Diagnosis and Incidence of Congenital Combined Pituitary Hormone Deficiency in Denmark-A National Observational Study

CONTEXT

Congenital combined pituitary hormone deficiency (cCPHD) is the loss of ≥2 pituitary hormones caused by congenital factors.

OBJECTIVE

We aimed to estimate the national incidence of cCPHD diagnosed before age 18 years and in subgroups.

METHODS

Patients with cCPHD were identified in the Danish National Patient Registry and Danish hospital registries in the period 1996-2020. Hospital files were reviewed and incidences calculated using background population data. Incidence was the main outcome measure.

RESULTS

We identified 128 patients with cCPHD; 88 (68.8%) were males. The median (range) age at diagnosis was 6.2 (0.01-19.0) years. The median (25th;75th percentile) number of hormone deficiencies at diagnosis was 3 (3; 4) at <1 year vs 2 (2; 2) at 1-17 years, P < .0001. Abnormal pituitary magnetic resonance imaging findings were seen in 70.3% (83/118). For those born in Denmark aged <18 years at diagnosis (n = 116/128) the estimated national incidence (95% CI) of cCPHD was 10.34 (7.79-13.72) per 100 000 births, with an annual incidence rate of 5.74 (4.33-7.62) per million. In subgroup analysis (diagnosis <1 vs 1-17 years), the incidence was highest in the 1-17 years subgroup, 7.97 (5.77-11.00) vs 1.98 (1.39-2.84) per 100 000 births, whereas the annual incidence rate was highest at <1 year, 19.8 (13.9-28.4) vs 4.69 (3.39-6.47) per million births.

CONCLUSION

cCPHD had the highest incidence rate and the most hormone deficiencies in those diagnosed at <1 year. The incidence was highest in the 1-17 years age group, underscoring the need for multiple pituitary hormone investigations throughout childhood and adolescence in children with only 1 hormone deficiency.

Management of Neonatal Isolated and Combined Growth Hormone Deficiency: Current Status

Congenital growth hormone deficiency (GHD) is a rare disease caused by disorders affecting the morphogenesis and function of the pituitary gland. It is sometimes found in isolation but is more frequently associated with multiple pituitary hormone deficiency. In some cases, GHD may have a genetic basis. The many clinical signs and symptoms include hypoglycaemia, neonatal cholestasis and micropenis. Diagnosis should be made by laboratory analyses of the growth hormone and other pituitary hormones, rather than by cranial imaging with magnetic resonance imaging. When diagnosis is confirmed, hormone replacement should be initiated. Early GH replacement therapy leads to more positive outcomes, including reduced hypoglycaemia, growth recovery, metabolic asset, and neurodevelopmental improvements.

Copy number variation in pituitary stalk interruption syndrome: A large case series of sporadic non-syndromic patients and literature review

Abnormal hypothalamic/posterior pituitary development appears to be a major determinant of pituitary stalk interruption syndrome (PSIS). The observation of familial cases and associated congenital abnormalities suggests a genetic basis. Single-gene mutations explain less than 5% of the cases, and whole exome sequencing has shown heterogeneous results. The present study aimed to assess copy number variation (CNV) using array-based comparative genomic hybridization (aCGH) in patients with non-syndromic PSIS and comprehensively review data from the literature on CNV analysis in congenital hypopituitarism (CH) patients. Twenty-one patients with sporadic CH from our outpatient clinics presented with ectopic posterior pituitary (EPP) and no central nervous system abnormalities on magnetic resonance image (MRI) or any other malformations on physical examination at presentation were enrolled in the study. aCGH using a whole-genome customized 400K oligonucleotide platform was performed in our patients. For the literature review, we searched for case reports of patients with CH and CNV detected by either karyotype or aCGH reported in PubMed up to November 2021. Thirty-five distinct rare CNVs were observed in 18 patients (86%) and two of them (6%) were classified as pathogenic: one deletion of 1.8 Mb in chromosome 17 (17q12) and one deletion of 15 Mb in chromosome 18 (18p11.32p11.21), each one in a distinct patient. In the literature review, 67 pathogenic CNVs were published in 83 patients with CH, including the present study. Most of these patients had EPP (78% out of the 45 evaluated by sellar MRI) and were syndromic (70%). The most frequently affected chromosomes were X, 18, 20 and 1. Our study has found that CNV can be a mechanism of genetic abnormality in non-syndromic patients with CH and EPP. In future studies, one or more genes in those CNVs, both pathogenic and variant of uncertain significance, may be considered as good candidate genes.

Slipped capital femoral epiphysis with hypopituitarism in adults: A case report and literature review

RATIONALE

Slipped capital femoral epiphysis (SCFE) is a common disease in pediatric orthopedics. Most research on SCFE has focused on high-risk groups or the whole population, and studies focusing on adult SCFE patients are rare. In the present study, we report the case of an adult patient with SCFE.

PATIENT CONCERN

A 37-year-old man presented to our clinic with persistent pain that was poorly localized to both hips, groin regions, and thighs for more than 1 year.

DIAGNOSES

A bilateral hip X-ray examination was performed, and the femoral epiphyses were found to be unfused on both sides. Low levels of growth hormone (GH), insulin-like growth factor-1 (IGF-1), triiodothyronine (T3), thyroxine (T4), follicle-stimulating hormone, luteinizing hormone, estradiol, and testosterone, and high levels of thyroid-stimulating hormone, prolactin, and cortisol.

INTERVENTIONS

Hormone-substitution therapies (levothyroxine sodium to treat hypothyroidism and testosterone enanthate to treat hypogonadism) were prescribed. Total hip arthroplasty was performed to treat femoral epiphysis slippage.

OUTCOMES

After 6 months of postoperative follow-up, the patient's gait improved significantly, and bilateral hip pain was relieved.

LESSONS

When treating adults with SCFE, clinicians must be alert to endocrine disorders. Comprehensive imaging evaluation is crucial for the accurate diagnosis and selection of an appropriate treatment.

Dysgenesis and Dysfunction of the Pancreas and Pituitary Due to FOXA2 Gene Defects

CONTEXT

Developmental disorders of the pituitary gland leading to congenital hypopituitarism can either be isolated or associated with extrapituitary abnormalities (syndromic hypopituitarism). A large number of syndromic hypopituitarism cases are linked to mutations in transcription factors. The forkhead box A2 (FOXA2) is a transcription factor that plays a key role in the central nervous system, foregut, and pancreatic development.

OBJECTIVE

This work aims to characterize 2 patients with syndromic hypopituitarism due to FOXA2 gene defects.

RESULTS

We report a novel heterozygous nonsense c.616C > T(p.Q206X) variant that leads to a truncated protein that lacks part of the DNA-binding domain of FOXA2, resulting in impaired transcriptional activation of the glucose transporter type 2 (GLUT2)-luciferase reporter. The patient is the sixth patient described in the literature with a FOXA2 mutation, and the first patient exhibiting pancreatic hypoplasia. We also report a second patient with a novel de novo 8.53 Mb deletion of 20p11.2 that encompasses FOXA2, who developed diabetes mellitus that responded to sulfonylurea treatment.

CONCLUSION

Our 2 cases broaden the molecular and clinical spectrum of FOXA2-related disease, reporting the first nonsense mutation and the first case of pancreatic dysgenesis.

Evidence That the Etiology of Congenital Hypopituitarism Has a Major Genetic Component but Is Infrequently Monogenic

Purpose

Congenital hypopituitarism usually occurs sporadically. In most patients, the etiology remains unknown.

Methods

We studied 13 children with sporadic congenital hypopituitarism. Children with non-endocrine, non-familial idiopathic short stature (NFSS) (n = 19) served as a control group. Exome sequencing was performed in probands and both unaffected parents. A burden testing approach was used to compare the number of candidate variants in the two groups.

Results

First, we assessed the frequency of rare, predicted-pathogenic variants in 42 genes previously reported to be associated with pituitary gland development. The average number of variants per individual was greater in probands with congenital hypopituitarism than those with NFSS (1.1 vs. 0.21, mean variants/proband, P = 0.03). The number of probands with at least 1 variant in a pituitary-associated gene was greater in congenital hypopituitarism than in NFSS (62% vs. 21%, P = 0.03). Second, we assessed the frequency of rare, predicted-pathogenic variants in the exome (to capture undiscovered causes) that were inherited in a fashion that could explain the sporadic occurrence of the proband's condition with a monogenic etiology (de novo mutation, autosomal recessive, or X-linked recessive) with complete penetrance. There were fewer monogenic candidates in the probands with congenital hypopituitarism than those with NFSS (1.3 vs. 2.5 candidate variants/proband, P = 0.024). We did not find any candidate variants (0 of 13 probands) in genes previously reported to explain the phenotype in congenital hypopituitarism, unlike NFSS (8 of 19 probands, P = 0.01).

Conclusion

Our findings provide evidence that the etiology of sporadic congenital hypopituitarism has a major genetic component but may be infrequently monogenic with full penetrance, suggesting a more complex etiology.

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.

Cognitive and Motor Outcome in Patients with Early-Detected Central Congenital Hypothyroidism Compared with Siblings

CONTEXT

Early treatment of primary congenital hypothyroidism (CH) prevents irreversible brain damage. Contrary to primary CH, outcome studies on central CH are scarce. Most patients with central CH have multiple pituitary hormone deficiencies (MPHD); these patients are also at risk for neonatal hypoglycemia.

OBJECTIVE

To assess cognitive and motor outcome in patients with early-treated central CH detected by the Dutch neonatal screening.

METHODS

In this cross-sectional study, primary outcome full-scale intelligence quotient (FSIQ) was measured in patients with MPHD and patients with isolated central CH born between January 1, 1995, and January 1, 2015, with siblings as controls. Secondary outcomes were intelligence test subscales and motor function. Linear mixed models were used to compare both patient groups and siblings, followed by post hoc tests in case of significant differences.

RESULTS

Eighty-seven patients (52 MPHD; 35 isolated central CH) and 52 siblings were included. Estimated marginal means for FSIQ were 90.7 (95% CI 86.4-95.0) in patients with MPHD and 98.2 (95% CI 93.0-103.5) in patients with isolated central CH. While patients with MPHD scored lower FSIQs than siblings (mean difference -7.9 points, 95% CI -13.4 to -2.5; P = .002), patients with isolated central CH did not. Processing speed was lower in both patient groups than in siblings (mean differences -10.5 and -10.3 points). Motor difficulties occurred significantly more often in patients (33%) versus siblings (5%; P = .004).

CONCLUSION

In early-treated central CH, FSIQ is comparable with siblings in patients with isolated central CH, while patients with MPHD have a significantly lower FSIQ. This may be explained by disease-specific consequences of MPHD, such as neonatal hypoglycemia and more severe hypothyroidism.

Clinical lessons learned in constitutional hypopituitarism from two decades of experience in a large international cohort

CONTEXT

The international GENHYPOPIT network collects phenotypical data and screens genetic causes of non-acquired hypopituitarism.

AIMS

To describe main phenotype patterns and their evolution through life.

DESIGN

Patients were screened according to their phenotype for coding sequence variations in 8 genes: HESX1, LHX3, LHX4, PROP1, POU1F1, TBX19, OTX2 and PROKR2.

RESULTS

Among 1213 patients (1143 index cases), the age of diagnosis of hypopituitarism was congenital (24%), in childhood (28%), at puberty (32%), in adulthood (7.2%) or not available (8.8%). Noteworthy, pituitary hormonal deficiencies kept on evolving during adulthood in 49 of patients. Growth Hormone deficiency (GHD) affected 85.8% of patients and was often the first diagnosed deficiency. AdrenoCorticoTropic Hormone deficiency rarely preceded GHD, but usually followed it by over 10 years. Pituitary Magnetic Resonance Imaging (MRI) abnormalities were common (79.7%), with 39.4% pituitary stalk interruption syndrome (PSIS). The most frequently associated extrapituitary malformations were ophthalmological abnormalities (16.1%). Prevalence of identified mutations was 7.3% of index cases (84/1143) and 29.5% in familial cases (n = 146). Genetic analysis in 449 patients without extrapituitary phenotype revealed 36 PROP1, 2 POU1F1 and 17 TBX19 mutations.

CONCLUSION

This large international cohort highlights atypical phenotypic presentation of constitutional hypopituitarism, such as post pubertal presentation or adult progression of hormonal deficiencies. These results justify long-term follow-up, and the need for systematic evaluation of associated abnormalities. Genetic defects were rarely identified, mainly PROP1 mutations in pure endocrine phenotypes.

The Molecular Basis of Congenital Hypopituitarism and Related Disorders

CONTEXT

Congenital hypopituitarism (CH) is characterized by the presence of deficiencies in one or more of the 6 anterior pituitary (AP) hormones secreted from the 5 different specialized cell types of the AP. During human embryogenesis, hypothalamo-pituitary (HP) development is controlled by a complex spatio-temporal genetic cascade of transcription factors and signaling molecules within the hypothalamus and Rathke's pouch, the primordium of the AP.

EVIDENCE ACQUISITION

This mini-review discusses the genes and pathways involved in HP development and how mutations of these give rise to CH. This may present in the neonatal period or later on in childhood and may be associated with craniofacial midline structural abnormalities such as cleft lip/palate, visual impairment due to eye abnormalities such as optic nerve hypoplasia (ONH) and microphthalmia or anophthalmia, or midline forebrain neuroradiological defects including agenesis of the septum pellucidum or corpus callosum or the more severe holoprosencephaly.

EVIDENCE SYNTHESIS

Mutations give rise to an array of highly variable disorders ranging in severity. There are many known causative genes in HP developmental pathways that are routinely screened in CH patients; however, over the last 5 years this list has rapidly increased due to the identification of variants in new genes and pathways of interest by next-generation sequencing.

CONCLUSION

The majority of patients with these disorders do not have an identified molecular basis, often making management challenging. This mini-review aims to guide clinicians in making a genetic diagnosis based on patient phenotype, which in turn may impact on clinical management.

Marked phenotypic variable expression among brothers with duplication of Xq27.1 involving the SOX3 gene

We describe four phenotypically different brothers who share the same microduplication of Xq27.1, which contains the SOX3 gene. SOX3 mutations have been associated with growth hormone deficiency, variable degrees of additional pituitary hormone deficiencies, and mental retardation. SOX3 also appears to play an important role in pharyngeal arch segmentation that gives rise to craniofacial structures. While these four brothers have inherited the same mutation, they manifest a spectrum of phenotypes, ranging from complete, multiple pituitary hormone deficiencies to no apparent pituitary hormone deficiency with or without craniopharyngeal/facial dysmorphisms. We look to the literature to provide putative explanations for the variable expression of the brothers' shared SOX3 mutation.

IGSF1 Deficiency Results in Human and Murine Somatotrope Neurosecretory Hyperfunction

CONTEXT

The X-linked immunoglobulin superfamily, member 1 (IGSF1), gene is highly expressed in the hypothalamus and in pituitary cells of the POU1F1 lineage. Human loss-of-function mutations in IGSF1 cause central hypothyroidism, hypoprolactinemia, and macroorchidism. Additionally, most affected adults exhibit higher than average IGF-1 levels and anecdotal reports describe acromegaloid features in older subjects. However, somatotrope function has not yet been formally evaluated in this condition.

OBJECTIVE

We aimed to evaluate the role of IGSF1 in human and murine somatotrope function.

PATIENTS, DESIGN, AND SETTING

We evaluated 21 adult males harboring hemizygous IGSF1 loss-of-function mutations for features of GH excess, in an academic clinical setting.

MAIN OUTCOME MEASURES

We compared biochemical and tissue markers of GH excess in patients and controls, including 24-hour GH profile studies in 7 patients. Parallel studies were undertaken in male Igsf1-deficient mice and wild-type littermates.

RESULTS

IGSF1-deficient adult male patients demonstrated acromegaloid facial features with increased head circumference as well as increased finger soft-tissue thickness. Median serum IGF-1 concentrations were elevated, and 24-hour GH profile studies confirmed 2- to 3-fold increased median basal, pulsatile, and total GH secretion. Male Igsf1-deficient mice also demonstrated features of GH excess with increased lean mass, organ size, and skeletal dimensions and elevated mean circulating IGF-1 and pituitary GH levels.

CONCLUSIONS

We demonstrate somatotrope neurosecretory hyperfunction in IGSF1-deficient humans and mice. These observations define a hitherto uncharacterized role for IGSF1 in somatotropes and indicate that patients with IGSF1 mutations should be evaluated for long-term consequences of increased GH exposure.

Genetic causes of hypopituitarism

Hypopituitarism in neonates is rare, but has life-threatening complications if untreated. This review describes the features of hypopituitarism and the evidence for which infants in whom a genetic cause should be suspected. Importantly, neonates are often asymptomatic or present with non-specific symptoms. Hypopituitarism can be due to abnormal gland development as a result of genetic defects, which result from mutations in gene coding for transcription factors which regulate pituitary development. The mutations can be divided into those causing isolated hypopituitarism or those causing syndromes with associated hypopituitarism. The latter involve mutations in transcription factors which regulate pituitary, as well as extra-pituitary development. There is a paucity of evidence as to which patients should be investigated for genetic mutations, but detailed clinical and biochemical phenotyping with magnetic resonance imaging of the pituitary gland could help target those in whom genetic investigations would be most appropriate.

Severe, persistent neonatal hypoglycemia as a presenting feature in patients with congenital hypopituitarism: a review of our case series

Background Persistent hypoglycemia (PH) beyond 3 days of life warrants investigation which includes a critical sample. We report our case series of five neonates who presented with PH as the first sign of congenital hypopituitarism. Design This is a case series. Methods/Results This is a case series of five neonates evaluated at our academic institution in a 3-year period (2013-2016), who presented with persistent severe hypoglycemia and were subsequently diagnosed with congenital hypopituitarism. All neonates were full term (mean gestational age 39.8 ± 1.4 weeks) born by caesarian section with a mean weight of 3.5 ± 0.16 kg and a mean length of 51.2 ± 1.2 cm at birth. All five neonates had PH beyond 3 days with an average blood glucose (BG) <35 mg/dL at presentation, requiring a mean glucose infusion rate (GIR) of 7.22 ± 1.98 mg/kg/min. The average BG during the critical sample was 42 ± 0.16 mg/dL (three patients). The mean duration of requirement of the glucose infusion was 6.2 ± 3 days during the immediate neonatal period. Diagnosis of the hypopituitarism took 2-52 days from the initial presentation of hypoglycemia. Besides growth hormone (GH) deficiency, cortisol deficiency was diagnosed in all the five neonates. Neuroimaging findings in all the neonates were consistent with pituitary stalk interruption syndrome (hypoplastic anterior pituitary, ectopic posterior pituitary [EPP] and interrupted pituitary stalk). Conclusions Hypoglycemia is a common metabolic complication affecting an infant in the immediate neonatal period. Delay in the diagnosis of hypopituitarism presenting as hypoglycemia is the result of the lack of awareness among neonatologists and/or pediatricians. We propose that providers be cognizant that PH can be the only presentation of hypopituitarism in the neonatal period. Therefore, having a high index of suspicion about this condition can avoid a delay in the evaluation, diagnosis and treatment of hypopituitarism.

Genetic diagnosis of congenital hypopituitarism by a target gene panel: novel pathogenic variants in GLI2, OTX2 and GHRHR

AIM

Congenital hypopituitarism has an incidence of 1:3500-10,000 births and is defined by the impaired production of pituitary hormones. Early diagnosis has an impact on management and genetic counselling. The clinical and genetic heterogeneity of hypopituitarism poses difficulties to select the order of genes to analyse. The objective of our study is to screen hypopituitarism genes (candidate and previously related genes) simultaneously using a target gene panel in patients with congenital hypopituitarism.

METHODS

Screening of 117 subjects with congenital hypopituitarism for pathogenic variants in 26 genes associated with congenital hypopituitarism by massively parallel sequencing using a customized target gene panel.

RESULTS

We found three novel pathogenic variants in OTX2 c.295C>T:p.Gln99*, GLI2 c.1681G>T:p.Glu561* and GHRHR c.820_821insC:p.Asp274Alafs*113, and the previously reported variants in GHRHR c.57+1G>A and PROP1 [c.301_302delAG];[c.109+1G>A].

CONCLUSIONS

Our results indicate that a custom-designed panel is an efficient method to screen simultaneously variants of biological and clinical relevance for congenital GH deficiency. A genetic diagnosis was possible in 5 out of 117 (4%) patients of our cohort. We identified three novel pathogenic variants in GHRHR, OTX2 and GLI2 expanding the spectrum of variants associated with congenital hypopituitarism.

Reduced Hepatocellular Expression of Canalicular Transport Proteins in Infants with Neonatal Cholestasis and Congenital Hypopituitarism

OBJECTIVE

To assess whether prolonged neonatal cholestasis, described in congenital hypopituitarism and septo-optic dysplasia (SOD), is associated with altered expression of selected canalicular ectoenzymes and canalicular transport proteins.

STUDY DESIGN

Children with congenital hypopituitarism (n = 21), SOD (n = 18), and cholestasis seen in our center over 26 years were reviewed. Histopathologic findings in archival liver biopsy specimens were assessed (n = 10) and in those with low/normal levels of serum γ-glutamyltransferase (GGT) activity despite conjugated hyperbilirubinemia, expression of canalicular ectoenzymes and canalicular transport proteins was evaluated immunohistochemically.

RESULTS

Patients presented at a median age of 8 weeks (range 3-20 weeks) with median total bilirubin 116 µmol/L (45-287 µmol/L), GGT 95 IU/L (25-707 UI/L), and serum cortisol 51 nmol/L (17-240 nmol/L). All but 3 had low free thyroxin (median 9.6 pmol/L [6.8-26.9]) with increased thyroid-stimulating hormone levels (median 5.95 mU/L [<0.1-9.24]). Liver histologic features included moderate-to-severe intralobular cholestasis with nonspecific hepatitis, giant-cell transformation of hepatocytes, and fibrosis. In all, immunohistochemical staining for canalicular ectoenzymes and canalicular transport proteins revealed a degree of reduced expression, associated with normal serum GGT values in 6 of the 10 patients, and another 6 nonbiopsied infants with cholestasis also had low/normal serum GGT activity. Sequencing of ABCB11 and ATP8B1 performed in 6 of the biopsied patients did not identify pathogenic mutations. Following replacement therapy, biochemical evidence of hepatobiliary injury resolved in all children within a median period of 6 months.

CONCLUSION

Hepatobiliary involvement in congenital hypopituitarism associated with SOD has a good prognosis, but its etiology remains uncertain. Immunohistochemical expression of canalicular transport proteins was reduced in available liver samples.

Next generation sequencing panel based on single molecule molecular inversion probes for detecting genetic variants in children with hypopituitarism

BACKGROUND

Congenital Hypopituitarism is caused by genetic and environmental factors. Over 30 genes have been implicated in isolated and/or combined pituitary hormone deficiency. The etiology remains unknown for up to 80% of the patients, but most cases have been analyzed by limited candidate gene screening. Mutations in the PROP1 gene are the most common known cause, and the frequency of mutations in this gene varies greatly by ethnicity. We designed a custom array to assess the frequency of mutations in known hypopituitarism genes and new candidates, using single molecule molecular inversion probes sequencing (smMIPS).

METHODS

We used this panel for the first systematic screening for causes of hypopituitarism in children. Molecular inversion probes were designed to capture 693 coding exons of 30 known genes and 37 candidate genes. We captured genomic DNA from 51 pediatric patients with CPHD (n = 43) or isolated GH deficiency (IGHD) (n = 8) and their parents and conducted next generation sequencing.

RESULTS

We obtained deep coverage over targeted regions and demonstrated accurate variant detection by comparison to whole-genome sequencing in a control individual. We found a dominant mutation GH1, p.R209H, in a three-generation pedigree with IGHD.

CONCLUSIONS

smMIPS is an efficient and inexpensive method to detect mutations in patients with hypopituitarism, drastically limiting the need for screening individual genes by Sanger sequencing.

A Case of Congenital Hypopituitarism Associated With a 1p31 Microdeletion: A Possible Role for LEPR and JAK1

Context:

Genetic defects affecting the expression and function of factors involved in pituitary development have been found to be associated with congenital hypopituitarism (CH). However, for most cases of CH, the etiology remains unknown.

Case Description:

We present an unusual case of an infant with CH, associated with septo-optic dysplasia with an absent anterior pituitary and an ectopic posterior pituitary gland, resulting from a de novo 8.04-Mb interstitial deletion of chromosome 1p31.1-1p31.3. The deleted region includes several genes that might be involved in pituitary development, including LEPR and JAK1.

Conclusions:

Haploinsufficiency of LEPR and/or JAK1 might be associated with CH. This finding suggests a role for LEPR-mediated glycoprotein 130 signaling in human pituitary development.

A patient with pseudohypoaldosteronism type II complicated by congenital hypopituitarism carrying a KLHL3 mutation

Pseudohypoaldosteronism type II (PHA II) is a renal tubular disease that causes hyperkalemia, hypertension, and metabolic acidosis. Mutations in four genes (WNK4, WNK1, KLHL3, and CUL3) are known to cause PHA II. We report a patient with PHA II carrying a KLHL3 mutation, who also had congenital hypopituitarism. The patient, a 3-yr-old boy, experienced loss of consciousness at age 10 mo. He exhibited growth failure, hypertension, hyperkalemia, and metabolic acidosis. We diagnosed him as having PHA II because he had low plasma renin activity with normal plasma aldosterone level and a low transtubular potassium gradient. Further investigations revealed defective secretion of GH and gonadotropins and anterior pituitary gland hypoplasia. Genetic analyses revealed a previously known heterozygous KLHL3 mutation (p.Leu387Pro), but no mutation was detected in 27 genes associated with congenital hypopituitarism. He was treated with sodium restriction and recombinant human GH, which normalized growth velocity. This is the first report of a molecularly confirmed patient with PHA II complicated by congenital hypopituitarism. We speculate that both GH deficiency and metabolic acidosis contributed to growth failure. Endocrinological investigations will help to individualize the treatment of patients with PHA II presenting with growth failure.

GPR101 Mutations are not a Frequent Cause of Congenital Isolated Growth Hormone Deficiency

Patients with Xq26.3 microduplication present with X-linked acrogigantism (X-LAG) syndrome, an early-childhood form of gigantism due to marked growth hormone (GH) hypersecretion from mixed GH-PRL adenomas and hyperplasia. The microduplication includes GPR101, which is upregulated in patients' tumor tissue. The GPR101 gene codes for an orphan G protein coupled receptor that is normally highly expressed in the hypothalamus. Our aim was to determine whether GPR101 loss of function mutations or deletions could be involved in patients with congenital isolated GH deficiency (GHD). Taking advantage of the cohort of patients from the GENHYPOPIT network, we studied 41 patients with unexplained isolated GHD. All patients had Sanger sequencing of the GPR101 gene and array comparative genome hybridization (aCGH) to look for deletions. Functional studies (cell culture with GH secretion measurements, cAMP response) were performed. One novel GPR101 variant, c.589 G>T (p.V197L), was seen in the heterozygous state in a patient with isolated GHD. In silico analysis suggested that this variant could be deleterious. Functional studies did not show any significant difference in comparison with wild type for GH secretion and cAMP response. No truncating, frameshift, or small insertion-deletion (indel) GPR101 mutations were seen in the 41 patients. No deletion or other copy number variation at chromosome Xq26.3 was found on aCGH. We found a novel GPR101 variant of unknown significance, in a patient with isolated GH deficiency. Our study did not identify GPR101 abnormalities as a frequent cause of GH deficiency.

Characterization of facial phenotypes of children with congenital hypopituitarism and their parents: a matched case-control study

Congenital Hypopituitarism (CH) has traditionally been associated with specific facial phenotypes subsumed under the term midface retrusion, based on cephalometric studies. In this study, we used a systematic anthropometric approach to facial morphology in 37 individuals with CH and their parents, primarily of French Canadian ancestry, and compared them to a control group of 78 French Canadian patients with well-controlled type 1 diabetes and their parents. We were able to demonstrate clear morphological differences, which were more prevalent in the affected group than in the control group. More specifically, we showed the presence of a shorter skull base width (P < 0.001) and reduced inner canthal distance (P = 0.006) in the CH face, as well as a relative underdevelopment of the mandible (P = 0.001). These findings were present in individuals of all ages, and were independent of the duration of growth hormone treatment (median treatment 90.8 months; range 7.2-175.8 months). In addition, skull base width was significantly reduced in both mothers and fathers of affected children compared to the parents of the controls (P < 0.001), despite comparable parental heights, supporting an underlying genetic etiology. Such extensive phenotypic studies have not been done in congenital hypopituitarism and will provide further opportunities for data mining.

Congenital pituitary hormone deficiencies: role of LHX3/LHX4 genes

LHX3 and LHX4 are LIM domain transcription factors involved in the early steps of pituitary organogenesis. They are necessary for the proper differentiation of Rathke's pouch that gives rise to the anterior pituitary lobe. Mutations of these transcription factors are involved in congenital hypopituitarism: to date, nine mutations of LHX3 have been reported, responsible for variable pituitary hormone deficiencies and extrapituitary manifestations, including limited neck rotation. By contrast, only five LHX4 mutations have been reported, responsible for variable hormone deficiencies, and pituitary/intracranial abnormalities. Future investigations will aim to better understand human pituitary organogenesis and to shed light on the interspecies differences in the roles of these transcription factors.