Case report: Novel SIN3A loss-of-function variant as causative for hypogonadotropic hypogonadism in Witteveen-Kolk syndrome

Pubertal delay can be due to hypogonadotropic hypogonadism (HH), which may occur in association with anosmia or hyposmia and is known as Kallmann syndrome (OMIM #308700). Recently, hypogonadotropic hypogonadism has been suggested to overlap with Witteveen-Kolk syndrome (WITKOS, OMIM #613406) associated with 15q24 microdeletions encompassing SIN3A. Whether hypogonadotropic hypogonadism is due to haploinsufficiency of SIN3A or any of the other eight genes present in 15q24 is not known. We report the case of a female patient with delayed puberty associated with intellectual disability, behavior problems, dysmorphic facial features, and short stature, at the age of 14 years. Clinical, laboratory, and imaging assessments confirmed the diagnosis of Kallmann syndrome. Whole-exome sequencing identified a novel heterozygous frameshift variant, NM_001145358.2:c.3045_3046dup, NP_001138830.1:p.(Ile1016Argfs*6) in SIN3A, classified as pathogenic according to the American College of Medical Genetics and Genomics (ACMG/AMP) criteria. Reverse phenotyping led to the clinical diagnosis of WITKOS. No other variant was found in the 96 genes potentially related to hypogonadotropic hypogonadism. The analysis of the other contiguous seven genes to SIN3A in 15q24 did not reveal any clinically relevant variant. In conclusion, these findings point to SIN3A as the gene in 15q24 related to the reproductive phenotype in patients with overlapping WITKOS and Kallmann syndrome.

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.

An in vivo functional assay to characterize human STAT5B genetic variants during zebrafish development

Growth hormone (GH) binding to GH receptor activates janus kinase 2 (JAK2)-signal transducer and activator of transcription 5b (STAT5b) pathway, which stimulates transcription of insulin-like growth factor-1 (IGF1), insulin-like growth factor binding protein 3 (IGFBP3) and insulin-like growth factor acid-labile subunit (IGFALS). Although STAT5B deficiency was established as an autosomal recessive disorder, heterozygous dominant-negative STAT5B variants have been reported in patients with less severe growth deficit and milder immune dysfunction. We developed an in vivo functional assay in zebrafish to characterize the pathogenicity of three human STAT5B variants (p.Ala630Pro, p.Gln474Arg and p.Lys632Asn). Overexpression of human wild-type (WT) STAT5B mRNA and its variants led to a significant reduction of body length together with developmental malformations in zebrafish embryos. Overexpression of p.Ala630Pro, p.Gln474Arg or p.Lys632Asn led to an increased number of embryos with pericardial edema, cyclopia and bent spine compared with WT STAT5B. Although co-injection of WT and p.Gln474Arg and WT and p.Lys632Asn STAT5B mRNA in zebrafish embryos partially or fully rescues the length and the developmental malformations in zebrafish embryos, co-injection of WT and p.Ala630Pro STAT5B mRNA leads to a greater number of embryos with developmental malformations and a reduction in body length of these embryos. These results suggest that these variants could interfere with endogenous stat5.1 signaling through different mechanisms. In situ hybridization of zebrafish embryos overexpressing p.Gln474Arg and p.Lys632Asn STAT5B mRNA shows a reduction in igf1 expression. In conclusion, our study reveals the pathogenicity of the STAT5B variants studied.

Delayed Puberty Phenotype Observed in Noonan Syndrome Is More Pronounced in Girls than Boys

INTRODUCTION

Pubertal delay is described as one of the clinical features in Noonan syndrome (NS) and it may be one of the factors causing short adult height in those patients. The present study aimed at characterizing pubertal development in NS and identifying pubertal delay predictors.

METHODS

We analyzed 133 individuals with a molecular diagnosis of NS and clinical puberty evaluation. We characterized delayed puberty as pubertal onset after 12 years in girls and 13.5 years in boys, according to parameters of the Brazilian population. To investigate its predictors, we correlated the age at onset of puberty with several characteristics and genotype in a multilevel regression model. For comprehending pubertal development in NS, we assessed age and anthropometric measures at each Tanner stage and adult age.

RESULTS

The mean age at puberty onset for girls was 11.9 ± 1.9 years and for boys, 12.5 ± 1.7 years, significantly later than the Brazilian population (p = 0.025; p < 0.001). Girls (49.1%) presented delayed puberty more frequently than boys (27.9%, p = 0.031). Body mass index standard deviation scores (SDS) and insulin growth factor 1 SDS at puberty onset significantly predicted later puberty entry. Height gain from the onset of puberty to adult height was lower in children with pubertal delay.

CONCLUSION

Pubertal delay is characteristically found in children with NS, more frequently in females. The low weight of patients with NS could modulate the age of puberty, just as the increase in overweight/obesity in the general population has shown an effect on reducing the age of onset of puberty.

High-throughput splicing assays identify missense and silent splice-disruptive POU1F1 variants underlying pituitary hormone deficiency

Pituitary hormone deficiency occurs in ∼1:4,000 live births. Approximately 3% of the cases are due to mutations in the alpha isoform of POU1F1, a pituitary-specific transcriptional activator. We found four separate heterozygous missense variants in unrelated individuals with hypopituitarism that were predicted to affect a minor isoform, POU1F1 beta, which can act as a transcriptional repressor. These variants retain repressor activity, but they shift splicing to favor the expression of the beta isoform, resulting in dominant-negative loss of function. Using a high-throughput splicing reporter assay, we tested 1,070 single-nucleotide variants in POU1F1. We identified 96 splice-disruptive variants, including 14 synonymous variants. In separate cohorts, we found two additional synonymous variants nominated by this screen that co-segregate with hypopituitarism. This study underlines the importance of evaluating the impact of variants on splicing and provides a catalog for interpretation of variants of unknown significance in POU1F1.

Comprehensive Identification of Pathogenic Gene Variants in Patients With Neuroendocrine Disorders

PURPOSE

Congenital hypopituitarism (CH) can present in isolation or with other birth defects. Mutations in multiple genes can cause CH, and the use of a genetic screening panel could establish the prevalence of mutations in known and candidate genes for this disorder. It could also increase the proportion of patients that receive a genetic diagnosis.

METHODS

We conducted target panel genetic screening using single-molecule molecular inversion probes sequencing to assess the frequency of mutations in known hypopituitarism genes and new candidates in Argentina. We captured genomic deoxyribonucleic acid from 170 pediatric patients with CH, either alone or with other abnormalities. We performed promoter activation assays to test the functional effects of patient variants in LHX3 and LHX4.

RESULTS

We found variants classified as pathogenic, likely pathogenic, or with uncertain significance in 15.3% of cases. These variants were identified in known CH causative genes (LHX3, LHX4, GLI2, OTX2, HESX1), in less frequently reported genes (FOXA2, BMP4, FGFR1, PROKR2, PNPLA6) and in new candidate genes (BMP2, HMGA2, HNF1A, NKX2-1).

CONCLUSION

In this work, we report the prevalence of mutations in known CH genes in Argentina and provide evidence for new candidate genes. We show that CH is a genetically heterogeneous disease with high phenotypic variation and incomplete penetrance, and our results support the need for further gene discovery for CH. Identifying population-specific pathogenic variants will improve the capacity of genetic data to predict eventual clinical outcomes.

A novel heterozygous STAT5B variant in a patient with short stature and partial growth hormone insensitivity (GHI)

BACKGROUND

The most frequent monogenic causes of growth hormone insensitivity (GHI) include defects in genes encoding the GH receptor itself (GHR), the signal transducer and activator of transcription (STAT5B), the insulin like-growth factor type I (IGF1) and the acid-labile subunit (IGFALS). GHI is characterized by a continuum of mild to severe post-natal growth failure.

OBJECTIVE

To characterize the molecular defect in a patient with short stature and partial GHI.

PATIENT AND METHODS

The boy was born at term adequate for gestational age from non-consanguineous normal-stature parents. At 2.2 years, he presented proportionate short stature (height -2.77 SDS), wide forehead and normal mental development. Whole-exome analysis and functional characterization (site-directed mutagenesis, dual luciferase reporter assay, immunofluorescence and western immunoblot) were performed.

RESULTS

Biochemical and endocrinological evaluation revealed partial GH insensitivity with normal stimulated GH peak (7.8 ng/mL), undetectable IGF1 and low IGFBP3 levels. Two heterozygous variants in the GH-signaling pathway were found: a novel heterozygous STAT5B variant (c.1896G>T, p.K632N) and a hypomorphic IGFALS variant (c.1642C>T, p.R548W). Functional in vitro characterization demonstrated that p.K632N-STAT5b is an inactivating variant that impairs STAT5b activity through abolished phosphorylation. Remarkably, the patient's immunological evaluation displayed only a mild hypogammaglobulinemia, while a major characteristic of STAT5b deficient patients is severe immunodeficiency.

CONCLUSIONS

We reported a novel pathogenic inactivating STAT5b variant, which may be associated with partial GH insensitivity and can present without severe immunological complications in heterozygous state. Our results contribute to expand the spectrum of phenotypes associated to GHI.

p.R209H GH1 variant challenges short stature assessment

OBJECTIVE

to describe the marked variability in clinical and biochemical patterns that are associated with a p.R209H GH1 missense variant in a large Argentinean pedigree, which makes the diagnosis of GHD elusive.

DESIGN

We describe a non-consanguineous pedigree composed by several individuals with short stature, including 2 pediatric patients with typical diagnosis of isolated growth hormone deficiency (IGHD) and 4 other siblings with severe short stature, low serum IGF-1 and IGFBP-3, but normal stimulated GH levels, suggesting growth hormone insensitivity (GHI) in the latter group.

RESULTS

Patients with classical IGHD phenotype carried a heterozygous variant in GH1: c.626G>A (p.R209H). Data from the extended pedigree suggested GH1 as the initial candidate gene, which showed the same pathogenic heterozygous GH1 variant in the four siblings with short stature and a biochemical pattern of GHI.

CONCLUSIONS

We suggest considering GH1 sequencing in children with short stature associated to low IGF-1 and IGFBP-3 serum levels, even in the context of normal response to growth hormone provocative testing (GHPT).

SUN-245 Heterozygous GH1 p.R209H Variant within a Large Pedigree May Mimic a Growth Hormone Insensitivity Pattern

Isolated growth hormone deficiency (IGHD) is most frequently caused by mutations in the GH1 gene. Pathogenic mutations in the GHRHR and GHSR have also been reported to cause IGHD. Individuals with IGHD type II present with variable clinical phenotype. Autosomal dominant GH1 p.R209H variant impairs GH secretion despite normal GH synthesis. The aim of this work is to expand the clinical and biochemical phenotype of heterozygous GH1 p.R209H missense mutation (previously known as p.R183H) in a large Argentinean pedigree. We report a non-consanguineous 4 generation pedigree. Two affected members showed classical IGHD phenotype: short stature (height -4.13 and -2.6 SD), low GH peak after arginine/clonidine provocative tests (3.6 and 2.6 ng/ml, cut-off value 4.7 ng/ml, GH IS 98/574, Immulite), non-detectable IGF-1, and low IGFBP-3 (-2.83 and -2.28 SD). Brain MRI showed anterior pituitary gland of 3.3 mm and 2.5 mm, respectively. The use of a customized panel for congenital hypopituitarism using single molecule molecular inversion probes sequencing (smMIPS) revealed a c.626G>A transition in GH1 gene, predicted to result in p.R209H mutation. The variant was subsequently confirmed by Sanger sequencing. Parents affected with the same variant presented either short (-1.91 SDS) or normal stature (-0.72 SDS). The patients’ response to rhGH treatment was adequate (Δ heights were 2.49 and 1.37 SDS in 2.4 and 1.0 year of treatment, respectively). Additionally, 4/9 siblings within this pedigree had short stature (mean height -2.48 ± 0.62 SD) with mild or no clinical phenotype of GHD, normal GH response to provocative pharmacologic tests (maximum GH peaks 5.46 to 10.9 ng/ml), associated to low serum IGF-1 (mean -3.27 ± 0.89 SD) and IGFBP3 (mean -2.61 ± 0.42 SD), resembling a pattern of growth hormone insensitivity (GHI). IGF-1 generation tests (GH dose 33 µg/kg.day) showed a mean increment in IGF-1 of 3.25 times over basal, confirming adequate GH sensitivity. Despite the absence of complete GHD phenotype, data from the extended pedigree suggested GH1 as the initial candidate gene, identifying the same pathogenic GH1 variant in these four siblings. Brain MRI showed normal height of the anterior pituitary gland (range 3.9 to 4.6 mm). Their affected father had normal stature (-1.69 SDS) with low serum IGF-1 (64 ng/mL). We have shown that members of a large pedigree affected with the p.R209H GH1 variant showed either a classical clinical and biochemical pattern of GHD or an initial biochemical pattern resembling GHI. This variability could lead in certain cases to an elusive diagnosis of GHD when the classical phenotype is absent. Therefore, these results highlight the need to explore GH1 gene in children with short stature associated to low IGF-1 and IGFBP-3 serum levels even when GH response to pharmacological tests is normal.

MON-472 Potentially Pathogenic Variants Identified in Patients with Hypopituitarism by Molecular Inversion Probe Sequencing (MIPS), a New Molecular Approach for Low Cost Gene Panel Sequencing

Congenital hypopituitarism occurs in 1/3,000 - 1/10,000 live births and is highly variable phenotypically. The condition is life-long and life-threatening if untreated. Diagnosis remains a challenge, particularly in the neonatal period. There is a need for better diagnosis that would lead to improved prognosis and treatment. We recently implemented a novel and cost-effective approach based on Molecular Inversion Probe Sequencing (MIPS) to identify novel variants and candidate genes in sporadic trios and familial cases of combined pituitary deficiency (CPHD) in the absence or presence of any midline defects or optic nerve hypoplasia, and isolated growth hormone deficiency (IGHD). We captured 693 coding exons of 30 known genes and 37 candidate genes from studies in mice. We captured genomic DNA from 181 pediatric patients with CPHD or IGHD and 115 relatives and conducted next generation sequencing. We obtained a 600X average coverage per sample over targeted regions. We scored rare variants as pathogenic, likely pathogenic, or variants with uncertain significance that are predicted to be damaging using at least 3 independent software programs. We identified such variants in known genes (GH1, GLI2, LHX3, LHX4, PNPLA6, and HESX1) and in new candidate genes that require additional evidence demonstrating causality (BMP2, ACVRL1 and WDR11). GLI2 heterozygous loss of function mutations have been reported in over 50 patients with CPHD and variable associated features. We identified a GLI2 p.Leu761Phe variant in a patient with a complex phenotype, including GH and antidiuretic hormone (ADH) deficiencies, hypoplasia of the anterior lobe, arachnoid cyst, right cerebellar hemisphere hypoplasia, myopia and astigmatism, neonatal insipidus diabetes, speech neurodevelopmental delay and mild left foot paresis. We performed functional assays in cell culture and preliminary results suggested that GLI2 p.Leu761Phe has a gain of function effect on transcription. We hypothesize that this mutation affects the acetylation of the nearby p.Lys757 by modifying the recognition site of p300 acetylase. Acetylation of GLI2 at this lysine is a critical regulated step, controlling the activation status of the Hedgehog pathway, which is a major regulator of embryonic development. Further work is needed to demonstrate this effect. In summary, using the first comprehensive screening panel for known genes and candidates for congenital hypopituitarism, we identified variants that are likely disease-causing in about 30% of the cases. Identifying pathogenic variants will make it feasible to predict clinical outcomes from genetic data, which is necessary for patient diagnosis and prognosis, and for assessing the risk of future affected individuals.

Partial growth hormone insensitivity and dysregulatory immune disease associated with de novo germline activating STAT3 mutations

Germinal heterozygous activating STAT3 mutations represent a novel monogenic defect associated with multi-organ autoimmune disease and, in some cases, severe growth retardation. By using whole-exome sequencing, we identified two novel STAT3 mutations, p.E616del and p.C426R, in two unrelated pediatric patients with IGF-I deficiency and immune dysregulation. The functional analyses showed that both variants were gain-of-function (GOF), although they were not constitutively phosphorylated. They presented differences in their dephosphorylation kinetics and transcriptional activities under interleukin-6 stimulation. Both variants increased their transcriptional activities in response to growth hormone (GH) treatment. Nonetheless, STAT5b transcriptional activity was diminished in the presence of STAT3 GOF variants, suggesting a disruptive role of STAT3 GOF variants in the GH signaling pathway. This study highlights the broad clinical spectrum of patients presenting activating STAT3 mutations and explores the underlying molecular pathway responsible for this condition, suggesting that different mutations may drive increased activity by slightly different mechanisms.

Circulating IGF-I, IGFBP-3 and the IGF-I/IGFBP-3 Molar Ratio Concentration and Height Outcome in Prepubertal Short Children on rhGH Treatment over Two Years of Therapy

OBJECTIVE

To investigate the occurrence of abnormally elevated values of biomarkers of growth hormone (GH) action in short children on recombinant human GH (rhGH) therapy.

METHODS

Sixty-three prepubertal short children were examined: 31 with GH deficiency (GHD), 25 small for gestational age (SGA), and 9 with Turner syndrome (TS). The main outcomes were the following: standard deviation score (SDS) values of IGF-I, IGFBP-3, and IGF-I/IGFBP-3 molar ratio before, at the 1st and at the 2nd year on rhGH and Δheight (Ht)-SDS to evaluate GH treatment efficacy (adequate 1st-year ΔHt SDS: >0.4 SDS for GHD and >0.3 SDS for non-GHD).

RESULTS

Seventy-eight percent of GHD, 78% of SGA and 55% of TS children had adequate 1st-year ΔHt SDS. In GHD, 88% of IGF-I SDS and IGFBP-3 SDS that were ≤-2.0 SDS at baseline normalized on treatment. Abnormal IGF-I values >+2.0 SDS were observed in 52% of SGA and in 55% of TS patients on rhGH. Within each group, the IGF-I/IGFBP-3 molar ratio increased significantly from pretreatment and throughout therapy, remaining within normal range for most patients. ΔIGF-I/IGFBP-3 molar ratio SDS were significantly higher in children with an adequate response (p < 0.01).

CONCLUSION

Non-GHD groups presented markedly elevated concentrations of GH biomarkers on rhGH and normal IGF-I/IGFBP-3 molar ratio in most patients. Since there is a lack of consensus regarding the molar ratio usefulness, we think that interventions towards a more physiological IGF-I serum profile should be implemented.

Pilot Neonatal Screening Program for Central Congenital Hypothyroidism: Evidence of Significant Detection

BACKGROUND/AIM

Congenital hypothyroidism (CH) is a heterogeneous entity. Neonatal screening programs based on thyrotropin (TSH) determination allow primary CH diagnosis but miss central CH (CCH). CCH causes morbidity, alerts to other pituitary deficiencies, and is more prevalent than previously thought. We aimed at developing a pilot neonatal screening program for CCH detection.

PATIENTS AND METHODS

A prospective 2-year pilot neonatal screening study based on simultaneous dried blood specimen TSH and thyroxine (T4) measurements was implemented in term newborns aged 2-7 days. Those with T4 ≤4.5 µg/dL (-2.3 SDS) and TSH <10 mIU/L were recalled (suspicious of CCH) and underwent clinical and biochemical assessment performed by expert pediatric endocrinologists.

RESULTS

A total of 67,719 newborns were screened. Primary CH was confirmed in 24 (1: 2,821). Forty-four newborns with potential CCH were recalled (recall rate 0.07%) at a mean age of 12.6 ± 4.8 days. In this group, permanent CCH was confirmed in 3 (1: 22,573), starting L-T4 treatment at a mean age of 12.3 ± 6.6 days; 14 boys showed T4-binding globulin deficiency (1: 4,837); 24 had transient hypothyroxinemia (21 non-thyroidal illness and 3 healthy); and 3 died before the confirmation stage. According to initial free T4 measurements, CCH patients had moderate hypothyroidism.

CONCLUSIONS

Adding T4 to TSH measurements enabled the identification of CCH as a prevalent condition and contributed to improving the care of newborns with congenital hypopituitarism and recognizing other thyroidal disorders.

Cognitive profiles of patients with early detected and treated congenital hypothyroidism

INTRODUCTION

Children with congenital hypothyroidism (CH) detected by newborn screening and adequately treated may have mild cognitive deficits. OBJECTIVES">To assess the intelligence quotient of children with CH and identify the presence of specific cognitive deficits.

POPULATION AND METHODS

A group of 60 children with CH detected by newborn screening, who were aged 9-10 years old and received adequate treatment since their first month of life was selected and compared to a control group of 60 children without CH in the same age range. Inclusion criteria: children without concurrent diseases, who were attending school in a single shift, and whose parents had at least completed secondary education. The following tests were administered during individual interviews: the Wechsler Intelligence Scale for Children (third edition), the Rey complex figure test, the Woodcock-Muñoz revised test, the Conners Continuous Performance Test II, the Illinois Test of Psycholinguistic Abilities, the verbal fluency test, the Knox Cube Test, the Trail Making Test, the faces test, and the 5 digit test. The statistical analysis was done using Student's t tests (for independent samples) with Bonferroni's correction (p < 0.002).

RESULTS

Even within the normal average range, significant differences were observed between both groups in terms of total intelligence quotient and performance intelligence quotient (small and moderate effect sizes, respectively). In terms of performance, children with hypothyroidism had a significantly poorer performance in processing speed, reaction times, attention, cognitive flexibility, visuoconstruction, and long-term memory. No significant differences were found between both groups in the verbal area.

CONCLUSIONS

Children with congenital hypothyroidism and without mental disability had mild cognitive deficits, which should be taken into account for a comprehensive patient care.

Hypogonadotropic Hypogonadism in Infants with Congenital Hypopituitarism: A Challenge to Diagnose at an Early Stage

BACKGROUND

Combined pituitary hormone deficiency (CPHD) presents a wide spectrum of pituitary gland disorders. The postnatal gonadotropic surge provides a useful period to explore the gonadotropic axis for assessing the presence of congenital hypogonadotropic hypogonadism (CHH).

AIM

To explore the functioning of the hypothalamic-pituitary-gonadal axis in the postnatal gonadotropic surge for an early diagnosis of CHH in newborns or infants suspected of having CPHD.

SUBJECTS AND METHODS

A cohort of 27 boys under 6 months and 19 girls under 24 months of age with suspected hypopituitarism was studied. Serum concentrations of LH, FSH, testosterone, inhibin B, anti-Müllerian hormone (AMH) and estradiol were measured, and male external genitalia were characterized as normal or abnormal (micropenis, microorchidism and/or cryptorchidism).

RESULTS

CPHD was confirmed in 36 out of 46 patients. Low LH and testosterone levels were found in 66% of the hypopituitary males, in significant association with the presence of abnormal external genitalia. This abnormality had a positive predictive value of 93% for CHH. No significant association was observed between serum FSH, AMH and inhibin B and the patient's external genitalia.

CONCLUSION

In newborn or infant boys with CPHD, LH and testosterone concentrations measured throughout the postnatal gonadotropic surge, together with a detailed evaluation of the external genital phenotype, facilitate the diagnosis of CHH at an early stage.

Insulin level and insulin sensitivity indices among healthy children and adolescents

INTRODUCTION

Information on insulin reference values and insulin sensitivity indices in the field of pediatrics is scarce.

OBJECTIVE

To describe insulin range and insulin sensitivity surrogate indices during childhood.

MATERIALS AND METHODS

Fasting insulin level range and surrogate indices, such as the homeostasis model assessment of insulin resistance (HOMA-IR), among healthy children and adolescents by age, body mass index, pubertal stage (PS), insulin-like growth factor-1 (IGF-1), total cholesterol, and triglycerides.

RESULTS

Two hundred and twenty-six healthy children and adolescents (1-18 years old) were included. Insulin increased with age, body mass index, pubertal stage, IGF-1 and triglyceride levels (r2= 0.38, p 〈 0.0001). Prepubertal children 〉 7.5 years old had higher insulin levels [median (P3 and P97) pIU/mL: 5.0 (1.7-9.6)] than prepubertal children 〈 7.5 years old [2.9 pIU/ mL (1.3-10.9), p 〈 0.01]. During puberty (from PS II to PS V), insulin was higher in girls than in boys [7.4 (1.8-16.9) versus 5.8 (1.8-12.9), p 〈 0.01]. The HOMA-IR index increased in the group of prepubertal children 〉 7.5 years old: 1.1 (0.32.0) versus children 〈 7.5 years old: 0.6 (0.3-1.4, p 〈 0.01). The insulin level and HOMA-IR results were higher in pubertal children compared to the prepubertal group (p 〈 0.001).

CONCLUSIONS

Known physiological changes were observed inboth insulin levels and the HOMA-IR index among children and adolescents. A fasting blood insulin level of 10 pIU/mL in prepubertal children and of 17 pIU/mL and 13 pIU/mL in pubertal girls and boys, respectively, may be considered as an acceptable cut-off value in healthy children. A HOMA-IR value 〉 2.0 and 〉 2.6 in prepubertal and pubertal children, respectively, may be considered a warning sign for pediatricians to further investigate insulin resistance.

Association of serum components of the GH-IGFs-IGFBPs system with GHR-exon 3 polymorphism in normal and idiopathic short stature children

OBJECTIVE

To investigate the possible association of circulating components of GH-IGFs-IGFBPs system with the GHR-exon 3 genotype in normal and idiopathic short stature (ISS) children.

DESIGN

Descriptive, cross-sectional study in normal and ISS children.

SUBJECTS AND METHODS

192 normal and 81 ISS children (age: 5-17 years) were included. Serum IGF-I, IGFBP3, ALS and GHBP levels were measured. GHR-exon 3 polymorphism (GHRd3) was analyzed by multiplex PCR assay. Normal and ISS children were divided according to GHR-exon 3 genotype: homozygous for the full-length GHR isoform (GHRfl) and carriers of one or two copies of the GHRd3 allele.

RESULTS

GHRd3 genotype distribution (fl:fl/fl:d3/d3:d3,%) in normal (60:34:6) and ISS (64:32:4) was similar and reached Hardy-Weinberg equilibrium. ISS children had significantly reduced levels of GHBP and GH-dependent factors as compared to controls (p<0.0001). Within the normal group, homozygous carriers of the GHRfl allele had significantly higher GHBP serum levels than those with one or two copies of the GHRd3 allele (Mean ± SEM; GHRfl: 3.2 ± 0.2 vs GHRd3: 2.7 ± 0.2 nmol/L, p = 0.04). No other significant association with GHR exon 3 polymorphism was found in either the normal or the ISS groups.

CONCLUSIONS

GHR exon 3 polymorphism is distributed similarly in normal and ISS children, however only normal homozygous children for GHRfl allele showed higher GHBP levels. The lack of association between GHBP and GHR polymorphism in ISS children might be related to the heterogeneity of this group, where potential defects in GH receptor action may result in partial GH insensitivity.

Type IA isolated growth hormone deficiency (IGHD) consistent with compound heterozygous deletions of 6.7 and 7.6 Kb at the GH1 gene locus

Isolated growth hormone deficiency (IGHD) may result from deletions/mutations in either GH1 or GHRHR genes. The objective of this study was to characterize the molecular defect in a girl presenting IGHD. The patient was born at 41 weeks of gestation from non-consanguineous parents. Clinical and biochemical evaluation included anthropometric measurements, evaluation of pituitary function, IGF-I and IGFBP-3 levels. Molecular characterization was performed by PCR amplification of GH1 gene and SmaI digestion of two homologous fragments flanking the gene, using genomic DNA from the patient and her parents as templates. At 1.8 years of age the patient presented severe growth retardation (height 61.2 cm, -7.4 SDS), truncal obesity, frontal bossing, doll face, and acromicria. MRI showed pituitary hypoplasia. Laboratory findings confirmed IGHD. GH1 gene could not be amplified in samples from the patient while her parents yielded one fragment of the expected size. SmaI digestion was consistent with the patient being compound heterozygous for 6.7 and 7.6 Kb deletions, while her parents appear to be heterozygous carriers for either the 6.7 or the 7.6 Kb deletions. We have characterized type IA IGHD caused by two different GH1 gene deletions, suggesting that this condition should be considered in severe IGHD, even in non-consanguineous families. Arq Bras Endocrinol Metab. 2012;56(8):558-63

Neonatal cholestasis in congenital pituitary hormone deficiency and isolated hypocortisolism: characterization of liver dysfunction and follow-up

INTRODUCTION

Neonatal cholestasis due to endocrine diseases is infrequent and poorly recognized. Referral to the pediatric endocrinologist is delayed.

OBJECTIVE

We characterized cholestasis in infants with congenital pituitary hormone deficiencies (CPHD), and its resolution after hormone replacement therapy (HRT).

SUBJECTS AND METHODS

Sixteen patients (12 males) were included; eleven with CPHD, and five with isolated central hypocortisolism.

RESULTS

Onset of cholestasis occurred at a median age of 18 days of life (range 2-120). Ten and nine patients had elevated transaminases and γGT, respectively. Referral to the endocrinologist occurred at 32 days (range 1 - 72). Remission of cholestasis occurred at a median age of 65 days, whereas liver enzymes occurred at 90 days. In our cohort isolated, hypocortisolism was a transient disorder.

CONCLUSION

Cholestasis due to hormonal deficiencies completely resolved upon introduction of HRT. Isolated hypocortisolism may be a transient cause of cholestasis that needs to be re-evaluated after remission of cholestasis.

[Diagnosis of congenital endocrinological disease in newborns with prolonged jaundice and hypoglycaemia]

INTRODUCTION

The association of prolonged neonatal jaundice and hypoglycaemia may be secondary to an endocrinological disease. Pituitary insufficiency and primary adrenal insufficiency are the most likely endocrine diseases that need to be ruled out.

MATERIAL AND METHODS

We retrospectively analysed the clinical and laboratory characteristics of thirteen patients referred to the Hospital de Niños Ricardo Gutiérrez between years 2003 and 2008 due to prolonged neonatal jaundice and hypoglycaemia secondary to pituitary insufficiency in twelve patients, and in one secondary to primary adrenal insufficiency.

RESULTS

All patients had a history of neonatal hypoglycaemia. Ten patients had conjugated hyperbilirubinaemia and six also had elevated transaminases. Combined pituitary hormone deficiency was observed in the twelve hypopituitarism patients. Hormonal replacement normalised liver function and resolved the prolonged jaundice in all the patients. None of them underwent liver biopsy. Hypoglycaemia also remitted after hormonal therapy.

CONCLUSIONS

Prolonged or cholestatic jaundice associated with neonatal hypoglycaemia is highly likely to be due to pituitary hormone deficiency or primary adrenal insufficiency. Early diagnosis and treatment of these children reverts the prolonged jaundice and prevents morbidity and mortality due to recurrent hypoglycaemia and hormone deficiencies.

Early onset of primary hypogonadism revealed by serum anti-Müllerian hormone determination during infancy and childhood in trisomy 21

Male patients with an extra sex chromosome or autosome are expected to present primary hypogonadism at puberty owing to meiotic germ-cell failure. Scarce information is available on trisomy 21, a frequent autosomal aneuploidy. Our objective was to assess whether trisomy 21 presents with pubertal-onset, germ-cell specific, primary hypogonadism in males, or whether the hypogonadism is established earlier and affects other testicular cell populations. We assessed the functional status of the pituitary-testicular axis, especially Sertoli cell function, in 117 boys with trisomy 21 (ages: 2months-20year). To compare with an adequate control population, we established reference levels for serum anti-Müllerian hormone (AMH) in 421 normal males, from birth to adulthood, using a recently developed ultrasensitive assay. In trisomy 21, AMH was lower than normal, indicating Sertoli cell dysfunction, from early infancy, independently of the existence of cryptorchidism. The overall prevalence rate of AMH below the 3rd percentile was 64.3% in infants with trisomy 21. Follicle-stimulating hormone was elevated in patients <6months and after pubertal onset. Testosterone was within the normal range, but luteinizing hormone was elevated in most patients <6months and after pubertal onset, indicating a mild Leydig cell dysfunction. We conclude that in trisomy 21, primary hypogonadism involves a combined dysfunction of Sertoli and Leydig cells, which can be observed independently of cryptorchidism soon after birth, thus prompting the search for new hypotheses to explain the pathophysiology of gonadal dysfunction in autosomal trisomy.

[Menstrual cycle disorders in adolescence]

The high prevalence of menstrual disorders during the first years after menarche is well recognized. This is usually a cause of concern for parents and patients, and a common reason for visiting the pediatrician. The immaturity of the hypothalamic-pituitary-ovarian axis is the major cause of these disorders, but there are also some general organic or emotional conditions that may alter the menstrual cycle, which is a sensitive indicator of health. Physiology of the menstrual cycle, its alterations, etiology, assessment, diagnosis and treatment are reviewed in this article.

Basal follicle-stimulating hormone and peak gonadotropin levels after gonadotropin-releasing hormone infusion show high diagnostic accuracy in boys with suspicion of hypogonadotropic hypogonadism

CONTEXT

Differential diagnosis between hypogonadotropic hypogonadism (HH) and constitutional delay of puberty in boys is challenging. Most tests use an acute GnRH stimulus, allowing only the release of previously synthesized gonadotropins. A constant GnRH infusion, inducing de novo gonadotropin synthesis, may allow a better discrimination.

OBJECTIVE

We evaluated the diagnostic accuracy of basal and peak gonadotropins after GnRH infusion, measured by ultrasensitive assays, to confirm the diagnosis in boys with suspected HH.

DESIGN AND SETTING

We conducted a validation study following Standards for Reporting of Diagnostic Accuracy criteria at a tertiary public hospital.

PATIENTS AND METHODS

A GnRH i.v. infusion test was performed in 32 boys. LH and FSH were determined by immunofluorometric assay at 0-120 min. DIAGNOSIS ASCERTAINMENT: The following diagnoses were ascertained: complete HH (n = 19; testes < 4 ml at 18 yr), partial HH (n = 6; testes enlargement remained arrested for > or = 1 yr or did not reach 15 ml), and constitutional delay of puberty (n = 7; testes > or = 15 ml at 18 yr).

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values, and diagnostic efficiency were assessed.

RESULTS

Basal FSH less than 1.2 IU/liter confirmed HH with specificity of 1.00 (95% confidence interval = 0.59-1.00), rendering GnRH infusion unnecessary. In patients with basal FSH of at least 1.2 IU/liter, the coexistence of peak FSH less than 4.6 IU/liter and peak LH less than 5.8 IU/liter after GnRH infusion had high specificity (1.00; 95% confidence interval = 0.59-1.00) and diagnostic efficiency (76.9%) for HH.

CONCLUSIONS

Basal FSH less than 1.2 IU/liter confirms HH, which precludes from further testing, reducing patient discomfort and healthcare system costs. In patients with basal FSH of at least 1.2 IU/liter, a GnRH infusion test has a high diagnostic efficiency.

[Growth hormone treatment in younger than six years of age short children born small for gestational age]

INTRODUCTION

Approximately 10% of children born small for gestational age (SGA) do not show spontaneous catch-up growth.

OBJECTIVE

Our objective was to assess the efficacy and safety of 2 years growth hormone treatment in children younger than 6 years of age, born SGA.

MATERIAL AND METHODS

Fourteen patients, mean age 4.2 + or - 1.1 years were treated with growth hormone at 1.0 UI/kg/wk for two years.

RESULTS

Growth velocity increased from a mean + or - SD of 5.4 + or - 1.7 cm/yr to 9.8 + or - 1.50 cm/yr and 7.6 + or - 1.5 cm/yr during the first year and second year, respectively (p 0.00058). Serum IGF-I and its binding protein BP3 increased significantly throughout treatment. Basal glucose and insulin levels increased significantly during treatment, p= 0.0006 and p= 0.036, respectively, without significant changes in postprandial glucose or insulin levels. A mild change in insulin sensitivity was observed along treatment.

CONCLUSION

Two years growth hormone treatment induced a significant growth acceleration in children born small for gestational age, allowing them to attain a normal height. No serious adverse events were reported.

Abnormal responses to TRH in children born small for gestational age that failed to catch up

BACKGROUND

Fifteen percent of small for gestational age (SGA) children remain short and undergo thyroid axis evaluations.

METHODS

We analyzed data on thyroid assessment of 58 SGA children. Five had primary autoimmune hypothyroidism. In the remaining 53 patients, TSH, free T4 (FT4), antithyroid antibodies and 90-min TRH test results were analyzed. Patients were grouped into G1 (n = 27; normal) and G2 (n = 26; abnormal) according to their response to the TRH test compared with 30 normal children.

RESULTS

No differences were found in chronological age, gestational age, or birth weight standard deviation score (SDS) between groups. G2 showed higher SDS BMI at consultation (p < 0.05). FT4 (ng/dl) levels were similar in all groups, while basal TSH levels were statistically different in G2 compared with G1 and controls. In 21 G2 patients treated with thyroxine, FT4 levels did not change, TSH normalized, BMI SDS and height remained unchanged.

CONCLUSION

These data suggest that in SGA short children thyroid abnormalities may occur. Some of them may be due to a different setting of the hypothalamic-hypophyseal-thyroid axis during intrauterine life. Intrauterine growth retardation may permanently influence endocrine systems by affecting their programming during development. Further follow-up is needed to confirm these findings and to assess their natural history and potential clinical impact.

SHOX haploinsufficiency and Leri-Weill dyschondrosteosis: prevalence and growth failure in relation to mutation, sex, and degree of wrist deformity

SHOX mutations causing haploinsufficiency were reported in Leri-Weill dyschondrosteosis (LWD), which is characterized by mesomelic short stature and Madelung deformity of the wrists. The aim of this study was to determine the prevalence of SHOX mutations in LWD and to investigate the degree of growth failure in relation to mutation, sex, age of menarche, and wrist deformity. We studied 20 families with 24 affected children (18 females) and nine affected parents (seven females). All patients presented with bilateral Madelung deformity and shortening of the limbs. Height, sitting height, parental height, birth length, age of menarche, and presence of minor abnormalities were recorded. The degree of Madelung deformity was estimated by analysis of left hand radiographs. Microsatellite typing of the SHOX locus was used for detection of SHOX deletions and PCR direct sequencing for the detection of SHOX point mutations. In 14 of 20 families (70%), SHOX mutations were detected, with seven deletions (four de novo) and seven point mutations (one de novo). The latter included five missense mutations of the SHOX homeodomain, one nonsense mutation (E102X) truncating the whole homeodomain, and one point mutation (X293R) causing a C-terminal elongation of SHOX. Median age of the affected children was 13.4 yr (range, 6.1-18.3), mean height sd score (SDS) (sd in parentheses) was -2.85 (1.04), and mean sitting height/height ratio SDS was +3.06 (1.09). Mean birth length SDS was -0.59 (1.26). Growth failure occurred before school age. Height change during a median follow-up of 7.4 yr (range, 2.3-11.3) was insignificant with a mean change in height SDS of -0.10 (0.52). Mean height SDS of affected parents was -2.70 (0.85) vs. -0.91 (1.10) in unaffected parents. Height loss due to LWD was estimated calculating delta height defined by actual height SDS minus target height SDS of the unaffected parent(s). In the children, mean delta height SDS was -2.16 (1.06), the loss being greater in girls at -2.30 (1.02) than in boys at -1.72 (1.09) (P = 0.32). In patients with SHOX deletions, it was -2.14 (1.15) vs. -1.67 (0.73) for the SHOX point mutation group (P = 0.38). Mean delta height SDS was -2.26 (0.68) for the girls with early menarche (<12 yr) vs. -2.08 (0.91) for the other postmenarcheal girls (P = 0.72). Height loss in patients with radiologically severe wrist deformities in comparison with those having milder radiological signs was -2.81 (1.01) vs. -1.70 (1.04) (P = 0.03). GH treatment in five children during a median duration of 3.4 yr (range, 1.5-9.8 yr) with a median dosage of 0.23 mg/kg.wk (range, 0.14-0.25) resulted in a mean height SDS gain of +0.82 (0.34). In conclusion, SHOX defects were the main cause of LWD. Growth failure occurred during the first years of life with a mean height loss of 2.16 SDS whereas pubertal growth may only be mildly or not affected. Children with a severe degree of wrist deformity were significantly shorter than those with mild deformities. No statistically significant effects of type of mutation, age of menarche, or sex on height were observed. The effect of GH therapy varied between individuals and needs to be examined in controlled studies.

Height velocity in Argentinean girls with Turner's syndrome

Height velocities from birth to maturity derived from 1,049 height increments measured over intervals 0.85-1.15 years were studied from a sample of 187 patients with Turner's syndrome (TS) diagnosed on the basis of karyotype. Length of follow up in each girl varied from 1.0 to 11.0 years. Cross-sectional analysis showed a relatively stable growth velocity during pubertal ages. However, longitudinal analysis of individual growth curves showed the existence of a small growth spurt in 37 out of 47 girls with available data during pubertal years. Mean peak height velocity (PHV) of this spurt was 5.7 cm/year, SD 1.34; mean age at PHV was 12.66 years, SD 1.70. Selected percentiles were calculated using the least mean squares (LMS) method. Results show that a small growth spurt in girls with TS may be more frequent than previously thought.

Psychosocial outcome in growth hormone deficient patients diagnosed during childhood

Social disabilities have been described in GHD patients. The aim of this study was to evaluate the social outcome of a group of adult hypopituitary patients diagnosed and treated during childhood. Seventy patients were interviewed at a mean age of 25.6 years (range 18-50 yr). They answered a semistructured questionnaire and the Beck Depression Inventory test. Patients were compared for academic achievement, marital status and employment with the nearest age sibling. We found high levels of school repeaters, school was often not completed, and around 50% were overprotected by teachers and teased by peers. 32% were unemployed, while 58% of those employed work with their families. 80% still live with their parents; only 16% are married and 9% have children. 44% had no dating experience and 52% had never had sexual intercourse. Depression was common, especially in hypogonadic subjects. Juvenilization was the most common complaint. We did not found differences in maximal educational achievements and levels of employment between patients and siblings, but significantly more married siblings were found. Depression, social isolation and dependent life style were found in GHD patients. Appropriate medical and psychological counseling should be included for patients and their families as part of treatment.

Final height in long-term primary hypothyroid children

OBJECTIVE

We studied retrospectively the statural growth and bone maturation of 32 children with primary hypothyroidism in order to relate their final heights to their chronological ages, height deficits and bone ages at the beginning of treatment. Patients were grouped according to age when treatment was started: Group 1 (G1) (n = 17): (15 girls, 1 boy) 3.09 +/- 0.8 yr; Group 2 (G2) (n = 9): (7 girls, 2 boys) 9.1 +/- 1.2 yr, and Group 3 (G3) (n = 6): (5 girls, 1 boy) 13.58 +/- 1.13 yr. At diagnosis G1 and G2 were prepubertal and G3 children were in puberty. In 10 patients of G1, 7 of G2 and 6 (all) of G3 final height was compared with target height.

RESULTS

(SDS) Initial height: G1: -3.74 +/- 1.2; G2: -3.94 +/- 1.32; G3 -3.65 +/- 1. Height at onset of puberty: G1: -1.06 +/- 1.1; G2: -2.5 +/- 1.4. Height menarche stage 5: G1: -0.63 +/- 1.1; G2: -1.76 +/- 1.2; G3: -2.6 +/- 1.7. Final height: (whole group) G1: -0.85 +/- 0.91; G2: -1.6 +/- 1.3; G3: -2 +/- 1.5. Final height G1 (n = 10): -1.05 +/- 0.89; G2 (n = 7) 1.2 +/- 1. Target height G1 (n = 10): -1.22 +/- 0.78; G2 (n = 7): -0.8 +/- 1.2; G3 (n = 6): -1.07 +/- 1.5. Initial bone age: G1: -4.9 +/- 0.85; G2: -7.2 +/- 2.6; G3: -4.5 +/- 1.9. Bone age (onset of puberty) G1: -0.26 +/- 1.74; G2: -2 +/- 1.7; Bone age (menarche) G1: 0.09 +/- 0.6; G2: -0.5 +/- 0.6; G3: -0.76 +/- 0.82.

CONCLUSION

G1 and G2, prepubertal at diagnosis, reached a normal adult height with respect to target height; G3 did not, the difference being statistically significant (p < 0.04). Puberty plays a decisive role in the incomplete catch-up growth of longstanding hypothyroid patients.

Growth of Argentinian girls with Turner syndrome

Growth data on 254 patients with Turner syndrome from Argentina-120 with XO karyotype and 134 with other chromosomal abnormalities-were analysed. Birth weight and height were significantly reduced. Ninety patients had received oestrogen treatment from a mean age of 14-0 years (SD 1.2) and 17 patients had spontaneous menarche. Patients who underwent spontaneous menarche had a small growth spurt. Final height was slightly higher (139.8 cm SD 5.6), though not significantly different from the mean adult height of the whole sample (137.9 cm SD 5.7). Mean adult height was 3.73 SD below mean of the normal local population. Mean height velocities from birth to maturity are very similar to those found in other samples. Distance standards were prepared by fitting a fifth-degree polynomial to the interpolated mean heights at each 0.5 year of age, and to the raw SD. Selected centiles were then calculated from the smoothed values. Differences between adult height in local Turner syndrome girls and local normal population are very similar to the same Turner-normal differences described in other communities. Standards presented here are useful for evaluating Turner syndrome patients from Argentina, and may also be used by those with similar growth pattern in their normal population.

Growth follow-up in 100 children with congenital hypothyroidism before and during treatment

In order to assess the influence of age at onset of treatment on subsequent growth, height, weight, head circumference (HC) and bone age as estimated by Greulich-Pyle and TW2-RUS methods, 100 children with congenital hypothyroidism (CH) were studied before and during adequate treatment up to 5 years of age. The patients were divided into five groups according to age at the start of treatment: Group 1: < 2 months (n = 26); Group 2: 2-3 months (n = 13); Group 3: 3-6 months (n = 21); Group 4: 6-12 months (n = 20); Group 5: 12-24 months (n = 20). Before treatment, groups 1 and 2 differed significantly from the others in height (p < 0.001). With hormone therapy, catch-up growth was observed in groups 3 to 5, but at age 5 years no differences were found between groups. In all groups, height at 5 years of age correlated significantly with children's midparental height (p < 0.002). Bone age was initially retarded in groups 3 to 5, but approximated the chronological age by age 5 years. Initially, HC was less affected than height and remained relatively larger up to age 5 years in all groups. These findings show that thyroid hormone replacement in CH as late as 24 months corrects the short stature and delayed bone age by age 5 years.