated short stature. Indeed, it is still difficult to estimate the proportion of patients presenting with idiopathic short stature for which a molecular diagnosis of monogenic conditions could be made. This estimate varies hugely depending on the thoroughness of the clinical, laboratory and radiological assessments performed prior to molecular analysis, since retrospective analysis of positive cases usually reveals subtle signs of underlying syndromes or rare skeletal disorders. Molecular diagnosis in children is important to be able to offer genetic counselling and to organise patient management. Moreover, improved understanding of the molecular basis of these cases of short stature opens up numerous possibilities for more specific treatments targeting the growth plate. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

Short stature leads to a diagnosis of Jansen-de Vries syndrome in two unrelated Taiwanese girls: A case report and literature review

Short stature and intellectual disability are two of the major components of many dysmorphic syndromes. Jansen-de Vries syndrome (JDVS) is a rare syndromic disorder that was discovered recently using next-generation sequencing. It is characterized by hypotonia, developmental delay, a dysmorphic face, short stature, and high pain threshold and is caused by the variants of the protein phosphatase magnesium-dependent 1D (PPM1D) gene. Here, we report the first two cases of PPM1D mutations in Taiwan; both had de novo variants in exon 6. Both presented with short stature, developmental delay, and dysmorphic faces. In addition to the characteristics listed above, syndactyly was noted in one. Genetic studies should be considered when approaching a patient with growth retardation, intellectual disability, and other major or minor dysmorphisms.

Balanced assessment of growth disorders using clinical, endocrinological, and genetic approaches

Determining the pathogenesis of pediatric growth disorders is often challenging. In many cases, no pathogenesis is identified, and a designation of idiopathic short stature is used. The investigation of short stature requires a combination of clinical, endocrinological, and genetic evaluation. The techniques used are described, with equal importance being given to each of the 3 approaches. Clinical skills are essential to elicit an accurate history, family pedigree, and symptoms of body system dysfunction. Endocrine assessment requires hormonal determination for the diagnosis of hormone deficiency and initiation of successful replacement therapy. Genetic analysis has added a new dimension to the investigation of short stature and now uses next-generation sequencing with a candidate gene approach to confirm probable recognizable monogenic disorders and exome sequencing for complex phenotypes of unknown origin. Using the 3 approaches of clinical, endocrine, and genetic probes with equal status in the hierarchy of investigational variables provides the clinician with the highest chance of identifying the correct causative pathogenetic mechanism in a child presenting with short stature of unknown origin.

Genetic testing in pediatric endocrine pathology

In genetic endocrine diseases, genetic testing is necessary for a precise diagnosis, which will provide a better knowledge of the evolution and prognosis and also indicate the adequate therapy, targeting the precise etiopathogenesis of the disease. Genetic testing in endocrinology is often based on classical cytogenetic techniques, molecular cytogenetic analysis or molecular biology techniques. Genetic testing in disorders of sex development includes the karyotype and SRY gene analysis and depending on the presence of associated clinical signs and on the observations at paraclinical examination, these tests will be followed by chromosomal array techniques and NGS sequencing. In short stature, the decision to perform a genetic test is taken depending on clinical, paraclinical and imaging signs. In case of a short stature associated with a low weight/length for gestational age, genetic testing is proposed to evaluate a Russell-Silver syndrome or if the short stature is associated with other clinical signs (e.g. intellectual disability), chromosomal analysis by microarray is proposed. If the short stature is disproportionate, it is indicated to perform a next generation sequencing (NGS) of a panel of genes involved in skeletal dysplasia. If an endocrine cause for short stature is observed at the hormonal evaluation, it is indicated to test a panel of genes involved in these pathways. In genetic obesity, depending on clinical signs associated to obesity, it will be a more targeted genetic testing. If obesity is associated with intellectual disability or other nonspecific neurological changes, a chromosomal analysis by microarray will be indicated. If monogenic obesity is suspected, NGS testing will be indicated (as genes panel or whole exome or genome analysis). Genetic testing in endocrine diseases brings an etiological diagnosis, but a favorable cost-benefit ratio derives from an adequate indication of these tests, generally proposed in expert centers for rare endocrine diseases.

Milestones of Precision Medicine: An Innovative, Multidisciplinary Overview

Although the concept of precision medicine, in which healthcare is tailored to the molecular and clinical characteristics of each individual, is not new, its implementation in clinical practice has been heterogenous. In some medical specialties, precision medicine has gone from being just a promise to a reality that achieves better patient outcomes. This is a fact if we consider, for example, the great advances made in the genetic diagnosis and subsequent treatment of countless hereditary diseases, such as cystic fibrosis, which have improved the life expectancy of many of the affected children. In the field of oncology, the development of targeted therapies has prolonged the survival of patients with breast, lung, colorectal, melanoma, and hematological malignancies. In other disciplines, clinical milestones are perhaps less well known, but no less important. The current challenge is to expand and generalize the use of technologies that are central to precision medicine, such as massively parallel sequencing, to improve the management (prevention and treatment) of complex conditions such as cardiovascular, kidney, or autoimmune diseases. This process requires investment in specialized expertise, multidisciplinary collaboration, and the nationwide organization of genetic laboratories for diagnosis of specific diseases.

Digital Health for Supporting Precision Medicine in Pediatric Endocrine Disorders: Opportunities for Improved Patient Care

Digitalization of healthcare delivery is rapidly fostering development of precision medicine. Multiple digital technologies, known as telehealth or eHealth tools, are guiding individualized diagnosis and treatment for patients, and can contribute significantly to the objectives of precision medicine. From a basis of "one-size-fits-all" healthcare, precision medicine provides a paradigm shift to deliver a more nuanced and personalized approach. Genomic medicine utilizing new technologies can provide precision analysis of causative mutations, with personalized understanding of mechanisms and effective therapy. Education is fundamental to the telehealth process, with artificial intelligence (AI) enhancing learning for healthcare professionals and empowering patients to contribute to their care. The Gulf Cooperation Council (GCC) region is rapidly implementing telehealth strategies at all levels and a workshop was convened to discuss aspirations of precision medicine in the context of pediatric endocrinology, including diabetes and growth disorders, with this paper based on those discussions. GCC regional investment in AI, bioinformatics and genomic medicine, is rapidly providing healthcare benefits. However, embracing precision medicine is presenting some major new design, installation and skills challenges. Genomic medicine is enabling precision and personalization of diagnosis and therapy of endocrine conditions. Digital education and communication tools in the field of endocrinology include chatbots, interactive robots and augmented reality. Obesity and diabetes are a major challenge in the GCC region and eHealth tools are increasingly being used for management of care. With regard to growth failure, digital technologies for growth hormone (GH) administration are being shown to enhance adherence and response outcomes. While technical innovations become more affordable with increasing adoption, we should be aware of sustainability, design and implementation costs, training of HCPs and prediction of overall healthcare benefits, which are essential for precision medicine to develop and for its objectives to be achieved.

Short stature with low insulin-like growth factor 1 availability due to pregnancy-associated plasma protein A2 deficiency in a Saudi family

In 2016 a new syndrome with postnatal short stature and low IGF1 bioavailability caused by biallelic loss-of-function mutations in the gene encoding the metalloproteinase pregnancy-associated plasma protein A2 (PAPP-A2) was described in two families. Here we report two siblings of a third family from Saudi Arabia with postnatal growth retardation and decreased IGF1 availability due to a new homozygous nonsense mutation (p.Glu886* in exon 7) in PAPPA2. The two affected males showed progressively severe short stature starting around 8 years of age, moderate microcephaly, decreased bone mineral density, and high circulating levels of total IGF1, IGFBP3, and the IGF acid-labile subunit (IGFALS), with decreased free IGF1 concentrations. Interestingly, circulating IGF2 and IGFBP5 were not increased. An increase in growth velocity and height was seen in the prepuberal patient in response to rhIGF1. These patients contribute to the confirmation of the clinical picture associated with PAPP-A2 deficiency and that the PAPPA2 gene should be studied in all patients with short stature with this characteristic phenotype. Hence, pediatric endocrinologists should measure circulating PAPP-A2 levels in the study of short stature as very low or undetectable levels of this protein can help to focus the diagnosis and treatment.

Snow White and the Seven Dwarfs: a fairytale for endocrinologists

'Snow White and the Seven Dwarfs', a fairytale that is widely known across the Western world, was originally written by the Brothers Grimm, and published in 1812 as 'Snow White'. Though each dwarf was first given an individual name in the 1912 Broadway play, in Walt Disney's 1937 film 'Snow White and the Seven Dwarfs', they were renamed, and the dwarfs have become household names. It is well known that myths, fables, and fairytales, though appearing to be merely children's tales about fictional magical beings and places, have, more often than not, originated from real facts. Therefore, the presence of the seven brothers with short stature in the story is, from an endocrinological point of view, highly intriguing, in fact, thrilling. The diversity of the phenotypes among the seven dwarfs is also stimulating, although puzzling. We undertook a differential diagnosis of their common underlying disorder based on the original Disney production's drawings and the unique characteristics of these little gentlemen, while we additionally evaluated several causes of short stature and, focusing on endocrine disorders that could lead to these clinical features among siblings, we have, we believe, been able to reveal the underlying disease depicted in this archetypal tale.

Recombinant IGF-1 Induces Sex-Specific Changes in Bone Composition and Remodeling in Adult Mice with Pappa2 Deficiency

Deficiency of pregnancy-associated plasma protein-A2 (PAPP-A2), an IGF-1 availability regulator, causes postnatal growth failure and dysregulation of bone size and density. The present study aimed to determine the effects of recombinant murine IGF-1 (rmIGF-1) on bone composition and remodeling in constitutive Pappa2 knock-out (ko/ko) mice. To address this challenge, X-ray diffraction (XRD), attenuated total reflection-fourier transform infra-red (ATR-FTIR) spectroscopy and gene expression analysis of members of the IGF-1 system and bone resorption/formation were performed. Pappa2^ko/ko mice (both sexes) had reduced body and bone length. Male Pappa2^ko/ko mice had specific alterations in bone composition (mineral-to-matrix ratio, carbonate substitution and mineral crystallinity), but not in bone remodeling. In contrast, decreases in collagen maturity and increases in Igfbp3, osteopontin (resorption) and osteocalcin (formation) characterized the bone of Pappa2^ko/ko females. A single rmIGF-1 administration (0.3 mg/kg) induced short-term changes in bone composition in Pappa2^ko/ko mice (both sexes). rmIGF-1 treatment in Pappa2^ko/ko females also increased collagen maturity, and Igfbp3, Igfbp5, Col1a1 and osteopontin expression. In summary, acute IGF-1 treatment modifies bone composition and local IGF-1 response to bone remodeling in mice with Pappa2 deficiency. These effects depend on sex and provide important insights into potential IGF-1 therapy for growth failure and bone loss and repair.

Growth failure: 'idiopathic' only after a detailed diagnostic evaluation

The terms 'idiopathic short stature' (ISS) and 'small for gestational age' (SGA) were first used in the 1970s and 1980s. ISS described non-syndromic short children with undefined aetiology who did not have growth hormone (GH) deficiency, chromosomal defects, chronic illness, dysmorphic features or low birth weight. Despite originating in the pre-molecular era, ISS is still used as a diagnostic label today. The term 'SGA' was adopted by paediatric endocrinologists to describe children born with low birth weight and/or length, some of whom may experience lack of catch-up growth and present with short stature. GH treatment was approved by the FDA for short children born SGA in 2001, and by the EMA in 2003, and for the treatment of ISS in the US, but not Europe, in 2003. These approvals strengthened the terms 'SGA' and 'ISS' as clinical entities. While clinical and hormonal diagnostic techniques remain important, it is the emergence of genetic investigations that have led to numerous molecular discoveries in both ISS and SGA subjects. The primary message of this article is that the labels ISS and SGA are not definitive diagnoses. We propose that the three disciplines of clinical evaluation, hormonal investigation and genetic sequencing should have equal status in the hierarchy of short stature assessments and should complement each other to identify the true pathogenesis in poorly growing patients.

Genome-Wide Association Analysis of Growth Curve Parameters in Chinese Simmental Beef Cattle

The objective of the present study was to perform a genome-wide association study (GWAS) for growth curve parameters using nonlinear models that fit original weight-age records. In this study, data from 808 Chinese Simmental beef cattle that were weighed at 0, 6, 12, and 18 months of age were used to fit the growth curve. The Gompertz model showed the highest coefficient of determination (R² = 0.954). The parameters' mature body weight (A), time-scale parameter (b), and maturity rate (K) were treated as phenotypes for single-trait GWAS and multi-trait GWAS. In total, 9, 49, and 7 significant SNPs associated with A, b, and K were identified by single-trait GWAS; 22 significant single nucleotide polymorphisms (SNPs) were identified by multi-trait GWAS. Among them, we observed several candidate genes, including PLIN3, KCNS3, TMCO1, PRKAG3, ANGPTL2, IGF-1, SHISA9, and STK3, which were previously reported to associate with growth and development. Further research for these candidate genes may be useful for exploring the full genetic architecture underlying growth and development traits in livestock.

A novel GLI2 mutation responsible for congenital hypopituitarism and polymalformation syndrome

OBJECTIVE

We report a novel GLI2 frameshift mutation and describe the phenotypic spectrum of mutations within this gene.

PATIENTS AND METHODS

A male with congenital hypopituitarism and polymalformation syndrome was clinically, biochemically and neuroradiologically characterized. Genetic analysis for congenital hypopituitarism was performed using a targeted NGS custom gene panel.

RESULTS

A heterozygous frameshift mutation, NM_005270.4:c.2125del, p.(Leu709Trpfs*15), was identified in GLI2 exon 12. This mutation has not been previously reported and confirms the diagnosis of Culler-Jones syndrome (MIM #615849).

CONCLUSION

GLI2 mutations should be suspected in the presence of congenital hypopitutarism, characteristic facial abnormalities and polydactyly.

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.