Influence of Body Mass Index on the Growth Hormone Response to Provocative Testing in Short Children without Growth Hormone Deficiency

Obesity and its related factors are known to suppress the secretion of growth hormone (GH). We aimed to evaluate the influence of body mass index (BMI) on the peak GH response to provocative testing in short children without GH deficiency. We conducted a retrospective review of medical records of 88 children (2-15 yr old) whose height was less than 3 percentile for one's age and sex, with normal results (peak GH level > 10 ng/mL) of GH provocative testing with clonidine and dopamine. Peak stimulated GH level, height, weight, pubertal status and serum IGF-1 level were measured. Univariate analysis showed that the BMI standard deviation score (SDS) correlated negatively with the natural log (ln) of the peak stimulated GH level (ln peak GH). BMI SDS did not correlate significantly with sex, age, pubertal status, or ln IGF-1 level. BMI SDS correlated negatively with ln peak GH level induced by clonidine but not by dopamine. In stepwise multivariate regression analysis, BMI SDS was the only significant predictor of ln peak GH level in the combination of tests and the clonidine test, but not in the dopamine test. In children without GH deficiency, BMI SDS correlates negatively with the peak GH level. BMI SDS should be included in the analysis of the results of GH provocation tests, especially tests with clonidine.

Growth response of Egyptian children with idiopathic short stature during four years of growth hormone therapy.

BACKGROUND: Multiple factors affect the growth response to recombinant human growth hormone (rhGH) in children with idiopathic short stature (ISS). AIM: To evaluate the growth responses of children with ISS treated with rhGH, aiming to identify the predictors of growth response. MATERIALS AND METHODS: We studied 120 cases, 90 males (75%), with a mean age of 13.8±2.7 years and 30 females (25%), with a mean age of 12.3±2.5 years. All patients received rhGH with a standard dose of 20 IU/m2/week. The calculated dose per week was divided into six days and given subcutaneous at night. RESULTS: A significant positive trend was detected in the delta changes of all anthropometric data. For the first year, the growth response was positively correlated to CA and BA delay and negatively correlated to height, weight and IGF-1 SDSs. For the second year, the growth response was correlated positively to first year growth velocity, BA, triceps skin fold thickness SDS and deviation from target height, and negatively correlated to weight, IGFBP3 SDS and target height SDS. For the third year, the growth response was positively correlated to five variables namely target height, 2nd year growth velocity, IGF-1 SDS, weight SDS and triceps skin fold thickness SDS. For the fourth year, growth response was positively correlated to 2nd and 3rd year growth velocity, BA, deviation from target height and weight/ height SDS. CONCLUSION: Our study showed multiplicity of predictors that is responsible for response in ISS children treated with rhGH, and BA was an important predictor.

Uso de GH em pacientes com baixa estatura idiopática: [revisão] / GH treatment in patients with idiopathic short stature: [review]

Pacientes com baixa estatura idiopática podem ser tratados com GH. Os critérios clínicos e laboratoriais utilizados na decisão do uso do GH, bem como no reconhecimento da responsividade dos indivíduos ao tratamento, são discutidos. Não apenas os resultados antropométricos, mas também os aspectos éticos e psicossociais devem ser considerados na avaliação dos custos/benefícios envolvidos no tratamento com GH em pacientes com baixa estatura idiopática.

Growth hormone has been used in the treatment of patients with idiopathic short stature. Clinical and laboratorial criteria are discussed, taking into consideration the indication of GH and the evaluation of its efficacy and individual responsiveness. Anthropometric, psychosocial, ethical, and also cost/benefit aspects must be considered before GH prescription in idiopathic short stature patients.

O hormônio de crescimento na síndrome de Turner: dados e reflexões: [revisão] / Growth hormone treatment inTurner syndrome: data and reflections: [review]

A baixa estatura é a principal característica na síndrome de Turner (ST). O agravo estatural na ST é precoce e torna-se mais evidente na puberdade. A haploinsuficiência do gene SHOX tem sido implicada como principal fator na definição da estatura de mulheres, no entanto, ainda que a maioria das pacientes não tenha deficiência do hormônio de crescimento, a terapia com GHr melhora a altura final. Recentemente, tem-se chamado a atenção para a associação entre GH e câncer. O risco de câncer nessas pacientes está associado à presença de fragmentos do cromossomo Y que pode levar ao desenvolvimento de gonadoblastoma. Dessa forma, a administração de GHr na ST deve ser feita com cautela. A investigação de seqüências do cromossomo Y deve ser realizada, bem como a gonadectomia profilática nos casos positivos, conferindo maior segurança ao tratamento.

Short stature is the major characteristic of Turner syndrome. The statural appeal is premature and become evident in the puberty. Haploinsuficiency of SHOX gene has been related as main factor on final height of these patients. Despite the majority of the patients are not growth hormone deficient, the GHr therapy improves the final height. Recently, a great number of publications have described the association between GH and cancer. The cancer risk, in these patients, is mainly associated with the presence of Y chromosome sequences that can lead to the gonadoblastoma development. In conclusion, the GHr therapy in ST patients deserves caution. The investigation of Y chromosome sequences should be performed as well as the prophylactic gonadectomy in the positive cases conferring confidence to the treatment.

Baixa estatura por haploinsuficiência do gene SHOX: do diagnóstico ao tratamento / Short stature caused by SHOX gene haploinsufficiency: from diagnosis to treatment

Estudos realizados em pacientes portadores de deleções parciais dos cromossomos sexuais permitiram a caracterização do SHOX, gene localizado na região pseudoautossômica no braço curto dos cromossomos sexuais, fundamental na determinação da altura normal. A perda de uma cópia deste gene na síndrome de Turner (ST) explica dois terços da baixa estatura observada nesta síndrome. A haploinsuficiência do SHOX é detectada em 77 por cento dos pacientes com discondrosteose de Leri-Weill, uma forma comum de displasia esquelética de herança autossômica dominante e em 3 por cento das crianças com baixa estatura idiopática (BEI), tornando os defeitos neste gene a principal causa monogênica de baixa estatura. A medida da altura sentada em relação à altura total (Z da AS/AT para idade e sexo) é uma forma simples de identificar a desproporção corpórea e, associada ao exame cuidadoso do paciente e de outros membros da família, auxilia na seleção de pacientes para o estudo molecular do SHOX. O uso de hormônio de crescimento (GH) está bem estabelecido na ST e em razão da causa comum da baixa estatura com o de crianças com defeitos isolados do SHOX o tratamento destes pacientes com GH é também proposto. Neste artigo será revisado os aspectos clínicos, moleculares e terapêuticos da haploinsuficiência do SHOX.

Studies involving patients with short stature and partial deletion of sex chromosomes identified SHOX gene in the pseudoautosomal region of the X and Y chromosomes. SHOX haploinsufficiency is an important cause of short stature in a diversity of clinical conditions. It explains 2/3 of short stature observed in Turner syndrome (TS) patients. Heterozygous mutations in SHOX are observed in 77 percent of patients with Leri-Weill dyschondrosteosis, a common dominant inherited skeletal dysplasia and in 3 percent of children with idiopathic short stature, indicating that SHOX defects are the most frequent monogenetic cause of short stature. The sitting height/height ratio (SH/H) standard deviation score is a simple way to assess body proportions and together with a careful exam of other family members, effectively selected a group of patients that presented a high frequency of SHOX mutations. Growth hormone treatment of short stature due to TS is well established and considering the common etiology of short stature in patients with isolated defects of SHOX gene, this treatment is also proposed for these patients. Here, we review clinical, molecular and therapeutic aspects of SHOX haploinsufficiency.

Tratamento com hormônio de crescimento em crianças com doenças crônicas: [revisão] / Growth hormone therapy for children with chronic diseases: [review]

Crianças com doenças crônicas freqüentemente apresentam crescimento inadequado e baixa estatura. A falência do crescimento é multifatorial. Nas doenças inflamatórias, como na artrite juvenil idiopática e nas doenças inflamatórias intestinais, o crescimento é comprometido também pelo processo inflamatório. Muitas vezes, o tratamento da doença de base compromete o crescimento, especialmente quando é necessário glicocorticóides. Em algumas situações é possível comprovar a deficiência associada de hormônio de crescimento (GH, do inglês growth hormone). Em outras, os exames sugerem certo grau de insensibilidade ao GH. O tratamento destes pacientes com GH tem se mostrado útil e seguro com melhora do crescimento e da qualidade de vida. Nesta revisão, são apresentados resultados do tratamento com GH em pacientes com baixa estatura decorrente de doenças crônicas, algumas indicações já bem definidas e outras ainda em investigação.

Growth disorders are commonly observed in children suffering from chronic diseases. The pathogenesis of growth failure is multifactorial. In chronic inflammatory diseases such as juvenile idiopathic arthritis and inflammatory bowel disease, growth is also affected by pro-inflammatory cytokines. Patients with chronic diseases might also become growth hormone (GH) deficient. However, normal or increased GH secretion with reduced plasma concentrations of insulin-like growth factor-I indicate a degree of GH insensitivity in some patients. Growth damage can increase with specific treatments, especially if glucocorticoids are used. GH therapy has been used to reduce the consequences of the disease and long-term steroid therapy in these patients. In this review, it is reported the encouraging results of GH treatment in growth-retarded children with chronic diseases, both in well defined indications as well in situations still under investigation.

A rational approach to short stature: focus on use and abuse of growth hormone.

The abundant supply of recombinant growth hormone has raised interesting possibilities of several new applications. While supplementation of the missing hormone in patients with growth hormone deficiency is still the undisputed primary indication for its use, there is now convincing evidence of its usefulness in the therapy of short stature due to Turner syndrome and pre-transplant chronic renal failure in childhood. Numerous studies on patients with other causes of short stature have failed to show any significant benefit in final adult height. Social pressures notwithstanding, it is still premature to advocate the use of this expensive therapy for indications other than the three stated above especially since our understanding of potential long-term complications from such treatment is far from complete.

Growth hormone therapy in children with short stature: is bigger better or achievable?

The introduction of recombinant DNA-synthesized human growth hormone in the mid-1980s, and its attendant unlimited supply, have led to wider application of growth hormone therapy in children. Over the past decade, the efficacy of growth hormone treatment in patients with Turner syndrome and chronic renal insufficiency, two conditions in which growth hormone secretion is normal, in improving growth velocity and final height, has also led to the consideration of growth hormone therapy in children with idiopathic short stature. Although thousands of patients with idiopathic short stature are currently being treated with growth hormone, the limited overall results available at this time do not show a significant improvement in final adult height despite an improvement in short-term growth velocity. Potential reasons for this outcome include 1) skeletal age advancing more rapidly than height age, 2) heterogeneity of the patient population comprising idiopathic short stature, 3) inherent inaccuracies of methodological tools, such as measurement of predicted adult height, and 4) a subset of children with idiopathic short stature who may, in fact, have partial growth hormone insensitivity. From a psychological perspective, the consensus of investigations in non-clinic-referred populations of psychosocial function in children with short stature do not indicate a disadvantage compared with children of normal height when socio-economic status is taken into consideration. These results, in conjunction with the minimal gains reported in behavioural measurements in idiopathic short children treated with growth hormone, question the traditional rationale that augmentation of growth velocity results in improvement in psychosocial well-being.