Gad B. Kletter

Congenital adrenal hypoplasia and isolated gonadotropin deficiency

Abstract Congenital adrenal hypoplasia with gonadotropin deficiency is a rare X-linked recessive disorder that usually manifests with symptoms of adrenal insufficiency early in infancy. Adequate replacement therapy with glucocorticoids, mineralocorticoids, and salt has resulted in an increased survival. Slow growth and failure to undergo sexual maturation during the adolescent years usually ensues, secondary to hypogonadotropic hypogonadism. The X-linked congenital adrenal hypoplasia locus has been mapped to region Xp21.3-p21.2. Interstitial deletions of the X chromosome overlapping this region have been observed to cause complex clinical problems, with adrenal hypoplasia as a prominent component. Within a family segregating the disease, there is a 50% risk of having an affected male and a 50% risk of having a carrier female; considerations of genetic heterogeneity, possible chromosomal abnormalities, and prenatal diagnostic studies warrant medical genetic evaluations. The following case presentations illustrate the clinical spectrum of this condition.

Autosomal dominant transmission of the Pallister-Hall syndrome

We describe a 9-year-old boy and his 34-year-old father with the Pallister-Hall syndrome. The proband had precocious puberty, imperforate anus, postaxial polydactyly, hypospadias, a hypothalamic mass, and a displaced pituitary gland. The father had polydactyly, a hypothalamic mass, and a flattened pituitary gland. We conclude that the most likely cause of the Pallister-Hall syndrome is a mutation in a gene inherited in an autosomal dominant manner.

Results of a Second Year of Therapy with the 12-Month Histrelin Implant for the Treatment of Central Precocious Puberty

Background. Gonadotropin releasing hormone analogs (GnRHas) are standard of care for central precocious puberty (CPP). The histrelin subcutaneous implant is safe and effective in the treatment of CPP for one year. Objective. The study evaluates a second year of therapy in children with CPP who received a new implant after one year of treatment. Methods. A prospective one-year study following an initial 12-month treatment period was conducted. Results. Thirty-one patients (29 girls) aged years received a second implant. Eighteen were naïve to GnRHa therapy at first implantation. Peak LH declined from  mIU/mL at 12 months to  mIU/mL at 24 months (< .0001) in naïve subjects, and from  mIU/mL at 12 months to  mIU/mL at 24 months () in previously treated subjects. Predicted adult height increased by 5.1 cm at 24 months (). Minor implant site reactions occurred in 61%, while minor difficulties with explantation occurred in 32.2% of subjects. Conclusion. The histrelin implant demonstrates profound hypothalamic-pituitary-gonadal axis suppression when a new implant is placed for a second year of treatment. Prospective follow-up of this therapeutic modality for the treatment of CPP is needed.

Serum bioactive luteinizing and follicle-stimulating hormone concentrations in girls increase during puberty.

ABSTRACT: FSH plays an essential role in folliculogenesis and ovarian growth. However, cross-sectional studies have not shown an increase in bioactive FSH (B-FSH) during puberty. To eliminate intersubject variability, we used a longitudinal design and tested the hypothesis that B-FSH increases during puberty. Thirty normal, healthy girls were enrolled in a longitudinal study from pubertal stages I to IV. The subjects were evaluated at 6-mo intervals; each visit consisted of pubertal staging, bone age determination by x-ray, measurements of serum immuno-reactive FSH (I-FSH) and B-FSH (n = 14) or immunoreactive LH (I-LH) and bioactive LH (B-LH) (n = 18), and adrenal and ovarian steroids. All girls had clinical and hormonal characteristics of puberty. Both I-FSH and B-FSH levels were relatively elevated before puberty, whereas serum I-LH and B-LH were low. From pubertal stages I to III, there was a modest yet significant rise in serum I-FSH (p < 0.001) and serum B-FSH (p < 0.01). Serum I-LH and B-LH concentrations showed the expected increases with puberty (p < 0.001), with serum B-LH concentrations exhibiting a greater rise than I-LH (p < 0.001). Our results demonstrate that serum B-FSH and I-FSH increase during puberty. Relatively elevated B-FSH concentrations from early to midpuberty may be an important factor for ovarian growth while circulating LH and estrogen are still low. As puberty progresses, the continued and selective increase in LH induces a rise in estradiol and ultimately leads to ovulation.

Growth hormone bioactivity in girls with turner's syndrome: Correlation with insulin-like growth factor I

ABSTRACT: We have recently developed a new bioassay for growth hormone (GH) in serum, which is based on the ability of GH to suppress glucose use in cultured murine adipocytes. We tested the hypothesis that bioactive GH (B-GH) concentrations would correlate better with the GH-dependent peptides, IGF-I, and IGF-binding protein-3 (IGFBP-3) than would GH determined by conventional RIA (RIA-GH). Twenty-five girls with Turners syndrome were studied. The subjects had ages ranging from 4.8 to 15.9 y and height SD from the mean (SD score) ranging from −0.77 to −5.67. Blood samples were obtained every 15 or 20 min for 12 h overnight. For each girl, an equal aliquot of each overnight sample was pooled for determination of B-GH, RIA-GH, IGF-I, IGFBP-3, LH, FSH, and estradiol. Measurable estradiol concentrations were present in six girls and were sufficient to suppress gonad-otropin concentrations in two girls, but they did not alter B-GH, RIA-GH, IGF-I, and IGFBP-3 concentrations compared with the age-matched girls without measurable estradiol concentrations. Hence, data for all girls were combined for subsequent regression analyses. RIA-GH did not correlate significantly with B-GH, IGF-I, or IGFBP-3. B-GH exhibited a significant correlation with IGF-I (r = 0.407, p < 0.05), and the correlation with IGFBP-3 was better than that for RIA-GH (r = 0.355 versus 0.064, B-GH and RIA-GH, respectively). None of the B-GH, RIA-GH, IGF-I, or IGFBP-3 concentrations had a significant correlation with height SD score or height velocity SD score. These results indicate that B-GH correlates better with the GH-dependent peptides, IGF-I and IGFBP-3, than does RIA-GH, but neither measure of GH is useful in predicting height in girls with Turners syndrome.

A Randomized Safety and Efficacy Study of Somavaratan (VRS-317), a Long-Acting rhGH, in Pediatric Growth Hormone Deficiency

CONTEXT Somavaratan (VRS-317) is a long-acting form of recombinant human GH under development for children and adults with GH deficiency (GHD). OBJECTIVES To determine the optimal somavaratan dose regimen to normalize IGF-1 in pediatric GHD and to evaluate safety and efficacy of somavaratan over 6 months. DESIGN Open-label, multicenter, single ascending dose study followed by 6-month randomized comparison of 3 dosing regimens. SETTING Twenty-five United States pediatric endocrinology centers. PATIENTS Naive-to-treatment, prepubertal children with GHD (n = 68). INTERVENTION(S) Patients received single sc doses of somavaratan (0.8, 1.2, 1.8, 2.7, 4.0, or 6.0 mg/kg) during the 30-day dose-finding phase, then were randomized to somavaratan 1.15 mg/kg weekly, 2.5 mg/kg twice monthly, or 5.0 mg/kg monthly for 6 months. MAIN OUTCOME MEASURES Safety, pharmacokinetics, pharmacodynamics, 6-month height velocity (HV). RESULTS Somavaratan pharmacokinetics was linearly proportional to dose; dose-dependent increases in the magnitude and duration of IGF-1 responses enabled weekly, twice-monthly or monthly dosing. A single dose of somavaratan sustained IGF-1 responses for up to 1 month. No somavaratan or IGF-1 accumulation occurred with repeat dosing. Mean annualized HVs for somavaratan administered monthly, twice monthly, or weekly (7.86 ± 2.5, 8.61 ± 2.7, and 7.58 ± 2.5 cm/y, respectively) were similar between groups. Adverse events were mostly mild and transient. CONCLUSIONS Somavaratan demonstrated clinically meaningful improvements in HV and IGF-1 in prepubertal children with GHD, with no significant differences between monthly, twice-monthly, or weekly dosing.

Gonadotropin-releasing hormone agonist analog (nafarelin): a useful diagnostic agent for the distinction of constitutional growth delay from hypogonadotropic hypogonadism.

To determine the usefulness of a GnRH agonist analog as a diagnostic test to distinguish between constitutional delay of growth (CGD) in boys with Tanner stage I of sexual development and patients with hypogonadotropic hypogonadism (HH), we evaluated six boys (mean age 15 yr 4 m) and five HH patients (mean age 20 yr 4 m). In addition, 20 normal healthy men aged 21 yr to 50 yr received either nafarelin or GnRH followed two weeks later by the other test in order to compare the efficacy of each of these tests and to evaluate the optimal sampling times for the nafarelin test. All subjects were healthy, and had not received hormonal replacement for at least 2 months prior to enrollment in the study. Each man had four baseline blood samples before and at timed intervals following the administration of either GnRH or nafarelin. Each of the patients had blood withdrawn every 15 min during 12 h overnight followed by a single s.c. injection of nafarelin (1 microgram(s)/kg up to 100 microgram(s)), except two HH patients who did not have an overnight study. Blood samples were obtained at timed intervals for 24 h. LH, FSH, T and E2 were measured by RIA. Baseline concentrations of plasma LH, FSH and T were similar before the administration of either GnRH or nafarelin in the group of normal men. Peak stimulation of plasma LH, FSH and T released by nafarelin was significantly higher, and it took a longer time to reach the peak maximum, than after GnRH (p < 0.001). Mean nocturnal LH was 5.5 +/- 0.9 IU/I for the CGD group, and 2.7 +/- 0.7 IU/I for HH (p < 0.02). Mean nocturnal FSH was 5.1 +/- 1.0 and 2.5 +/- 0.2 IU/I whereas mean nocturnal T concentrations were 4.2 +/- 0.8 and 0.7 +/- 0.2 nmol/I (CGD vs HH, respectively, p < 0.02). Peak LH responses to nafarelin were 36.9 +/- 8.9 IU/I for the CGD group, and 7.0 +/- 2.0 IU/I for the HH group (p < 0.001). Peak FSH released by nafarelin was 14.2 +/- 2.4 IU/I for the CGD group and 4.8 +/- 2.0 IU/I for the HH group (p < 0.02). Peak T was reached 24 h following nafarelin injection and was 5.7 +/- 1.7 nmol/I for the CGD group and 0.3 +/- 0.2 nmol/I for the HH group (p < 0.001). The results obtained indicate that in early stages of puberty (before detectable changes of sexual maturation) the nafarelin test, with measurements of LH, FSH and T in blood or in urine, is superior to and more practical than overnight hormonal estimates to clearly distinguish CGD from HH.

Evaluation of gonadotropin responses to synthetic gonadotropin-releasing hormone in girls with idiopathic hypopituitarism

We hypothesized that prepubertal girls with gonadotropin deficiency would produce less follicle-stimulating hormone (FSH) in response to synthetic gonadotropin-releasing hormone (GnRH) than would gonadotropin-sufficient children. To test this hypothesis, we performed 103 GnRH tests serially in 21 children who had idiopathic hypopituitarism with growth hormone deficiency. We tried to predict whether puberty would occur in the 17 girls with bone ages of 8 years or less. Of these 17 girls, 4 failed to have spontaneous secondary sexual characteristics by age 16 1/2 years, and 12 had spontaneous complete pubertal development. One girl had incomplete pubertal maturation with partial gonadotropin deficiency; her results were combined with those of the girls who had no spontaneous pubertal development. With increasing bone age, the girls with complete pubertal development had a decrease in the increment of FSH released in response to GnRH, although basal gonadotropin concentrations did not change. For GnRH tests performed at bone ages of 8 years or less, basal luteinizing hormone (LH) values did not differ between girls with complete puberty and those with absent or incomplete puberty. However, basal FSH and the incremental response of LH and FSH to GnRH were greater in those with complete puberty. Only two girls with prepubertal bone ages at the time of testing, who subsequently had complete puberty, had incremental FSH responses to GnRH that were less than 5 IU/L. Individual incremental LH responses to GnRH did not discriminate well between groups. None of the girls with adrenocorticotropic hormone deficiency, either originally or subsequently, had spontaneous puberty, but 4 of 12 girls with thyrotropin deficiency, either originally or subsequently, had complete puberty. We conclude that a significant increase in GnRH-stimulated FSH suggests that spontaneous pubertal development will occur in girls with idiopathic hypopituitarism. However, a low FSH response to GnRH may not be diagnostic of gonadotropin deficiency.

ELEVATED SERUM IRON LEVELS FOLLOWING ADMINISTRATION OF CISPLATINUM

An increase in serum iron levels and a decrease in serum unsaturated iron binding capacity (uIBC) were noted following the administration of cisplatinum to 9 children with malignancies. The mean serum iron concentration increased from a pretreatment level of 75.7±30.5 ug/ml to a post treatment level of 162.1±65.3 ug/ml with the first cisplatinum treatment course(p<0.004). The uIBC concomittantly decreased from 181.9±33.7 ug/ml to 86.4 ± 44.6 ug/ml(p<0.0005). Cummulative effect was noted following subsequent courses. The levels returned to baseline values within 2-4 months following cessation of therapy in 6 children in whom follow up data was available. It is possible that this reversal of the iron/uIBC ratio is the result of cisplatinum competition for iron binding sites to proteins.

PUBERTAL INCREASE IN IFMA-GH IS NOT ACCOMPANIED BY AN INCREASE IN BIOACTIVE GH IN CHILDREN UNTIL LATE STAGES OF PUBERTY. |[dagger]| 501

With advancing puberty, there is a remarkable acceleration of growth in both sexes. To test the hypothesis that pubertal growth may be associated with secretion of biologically more potent GH in addition to a quantitative increase in GH secretion, we measured overnight GH by immunofluorometric assay(IFMA) and GH-bioactivity (Bio-GH) in 42 boys and 21 girls with constitutional delay of growth. Blood samples were obtained every 20 minutes from 20:00 to 08:00h and an equal aliquot of each sample from a patient was pooled for analysis of IFMA-GH, Bio-GH, LH, FSH, testosterone, estradiol, and IGF-I. Bio-GH was determined by measuring suppression of lipid accumulation in cultured murine 3T3-F442A adipocytes. For comparison, boys and girls were divided into groups according to pubertal stage. Data was analyzed by ANOVA after logarithmic transformation. IFMA-GH and Bio-GH declined in prepubertal boys with a bone age of ≥9 yrs when they were about to start puberty, compared to prepubertal boys with younger bone age. After this decline mean IFMA-GH increased becoming maximal in stage III puberty. Bio-GH did not increase until the very late stages of puberty in both sexes. The discrepancy between IFMA- and Bio-GH suggests that there may be isoform differences in GH secreted at different stages of puberty representing changes in pituitary synthesis or post-secretion modifications (Supported by Genentech Foundation for Growth & Development). Table