[Show abstract][Hide abstract] ABSTRACT: GH and its principal mediator IGF-I have important effects on metabolic and cardiovascular (CV) status. While acquired GH deficiency (GHD) is often associated to increased CV risk, the consequences of congenital GHD are not known. We have described a large group of patients with isolated GHD (IGHD) due to a homozygous mutation (c.57+1G>A) in the GH releasing hormone receptor gene, and shown that adult GH-naïve individuals have no evidence of clinically evident premature atherosclerosis. To test weather subclinical atherosclerosis is anticipated in untreated IGHD, we ruled a cross-sectional study of 25 IGHD and27 adult controls matched for age and gender. A comprehensive clinical and biochemical panel and coronary artery calcium scores were evaluated by multi-detector tomography. Height, weight, IGF-I, homeostasis model assessment of insulin resistance, creatinine and creatininekinase were lower in IGHD group. Median and interquartile range of calcium scores distribution was similar in the two groups: IGHD 0(0) and control 0 (4.9). The vast majority of the calcium scores [20 of 25 IGHD (80%) and 18 of 27 controls (66.6%)] were equal to zero (difference not significant). There was no difference in the calcium scores classification. None of IGHD subjects had minimal calcification, which were present in 4 controls. Three IGHD and four controls had mild calcification. There were two IGHD individuals with moderate calcification and one control with severe calcification. Our study provides evidence that subjects with congenital isolated lifetime and untreated severe IGHD do not have accelerated subclinical coronary atherosclerosis.
Preview · Article · Jan 2016 · Endocrine Connections
[Show abstract][Hide abstract] ABSTRACT: Growth hormone (GH)-releasing hormone (GHRH) is the most important stimulus for GH secretion by the pituitary gland. Subjects homozygous for GHRH receptor (GHRHR) gene (GHRHR) inactivating mutations have severe GH deficiency, resulting in severe short stature if not treated. We previously reported that young adults heterozygous for the c.57+1G>A null GHRHR mutation (MUT/N) have reduced weight and body mass index (BMI) but normal stature. Here we have studied whether older MUT/N have an additional phenotype. In a cross-sectional study, we measured height, weight and blood pressure, and calculated BMI in two groups (young, 20-40 years of age) and old (60-80 years) of individuals heterozygous for the same GHRHR mutation, and compared with a large number of individuals of normal genotype residing in the same geographical area. Standard deviation score (SDS) of weight was lower, and BMI had a trend toward reduction in young heterozygous compared with young normals, without significant difference in stature. Conversely, SDS of height was lower in older heterozygous individuals than in controls, corresponding to a reduction of 4.2 cm. These data show a reduced stature in older subjects heterozygous for the c.57+1G>A GHRHR mutation, indicating different effects of heterozygosis through lifespan.Journal of Human Genetics advance online publication, 12 March 2015; doi:10.1038/jhg.2015.25.
No preview · Article · Mar 2015 · Journal of Human Genetics
[Show abstract][Hide abstract] ABSTRACT: Context: Non-alcoholic fatty liver disease (NAFLD) is known to be associated with insulin resistance, atherosclerosis, and low serum IGF-I levels. We have described a large cohort of patients with isolated GH deficiency (IGHD) due to the c.57+1G→A mutation in the GHRH receptor gene. These subjects have increased insulin sensitivity (IS), delayed atherosclerosis, and normal longevity. We hypothesized that despite visceral obesity NAFLD would be absent or mild due to the increased IS. Objective: To assess the prevalence and severity of NAFLD in adult subjects with lifetime, congenital, untreated IGHD. Methods: We studied 22 IGHD adults and 25 controls (CO) matched for age and gender. NAFLD was assessed by a comprehensive liver function panel, and ultrasonographic pattern (HP) coded as 0=absent; 1=mild; 2=moderate; and 3=severe. Results: Compared to CO, IGHD individual had lower serum IGF-I (p<0.0001), higher total cholesterol (p=0.027), lower prothrombin time (p=0.017), similar activated partial thromboplastin time and fibrinogen values. ALT values were similar in the two groups, but AST was higher in IGHD (p=0.013). However, more IGHD subjects (7/22) than CO (3/23) had ALT above the upper limit of normal (p=0.044). The prevalence of NAFLD was higher in IGHD than CO (61% vs. 29%, p=0.032), and the HP score was higher in IGHD than CO (p=0.041), but severe NAFLD was not observed in any IGHD (or CO) individual. Conclusions: liver HP score is increased in lifetime untreated congenital IGHD, but the increase in transaminases is mild, suggesting lack of advanced forms of NAFLD.
Full-text · Article · Aug 2014 · Endocrine Connections
[Show abstract][Hide abstract] ABSTRACT: Objectives:
GH therapy is still controversial, except in severe GH deficiency (SGHD). The objective of this study was to compare the response to growth hormone (GH) therapy in children with partial GH insensitivity (PGHIS) and mild GH deficiency (MGHD) with those with SGHD.
Subjects and methods:
Fifteen PGHIS, 11 MGHD, and 19 SGHD subjects, followed up for more than one year in the Brazilian public care service, were evaluated regarding anthropometric and laboratory data at the beginning of treatment, after one year (1st year) on treatment, and at the last assessment (up to ten years in SGHD, up to four years in MGHD, and up to eight years in PGHIS).
Initial height standard deviation score (SDS) in SGHD was lower than in MGHD and PGHIS. Although the increase in 1 st year height SDS in comparison to initial height SDS was not different among the groups, height-SDS after the first year of treatment remained lower in SGHD than in MGHD. There was no difference in height-SDS at the last assessment of the children among the three groups. GH therapy, in the entire period of observation, caused a trend towards lower increase in height SDS in PGHIS than SGHD but similar increases were observed in MGHD and SGHD.
GH therapy increases height in PGHIS and produces similar height effects in MGHD and SGHD.
No preview · Article · Feb 2014 · Arquivos brasileiros de endocrinologia e metabologia
[Show abstract][Hide abstract] ABSTRACT: Context:The GH/IGF-I axis is important for bone growth, but its effects on joint function are not completely understood. Adult-onset GH-deficient individuals have often reduced bone mineral density (BMD). However, there are limited data on BMD in adult patients with untreated congenital isolated GH-deficient (IGHD). We have shown that adult IGHD individuals from the Itabaianinha, homozygous for the c.57+1G>A GHRHR mutation, have reduced bone stiffness, but BMD and joint status in this cohort are unknown.Objective:To study BMD, joint function, and osteoarthritis score in previously untreated IGHD adults harboring the c.57+1G>A GHRHR mutation.Design:Cross-sectional.Methods:Areal BMD by dual-energy X-ray absorptiometry was measured in 25 IGHD and 23 controls (CO). Volumetric BMD (vBMD) was calculated at the lumbar spine and total hip. Joint function was assessed by goniometry of elbow, hips, and knees. X-rays were used to measure the anatomic axis of knee and the severity of osteoarthritis, using a classification for osteophytes (OP) and joint space narrowing (JSN).Results:Genu valgum was more prevalent in IGHD than CO. The osteoarthritis knees OP score was similar in both groups, and knees JSN score showed a trend to be higher in IGHD. The hips OP score and JSN score were higher in IGHD. Areal BMD was lower in IGHD than CO, but vBMD was similar in the two groups. Range of motion was similar in elbow, knee, and hip in IGHD and CO.Conclusions:Untreated congenital IGHD due to a GHRHR mutation causes hip joint problems and genu valgum, without apparent clinical significance, reduces bone size, but does not reduce vBMD of the lumbar spine and hip.
No preview · Article · Sep 2013 · The Journal of Clinical Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: Adult subjects with untreated, lifetime, isolated GH deficiency (IGHD) due to a homozygous GHRH receptor gene mutation (MUT/MUT) residing in Itabaianinha, Brazil, present with lower BMI, higher prevalence of impaired glucose tolerance (IGT), increased insulin sensitivity (IS), and reduced β-cell function (βCF) when compared with non-BMI-matched homozygous normal controls. However, the prevalence of diabetes mellitus (DM) in this cohort is unknown. Comparing their IS and βCF with BMI-matched individuals heterozygous for the same mutation (MUT/N) may be useful to elucidate the role of the GH-IGF1 axis in IS and βCF. The purposes of this work were to verify the prevalence of IGT and DM in adult MUT/MUT subjects from this kindred and to compare IS and βCF in MUT/MUT and MUT/N.
We studied most (51) of the living IGHD adults of this kindred who are GH naive. The oral glucose tolerance test (OGTT) could be performed in 34 subjects, fasting glucose was measured in 15, while two had a previous diagnosis of DM. The OGTT results of 24 MUT/MUT subjects were compared with those of 25 BMI-matched MUT/N subjects. IS was assessed by homeostatic model assessment of insulin resistance (HOMA-IR), quantitative IS check index, and oral glucose IS index for 2 and 3 h. βCF was assayed by HOMA-β, insulinogenic index, and the area under the curve of insulin:glucose ratio.
The prevalence of DM and IGT in IGHD was 15.68 and 38.23% respectively. IS was increased and βCF was reduced in MUT/MUT in comparison with MUT/N.
Lifetime, untreated IGHD increases IS, impairs βCF, and does not provide protection from diabetes.
Full-text · Article · Jun 2013 · Endocrine Connections
[Show abstract][Hide abstract] ABSTRACT: Growth hormone (GH) and prolactin share similarities in structure and function. We have previously shown that women with congenital isolated GH deficiency (IGHD) caused by a homozygous mutation in the GHRH receptor gene (GHRHR) (MUT/MUT) have a short reproductive life, with anticipated climacteric. At climacteric, they have lower prolactin levels than normal controls (N/N). Because they are able to breast feed, we hypothesized that this prolactin reduction is limited to climacteric, as result of lower estradiol exposure of the lactotrophs. The purposes of this work were to assess prolactin levels in broader age adults homozygous and heterozygous (MUT/N) for the mutation and in normal controls (N/N), and to correlate them to sex steroids levels. We enrolled 24 GH-naïve MUT/MUT (12 female), 25 MUT/N (14 female), and 25 N/N (11 female) subjects, aged 25-65 years. Anthropometric data and serum prolactin, estradiol, total testosterone, and sex hormone binding globulin (SHBG) were measured. Free testosterone was calculated. Prolactin levels were similar in the three groups. In males, testosterone and SHBG levels were higher in MUT/MUT in comparison to N/N. There was no difference in free testosterone among groups. In all 74 individuals, prolactin correlated inversely with age (p < 0.0001) and directly with serum estradiol (p = 0.018). Prolactin levels in subjects with IGHD due to a homozygous GHRHR mutation are similar to heterozygous and normal homozygous, but total testosterone and SHBG are higher in male MUT/MUT, with no difference in free testosterone. The reduced prolactin level is limited to climacteric period, possibly due to reduced estrogen exposure.
[Show abstract][Hide abstract] ABSTRACT: GH reduces insulin sensitivity (IS), whereas IGF-I increases it. IGF-I seems to be critical for the development of the β-cells, and impaired IS has been reported in GH deficiency (GHD).
The aim of the study was to assess IS and β-cell function in adult patients with untreated isolated GHD (IGHD) due to a homozygous mutation in the GHRH receptor gene.
We conducted a cross-sectional study in 24 GH-naive adult IGHD subjects and 25 controls.
We performed an oral glucose tolerance test with glucose and insulin measurements at 0, 30, 60, 90, 120, and 180 min.
IS was assessed by homeostasis model assessment index of insulin resistance (IR), quantitative IS check index, oral glucose IS in 2 h (OGIS2) and 3 h (OGIS3). β-Cell function was assayed by homeostasis model assessment index-β, insulinogenic index, and area under the curve of insulin-glucose ratio.
During the oral glucose tolerance test, glucose levels were higher in IGHD subjects (P<0.0001), whereas insulin response presented a trend toward reduction (P=0.08). The number of individuals with impaired glucose tolerance was higher in the IGHD group (P=0.001), whereas the frequency of diabetes was similar in the two groups. Homeostasis model assessment index of IR was lower (P=0.04), and quantitative IS check index and OGIS2 showed a nonsignificant trend toward elevation (P=0.066 and P=0.09, respectively) in IGHD. OGIS3 showed no difference between the groups. Homeostasis model assessment index-β, insulinogenic index, and ratio of the areas of the insulin and glucose curves were reduced in the IGDH group (P=0.015, P<0.0001, and P=0.02, respectively).
Adult subjects with lifetime congenital untreated IGHD present reduced β-cell function, no evidence of IR, and higher frequency of impaired glucose tolerance.
Full-text · Article · Dec 2011 · The Journal of Clinical Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: Conflicting data exist on the effects of GH replacement therapy (GHRT) on thyroid function and thyroid volume (TV) in GH-deficient (GHD) patients.
The aim of this study was to assess the effects of GHRT on thyroid function and TV in adults with congenital lifetime isolated GHD (IGHD).
We studied 20 GH-naïve adults with IGHD due to a homozygous mutation of the GHRH-receptor gene at baseline, after 6-month depot- GH replacement therapy (pGH), and 6-month washout (6mo). Total T(3), free T(4) (FT(4)), reverse T(3) (rT(3)), TSH, IGF-I, SHBG, and TV were measured; body surface area-corrected TV (CTV) was calculated.
IGF-I and T(3) increased pGH. T(3) levels remained elevated at 6mo. GHRT did not significantly change FT(4), rT(3), TSH, and SHBG. TV and CTV increased pGH and remained elevated at 6mo.
GHRT in IGHD adults caused an increase in serum T(3) levels and TV, suggesting an important role of the GH-IGF-I axis in thyroid function.
No preview · Article · Mar 2011 · Journal of endocrinological investigation
[Show abstract][Hide abstract] ABSTRACT: Deficiency of 21-hydroxylase is the most common form of congenital adrenal hyperplasia (CAH-21OH). The aim of this study was to determine, by allele-specific PCR, the frequency of microconversions of the CYP21A2, in sixteen patients with the classical forms and in 5 patients with the nonclassical (NC) form of CAH-21OH and correlate genotype with phenotype.
Genotypes were classified into 3 mutation groups (A, B and C), based on the degree of enzymatic activity. Screening for 7 microconversions by allele-specific PCR diagnosed 74.3% (n=26) of the 35 unrelated alleles.
The most frequent mutations were Q318X (25.7%), V281L (17.1%), I2 Splice (14.3%), I172N (14.3%), and R356W (14.3%). Genotype was identified in 57.1% of the patients. We observed correlation between genotype and phenotype in 91.7% of the cases.
The highest frequency for Q318X (25.7%) when compared to other studies may reflect individual sample variations in this Northeastern population.
Preview · Article · Mar 2009 · Arquivos brasileiros de endocrinologia e metabologia
[Show abstract][Hide abstract] ABSTRACT: GH deficiency (GHD) in adults is associated with increased abdominal adiposity and systolic blood pressure, total and low-density lipoprotein cholesterol, and C-reactive protein.
We have studied the effects of 6-month GH replacement therapy in 20 adult members of a large Brazilian kindred with lifelong severe and isolated GHD due to a homozygous mutation in GHRH receptor gene (46 +/- 14.5 yr; 122 +/- 7.7 cm; 36.7 +/- 5.4 kg; 10 men). Subjects were studied at baseline, after 6-month bimonthly depot GH injections (Nutropin Depot; Genentech, Inc., South San Francisco, CA) [post GH (pGH)], and after 6- and 12-month washout.
Despite modest trough serum IGF-I increase, GH replacement therapy caused a decrease in skinfolds and in waist-hip ratio, with a rebound increase at 12 months. Total and low-density lipoprotein cholesterol were reduced pGH and returned to baseline at 6 months. High-density lipoprotein cholesterol increased pGH, but at 12 months was lower than baseline. A progressive increase in left ventricular mass index, posterior wall, and septum thickness occurred from pGH to 12 months, and of carotid intima-media thickness, from 6 to 12 months. Individuals were 6, 16, and 52 times more likely to have an atherosclerotic carotid plaque at pGH, 6 and 12 months, respectively, when compared with baseline.
In patients with lifetime isolated GHD, 6-month treatment with GH has reversible beneficial effects on body composition and metabolic profile, but it causes a progressive increase in intima-media thickness and in the number of atherosclerotic carotid plaques.
Full-text · Article · Jan 2008 · Journal of Clinical Endocrinology & Metabolism
[Show abstract][Hide abstract] ABSTRACT: Biallelic mutations in the GHRH receptor (GHRHR) gene (GHRHR) are a frequent cause of isolated GH deficiency (IGHD). Although heterozygous carriers of these mutations appear normal, we hypothesized that heterozygosity for a GHRHR mutation might be associated with a subclinical phenotype.
We studied members of a large Brazilian kindred with IGHD (Itabaianinha cohort) caused by a homozygous null GHRHR mutation. We compared 76 adult subjects (age, 25-75 yr) heterozygous for the mutation (WT/MT) with 77 sex-matched controls from the same population who are homozygous for the wild-type GHRHR allele (WT/WT).
We found no difference in adult height and sd score for serum IGF-I between the two groups. Body weight, body mass index, skin folds, waist and hip circumferences, and lean mass were all reduced in WT/MT subjects. Percentage fat mass and waist/hip ratio were similar in the two groups. Fasting insulin and homeostasis model assessment of insulin resistance were lower in WT/MT. The other biochemical parameters [total and fractionated cholesterol, triglycerides, lipoprotein (a), and C-reactive protein] were not different between the two groups.
Heterozygosity for a null GHRHR mutation is not associated with reduction in adult stature or in serum IGF-I but is associated with changes in body composition and possibly an increase in insulin sensitivity. These effects do not seem to be modulated by changes in circulating IGF-I.