Influence of the exon 3 deletion of GH receptor and IGF-I level at diagnosis on the efficacy and safety of treatment with somatotropin in adults with GH deficiency

PURPOSE

The treatment of adults with GH deficiency (GHD) with human recombinant growth hormone has interindividual variability and several factors influence it. The aims of this study were : 1-to analyze the GH receptor (GHR) genotype in terms of exon 3 deletion GHR (d3-GHR) in adults with GHD; 2-to assess the effects of d3-GHR on initial IGF-I levels; 3-to evaluate whether d3-GHR and/or initial IGF-I levels were associated with adverse effects and/or treatment discontinuation.

METHODS

Forty-four adult patients with GHD were included. Demographic, clinical and biochemical characteristics were retrospectively evaluated at baseline and 6 months, 1 and 3 years after the initiation of treatment. d3-GHR was analyzed in 35 patients.

RESULTS

37.1% of patients were d3-GHR carriers (31.4% heterozygous, 5.7% homozygous). IGF-I at baseline was low in 64% of patients and was not related to d3-GHR status. There was no association between the d3-GHR allele and baseline IGF-I (p = 0.14). Although adverse events were more frequent in the d3-GHR carriers (30.7 vs. 18.2% in fl/fl) and in patients with normal IGF-I levels at diagnosis (43.7 vs. 17.8% in patients with low IGF-I levels), this association was not statistically significant. d3-GHR status was not related to the incidence of adverse events (p = 0.4) or treatment discontinuation (p = 0.47). Baseline IGF-I levels were neither associated with adverse events (p = 0.08) nor treatment discontinuation (p = 0.75).

CONCLUSIONS

The d3-GHR allele was not related to baseline levels of IGF-I. Neither d3-GHR nor baseline IGF-I level was related to adverse events or treatment discontinuation.

Genetic basis of short stature

Growth in humans is a complex process controlled by many genetic and non-genetic factors. It is influenced by endogenous factors like genetics, hormones and metabolism as well as exogenous ones like nutrition, physical activity and psychosocial status. Growth is one of the most sensitive markers of children's health, their nutritional status and genetic background. Besides, deviation from normality may be the first manifestation of an underlying congenital or acquired pathology. Thus, it is important to know the growth process and the disorder that can disturb it. Short stature is defined as a condition in which the height of an individual is more than 2 SD below the corresponding mean height for a given age, sex and population group. This disorder is a major concern for patients and their parents, and represents a diagnostic challenge to the clinician. A correct diagnosis is particularly important in view of the availability of effective, but costly, therapy in a small subset of cases. Cytogenetic and molecular analysis can be of great value in this diagnostic process. Emphasis can be made on the advances of molecular genetics, which have characterized human genes involved in the hypothalamus-pituitary-GH axis such as GH, POU1F1, PROP1, GHRHR, GHR, IGF, IGFR, HESX1, LHX3, LHX4, among others. Our current line of investigation is related to the study of some of these genes and the genotype-phenotype relation with the aim of identifying features that add some more light on the genetic origins of short stature.

Therapeutic optimization of growth hormone deficiency in children and adolescents

More than 40 years after the introduction of growth hormone (GH) treatment, many questions remain unanswered. Clearly, with the availability of rhGH and with current treatment protocols, treatment efficacy has improved. However, it still remains unclear whether current treatment protocols are the best possible. Before GH deficiency was recognized as a chronic disease, children only received treatment until normal adult height had been reached. However, it has recently been shown that not all GH-dependent body structures and functions normalize in parallel with height. Furthermore, in adolescents with GH deficiency, the interruption of GH substitution leads to severe hormone deficiency symptoms in adulthood. In the case of an adolescent who meets the biochemical criteria for GH deficiency in adulthood, but does not show alterations of metabolism, body structure, or emotional state, should GH treatment be started in adolescence, or only if and when the clinical syndrome becomes apparent? This is a difficult question to which there is not yet any clear answer, and we suggest that there is a need for further studies in this area. Furthermore, it will be necessary to re-evaluate the situation of patients who have completed their growth, and definitive conclusions will require controlled studies.

High serum IgA concentrations in patients with diabetes mellitus: agewise distribution and relation to chronic complications

In this study we investigated the agewise distributions of serum IgA concentrations in 1251 type 1 and 2224 type 2 diabetic patients, and the association between serum IgA concentration and diabetic complications (retinopathy, neuropathy, nephropathy, macroangiopathy, and hypertension). The IgA concentrations of all groups of diabetic patients were significantly higher than those of the corresponding subgroups of 943 control subjects, except for type 1 patients >60 years of age. High IgA concentrations were found in 23.1% of the whole diabetic group. The prevalence of high IgA was significantly greater in males than in females among type 1 patients (24.4% vs 18%). In conclusion, an increase in circulating IgA concentrations is a generalized phenomenon among diabetic patients; IgA concentrations above the reference range are more common among male than female diabetics; and diabetic complications are associated with a significant increase in serum IgA concentration.

High serum IgA concentrations in patients with diabetes mellitus: agewise distribution and relation to chronic complications

In this study we investigated the agewise distributions of serum IgA concentrations in 1251 type 1 and 2224 type 2 diabetic patients, and the association between serum IgA concentration and diabetic complications (retinopathy, neuropathy, nephropathy, macroangiopathy, and hypertension). The IgA concentrations of all groups of diabetic patients were significantly higher than those of the corresponding subgroups of 943 control subjects, except for type 1 patients >60 years of age. High IgA concentrations were found in 23.1% of the whole diabetic group. The prevalence of high IgA was significantly greater in males than in females among type 1 patients (24.4% vs 18%). In conclusion, an increase in circulating IgA concentrations is a generalized phenomenon among diabetic patients; IgA concentrations above the reference range are more common among male than female diabetics; and diabetic complications are associated with a significant increase in serum IgA concentration.