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Free access

Whole-exome sequencing gives additional benefits compared to candidate gene sequencing in the molecular diagnosis of children with growth hormone or IGF-1 insensitivity

Lucy Shapiro, Sumana Chatterjee, Dina G Ramadan, Kate M Davies, Martin O Savage, Louise A Metherell, and Helen L Storr

Background

GH insensitivity (GHI) is characterised by short stature, IGF-1 deficiency and normal/elevated serum GH. IGF-1 insensitivity results in pre- and post-natal growth failure with normal/high IGF-1 levels. The prevalence of genetic defects is unknown.

Objective

To identify the underlying genetic diagnoses in a paediatric cohort with GH or IGF-1 insensitivity using candidate gene (CGS) and whole-exome sequencing (WES) and assess factors associated with the discovery of a genetic defect.

Methods

We undertook a prospective study of 132 patients with short stature and suspected GH or IGF-1 insensitivity referred to our centre for genetic analysis. 107 (96 GHI, 88 probands; 11 IGF-1 insensitivity, 9 probands) underwent CGS. WES was performed in those with no defined genetic aetiology following CGS.

Results

A genetic diagnosis was discovered 38/107 (36%) patients (32% probands) by CGS. WES revealed 11 patients with genetic variants in genes known to cause short stature. A further 2 patients had hypomethylation in the H19/IGF2 region or mUPD7 consistent with Silver–Russell Syndrome (total with genetic diagnosis 51/107, 48% or 41/97, 42% probands). WES also identified homozygous putative variants in FANCA and PHKB in 2 patients. Low height SDS and consanguinity were highly predictive for identifying a genetic defect.

Conclusions

Comprehensive genetic testing confirms the genetic heterogeneity of GH/IGF-1 insensitivity and successfully identified the genetic aetiology in a significant proportion of cases. WES is rapid and may isolate genetic variants that have been missed by traditional clinically driven genetic testing. This emphasises the benefits of specialist diagnostic centres.

Free access

Clinical and genetic heterogeneity of HNF4A/HNF1A mutations in a multicentre paediatric cohort with hyperinsulinaemic hypoglycaemia

Sinéad M McGlacken-Byrne, Jasmina Kallefullah Mohammad, Niamh Conlon, Diliara Gubaeva, Julie Siersbæk, Anders Jørgen Schou, Huseyin Demirbilek, Antonia Dastamani, Jayne A L Houghton, Klaus Brusgaard, Maria Melikyan, Henrik Christesen, Sarah E Flanagan, Nuala P Murphy, and Pratik Shah

Objective

The phenotype mediated by HNF4A/HNF1A mutations is variable and includes diazoxide-responsive hyperinsulinaemic hypoglycaemia (HH) and maturity-onset diabetes of the young (MODY).

Design

We characterised an international multicentre paediatric cohort of patients with HNF4Aor HNF1Amutations presenting with HH over a 25-year period (1995–2020).

Methods

Clinical and genetic analysis data from five centres were obtained. Diazoxide responsiveness was defined as the ability to maintain normoglycaemia without intravenous glucose. Macrosomia was defined as a birth weight ≥90th centile. SPSS v.27.1 was used for data analysis.

Results

A total of 34 patients (70.6% female, n  = 24) with a mean age of 7.1 years (s.d. 6.4) were included. A total of 21 different heterozygous HNF4Amutations were identified in 29 patients (four novels). Four different previously described heterozygous HNF1A mutations were detected in five patients. Most (97.1%, n  = 33) developed hypoglycaemia by day 2 of life. The mean birth weight was 3.8 kg (s.d. 0.8), with most infants macrosomic (n = 21, 61.8%). Diazoxide was commenced in 28 patients (82.3%); all responded. HH resolved in 20 patients (58.8%) following a median of 0.9 years (interquartile range (IQR): 0.2–6.8). Nine patients (n = 9, 26.5%) had developmental delay. Two patients developed Fanconi syndrome (p.Arg63Trp, HNF4A) and four had other renal or hepatic findings. Five (14.7%) developed MODY at a median of 11.0 years (IQR: 9.0–13.9). Of patients with inherited mutations (n = 25, 73.5%), a family history of diabetes was present in 22 (88.0%).

Conclusions

We build on the knowledge of the natural history and pancreatic and extra-pancreatic phenotypes of HNF4A/HNF1Amutations and illustrate the heterogeneity of this condition.

Free access

The prevalence and characteristic features of cyclicity and variability in Cushing's disease

Krystallenia I Alexandraki, Gregory A Kaltsas, Andrea M Isidori, Scott A Akker, William M Drake, Shern L Chew, John P Monson, G Michael Besser, and Ashley B Grossman

Objective

Cyclical Cushing's syndrome may render the diagnosis and management of Cushing's disease difficult. The aim of the present study was to investigate the prevalence of cyclicity and variability in patients with Cushing's disease, and to identify putative distinctive features.

Design

Retrospective case-note study.

Methods

We analysed the case records of 201 patients with Cushing's disease in a retrospective case-note study. Cyclicity was considered as the presence of at least one cycle, defined as a clinical and/or biochemical hypercortisolaemic peak followed by clinical and biochemical remission, followed by a new clinical and/or biochemical hypercortisolaemic peak. The fluctuations of mean serum cortisol levels, as assessed by a 5-point cortisol day curve, defined the variability.

Results

Thirty (14.9%; 26 females) patients had evidence of cyclicity/variability. ‘Cycling’ patients were older but no difference in sex or paediatric distribution was revealed between ‘cycling’ and ‘non-cycling’ patients. The median number of cycles was two for each patient, and 4 years was the median intercyclic period. A trend to lower cure rate post-neurosurgery and lower adenoma identification was observed in ‘cycling’ compared with ‘non-cycling’ patients. In multivariate analysis, older patients, longer follow-up, female sex and no histological identification of the adenoma were associated with an increased risk of cyclic disease.

Conclusions

This large population study reveals that cyclicity/variability is not an infrequent phenomenon in patients with Cushing's disease, with a minimum prevalence of 15%. Physicians should be alert since it can lead to frequent problems in diagnosis and management, and no specific features can be used as markers.

Restricted access

Do insulin-like growth factor binding proteins (IGFBPs) modulate the IGF-I growth promoting and differentiating effects in human neuroblastoma cells?

Stefano Cianfarani, Daniela Germani, Paola Rossi, Anna Spagnoli, and Delio Mercanti

Cianfarani S, Germani D, Rossi P, Spagnoli A, Mercanti D. Do insulin-like growth factor binding proteins (IGFBPs) modulate the IGF-I growth promoting and differentiating effects in human neuroblastoma cells? Eur J Endocrinol 1996;135:716–23. ISSN 0804–4643

The insulin-like growth factors (IGFs) are known to stimulate both the proliferation and differentiation of neuroblastoma cells, but the role of the IGF binding proteins (IGFBPs) has not yet been established. In this study, human neuroblastoma SH-SY5Y cells have been treated with IGF-I and its potent analogue des (1–3) IGF-I alone or following preincubation with a differentiating agent such as 12-o-tetradecanoylphorbol-13-acetate (TPA). Cell proliferation and differentiation were evaluated. Conditioned medium was tested for the presence of IGFBPs by ligand blotting. The SH-SY5Y cell proliferation was maximally stimulated by des (1–3) IGF-I. The TPA-induced differentiation of SH-SY5Y, evaluated by assessment of cell morphology and GAP-43 expression as a biochemical marker of differentiation, was potentiated by nanomolar concentrations of des (1–3) IGF-I and, to a smaller extent, IGF-I. Conditioned medium showed the presence of a major IGFBP band with an approximate molecular weight of 32.5 kD and a very faint band of approximately 24 kD. The IGFBP immunoblotting results suggest that the predominant band might represent IGFBP-2. Our data represent a first demonstration of the presence of IGFBPs in conditioned medium of human neuroblastoma SH-SY5Y cells. The finding that the potent IGF-I analogue des (1–3) IGF-I with reduced affinity for IGFBPs induce major effects on cell growth and differentiation suggests that the IGFBPs may play an active role in the neuronal response to the proliferative and differentiative effects of IGF-I.

Stefano Cianfarani, Laboratory of Paediatric Endocrinology, Department of Paediatrics, "Tor Vergata" University, via di Tor Vergata 135, 00133 Rome, Italy

Free access

Longitudinal growth, sexual maturation and final height in patients with congenital hypothyroidism detected by neonatal screening

M Salerno, M Micillo, S Di Maio, D Capalbo, P Ferri, T Lettiero, and A Tenore

OBJECTIVE: To evaluate longitudinal growth, pubertal development and final height in patients with congenital hypothyroidism (CH) detected by a neonatal screening programme, and to identify factors potentially affecting growth outcome. PATIENTS: Fifty-five patients (41 females) detected by neonatal screening and followed longitudinally from the time of diagnosis and treatment (25+/-5 days) up to the age of 17+/-0.5 years were evaluated retrospectively. RESULTS: Pubertal development began and progressed normally in both males and females. In boys, a testicular volume of 4 ml was reached at 11.3+/-1.0 years. In girls breast enlargement (B2) occurred at a mean age of 10.3+/-1.2 years and the mean age of menarche was 12.5+/-1.2 years. The onset and the progression of puberty were independent of the aetiology, the severity of CH and the timing of the beginning of treatment. Girls treated with an initial amount of L-thyroxine (L-T4) greater than 8 microg/kg per day showed an earlier onset of puberty (B2 9.4+/-0.9 years; menarche 11.5+/-0.8 years) compared with girls treated with a lower initial dose of L-T4 (B2 10.5+/-1.2 years; menarche 12.6+/-1.2 years; P<0.02). However, both groups attained a similar final height (-0.1+/-1.0 SDS and 0.4+/-1.0 SDS, respectively), which in both cases was above the target height (P=0.03). All the patients in the study attained a mean final height (0.1+/-1.1 SDS) within the normal range for the reference population and above the target height (-0.9+/-0.9 SDS, P<0.0001). No significant relationship was found between final height and severity of CH at diagnosis, initial L-T4 dosage or aetiology of the defect. Patients with ectopic gland, thyroid aplasia or in situ gland attained a similar mean final height (0.1+/-1.1 SDS, 0.5+/-1.0 SDS and -0.5+/-1.0 SDS, respectively), which was in all cases greater than target height (-1.0+/-0.9, -0.6+/-0.8, -0.9+/-0.8 respectively; P<0.05). CONCLUSIONS: Our results suggest that conventional management of children with CH detected by neonatal screening leads to normal sexual development and normal adult height, and that the major factor determining height in these children is familial genetic growth potential.

Restricted access

URINARY TESTOSTERONE GLUCURONIDE AND SULPHATE IN NEWBORNS AND YOUNG INFANTS

H. Krawczynska, M. Zachmann, and A. Prader

ABSTRACT

Urinary testosterone glucuronide and sulphate was determined separately by gas chromatography in 39 newborns and young infants (34 males and 5 females). In all cases, testosterone sulphate was higher than glucuronide. Boys excreted more of both conjugates (sulphate 6.7, glucuronide 2.2 μg/24 h) than girls (1.1 and 0.7 μg/24 h, respectively). Boys older than 3 weeks had higher values than boys younger than 2 weeks. The levels correlated positively with chronological age, negatively with the gestational age and not at all with the bilirubin levels. It is concluded that testosterone is excreted preferentially as the sulphate in the newborn period and that the high sulphokinase activity in foetal and neonatal testes is more likely responsible for this phenomenon than an impaired glucuronizing capacity of the liver.

Free access

Pubertal androgenization and gonadal histology in two 46,XY adolescents with NR5A1 mutations and predominantly female phenotype at birth

M Cools, P Hoebeke, K P Wolffenbuttel, H Stoop, R Hersmus, M Barbaro, A Wedell, H Brüggenwirth, L H J Looijenga, and S L S Drop

Objective

Most patients with NR5A1 (SF-1) mutations and poor virilization at birth are sex-assigned female and receive early gonadectomy. Although studies in pituitary-specific Sf-1 knockout mice suggest hypogonadotropic hypogonadism, little is known about endocrine function at puberty and on germ cell tumor risk in patients with SF-1 mutations. This study reports on the natural course during puberty and on gonadal histology in two adolescents with SF-1 mutations and predominantly female phenotype at birth.

Design and methods

Clinical and hormonal data and histopathological studies are reported in one male and one female adolescent with, respectively, a nonsense mutation (c.9T>A, p.Tyr3X) and a deletion of the first two coding exons (NCBI36/hg18 Chr9:g.(126306276-126307705)_(126303229-126302828)del) of NR5A1, both predicted to fully disrupt gene function.

Results

LH and testosterone concentrations were in the normal male range, virilization was disproportionate to the neonatal phenotype. In the girl, gonadectomy at 13 years revealed incomplete spermatogenesis and bilateral precursor lesions of testicular carcinoma in situ. In the boy, at the age of 12, numerous germ cells without signs of malignancy were present in bilateral testicular biopsy specimen.

Conclusions

In SF-1 mutations, the neonatal phenotype poorly predicts virilization at puberty. Even in poorly virilized cases at birth, male gender assignment may allow spontaneous puberty without signs of hypogonadotropic hypogonadism, and possibly fertility. Patients with SF-1 mutations are at increased risk for malignant germ cell tumors. In case of preserved gonads, early orchidopexy and germ cell tumor screening is warranted. The finding of premalignant and/or malignant changes should prompt gonadectomy or possibly irradiation.

Restricted access

Long-term treatment with diazoxide in childhood hyperinsulinism

D. B. GRANT, D. B. DUNGER, and E. C. BURNS

Abstract

This paper reviews the outcome in 12 children with hyperinsulinaemic hypoglycaemia who first developed symptoms between the ages of 2 and 8 months and who were treated with diazoxide (5 - 20 mg/kg/day) for 2-13 years. Two cases required subtotal pancreatectomy at the ages of 5 and 10 years because of recurrent hypoglycaemia and one girl with severe retardation died at the age of 6 years while still on diazoxide therapy. Two patients aged 3.5 and 9 years are still on treatment and in 7 cases diazoxide was discontinued between the ages of 2.5 and 14 years, indicating that spontaneous remission can be expected in a high proportion of children with post-neonatal hyperinsulinaemic hypoglycaemia. Of the 9 children who started diazoxide within 3 months of the onset of symptoms, 5 are of normal intelligence and 4 are moderately retarded (IQs 63-71). In 3 children diazoxide was started 8 months to 3 years after the onset of symptoms; two are retarded (IQs 60-70) and the third was severely retarded and died aged 6 years.

Free access

Molecular genetic study in two patients with congenital hypoaldosteronism (types I and II) in relation to previously published hormonal studies

M Peter, K Bunger, SL Drop, and WG Sippell

We performed a molecular genetic study in two patients with congenital hypoaldosteronism. An original study of these patients was published in this Journal in 1982. Both index cases, a girl (patient 1) and a boy (patient 2). presented with salt-wasting and failure to thrive in the neonatal period. Parents of patient 1 were not related, whereas the parents of patient 2 were cousins. Endocrine studies had shown a defect in 18-oxidation of 18-OH-corticosterone in patient 1 and a defect in the 18-hydroxylation of corticosterone in patient 2. Plasma aldosterone was decreased in both patients, whereas 18-OH-corticosterone was elevated in patient 1 and decreased in patient 2. Plasma corticosterone and 11-deoxycorticosterone were elevated in both patients, whereas cortisol and its precursors were in the normal range. According to the nomenclature proposed by Ulick, the defects are termed corticosterone methyl oxidase (CMO) deficiency type II in patient 1, and type I in patient 2 respectively. Genetic defects in the gene CYP11B2 encoding aldosterone synthase have been described in a few cases. In patient 1, we identified only one heterozygous amino acid substitution (V386A) in exon 7, which has no deleterious effect on the enzyme activity. In patient 2 and his older brother, we identified a homozygous single base exchange (G to T) in codon 255 (GAG), causing a premature stop codon E255X (TAG). The mutant enzyme has lost the five terminal exons containing the haem binding site, and is thus a loss of function enzyme. This is only the second report of a patient with CMO deficiency type II without a mutation in the exons and exon-intron boundaries, whereas the biochemical phenotype of the two brothers with CMO deficiency type I can be explained by the patient's genotype.

Restricted access

The Evaluation of Testicular Endocrine Function Before and in Puberty

Milo Zachman

In recent years, it became evident that the hypothalamo-pituitary-gonadal axis is functioning in boys already between the neonatal period and the onset of puberty. With sensitive techniques, testosterone and gonadotropines have been detected in the plasma and urine of prepubertal boys. It is now believed that, during this period of life, the axis is active, but that either the feedback mechanisms are adjusted to a different level, the hypothalamic centers being more sensitive to androgens and keeping the testicular androgen production low, or that the gonads are more refractory to the effect of gonadotropins.

The androgen levels in biological fluids from normal prepubertal boys are extremely low. It is therefore impossible to distinguish the basal values of children with defective steroid production from those of normal children. Recently, several investigators have, however, shown that stimulation of the testicular interstitial cells is possible, if human chorionic gonadotropin is administered for several