Pituitary stalk interruption syndrome is characterized by genetic heterogeneity

Severe neonatal cholestasis in HNF1β deficiency: a case report and literature review

Neonatal cholestasis can be caused by several conditions, with biliary atresia being the major cause. Genetic and endocrinological etiologies represent other possibilities, with most of them requiring a rapid diagnosis and a specific treatment. We describe a neonatal case of severe cholestasis with low gamma glutamyl transferase in a child presenting with multiple abnormalities, including pituitary stalk interruption syndrome and consequent hypopituitarism. The cholestasis was rapidly resolved with hormone therapy. Genetic analysis showed a de novo 17q chromosome deletion, including the HNF1β gene implicated in liver damage, and this was considered causative of the complex clinical phenotype. Our case highlights the relationship between congenital hypopituitarism and HNF1β gene deletion in 17q12 deletion syndrome as a severe neonatal cholestasis etiology, emphasizing the need to be especially vigilant in cases with associated hypoglycemia. Prompt endocrine evaluation and genetic testing are crucial in neonatal cholestasis to start targeted therapy and long-term monitoring, which could mitigate serious complications.

Functional study of three cases with novel TBX19 variants

PURPOSE

Congenital isolated adrenocorticotropic hormone deficiency (CIAD) is an autosomal recessive disorder. This study identifies novel TBX19 variants for CIAD patients, explores its possible effect mechanism at the structural, functional and protein levels, and guides clinicians better understand the condition.

METHODS

The clinical characteristics of three CIAD children were summarized. Multiple sequence alignment was performed and five algorithms, PROVEA, PolyPhen2, Mutation Taster, FATHMM, and I Mutant2.0, were used for the pathogenicity prediction. In addition, the three-dimensional protein structure of wild-type TBX19 was generated by Alphafold 3 and its variants were shown using PyMOL. Furthermore, immunoblotting analysis was applied to examine changes in the protein levels and the luciferase reporter assay was performed to further investigate the effects of TBX19 and its variants on pro-opiomelanocortin (POMC) transcriptional activity.

RESULTS

We describe three Chinese patients with CIAD caused by TBX19 variants. The TBX19 variant, c.856C>T (p.R286*) was classified as pathogenic according to ACMG, whereas the other four variants, c.377C>T (p.P126L), c.602A>T (p.E201V), c.401A>G (p.H134R) and c.299G>A (p.R100H) were predicted to be disease-causing. Variants lead to alter interactions, conformational changes in proteins or truncate protein. TBX19 and PITX1 cooperated, resulting in a strong synergistic activation effect on POMC transcriptional expression. A functional study showed that the variants in our study result in a significant suppression of POMC transcriptional activity compared to wild-type TBX19.

CONCLUSIONS

Our study identifies five TBX19 loss-of-function variants, two of which are novel and that provides new perspectives into the pathophysiological mechanism and expands the variant spectrum in IAD.

Protein-Variant-Phenotype Study of NBAS Using AlphaFold in the Aspect of SOPH Syndrome

NBAS gene variants cause phenotypically distinct and nonoverlapping conditions, SOPH syndrome and ILFS2. NBAS is a so-called "moonlighting" protein responsible for retrograde membrane trafficking and nonsense-mediated decay. However, its three-dimensional model and the nature of its possible interactions with other proteins have remained elusive. Here, we used AlphaFold to predict protein-protein interaction (PPI) sites and mapped them to NBAS pathogenic variants. We repeated in silico milestone studies of the NBAS protein to explain the multisystem phenotype of its variants, with particular emphasis on the SOPH variant (p.R1914H). We revealed the putative binding sites for the main interaction partners of NBAS and assessed the implications of these binding sites for the subdomain architecture of the NBAS protein. Using AlphaFold, we disclosed the far-reaching impact of NBAS variants on the development of each phenotypic trait in patients with NBAS-related pathologies.

Two Cases of Late Diagnosis Pituitary Stalk Interruption Syndrome and Literature Review

Background

Pituitary stalk interruption syndrome (PSIS) is a rare congenital condition that includes the triad of a thin pituitary stalk, an ectopic posterior pituitary gland, and an absent or hypoplastic anterior pituitary gland and is usually diagnosed in infancy. This report presents two cases of late diagnosis of PSIS and a literature review of the relevant cases. The objective is to update data on such an uncommon syndrome to avoid the consequences of pituitary dysfunction including short stature, impaired cognitive function, negative impact on bone health, adrenal crises and delayed puberty.

Case Report

In this paper, we report on two cases of late diagnosis of PSIS with a history of growth hormone deficiency. The first case is a 21-year-old female presenting with generalized fatigability, dizziness and delayed puberty, while the second case is a 19-year-old female presenting with secondary amenorrhea. The hormonal profile of the first patient revealed panhypopituitarism; the second case had growth hormone deficiency subsequently had secondary hypogonadism with intact thyroid and adrenal functions. The diagnosis of PSIS was confirmed by magnetic resonance imaging (MRI), and both cases were treated with hormone supplements. Progress was also tracked through planned follow-up sessions. To the best of our knowledge, this is the first case series of such late diagnosis PSIS from Saudi Arabia.

Conclusion

The key message of this paper is that rare etiologies such as PSIS should be kept in mind, especially for young patients presenting with clinical evidence of pituitary hormonal deficiencies, and MRI should be considered to confirm diagnosis. The early diagnosis, hormonal replacement, and long-term follow-up are crucial to reducing negative impacts of pituitary hormonal deficiencies.

Oligogenic analysis across broad phenotypes of 46,XY differences in sex development associated with NR5A1/SF-1 variants: findings from the international SF1next study

BACKGROUND

Oligogenic inheritance has been suggested as a possible mechanism to explain the broad phenotype observed in individuals with differences of sex development (DSD) harbouring NR5A1/SF-1 variants.

METHODS

We investigated genetic patterns of possible oligogenicity in a cohort of 30 individuals with NR5A1/SF-1 variants and 46,XY DSD recruited from the international SF1next study, using whole exome sequencing (WES) on family trios whenever available. WES data were analysed using a tailored filtering algorithm designed to identify rare variants in DSD and SF-1-related genes. Identified variants were subsequently tested using the Oligogenic Resource for Variant Analysis (ORVAL) bioinformatics platform for a possible combined pathogenicity with the individual NR5A1/SF-1 variant.

FINDINGS

In 73% (22/30) of the individuals with NR5A1/SF-1 related 46,XY DSD, we identified one to seven additional variants, predominantly in known DSD-related genes, that might contribute to the phenotype. We found identical variants in eight unrelated individuals with DSD in DSD-related genes (e.g., TBCE, FLNB, GLI3 and PDGFRA) and different variants in eight genes frequently associated with DSD (e.g., CDH23, FLNB, GLI2, KAT6B, MYO7A, PKD1, SPRY4 and ZFPM2) in 15 index cases. Our study also identified combinations with NR5A1/SF-1 variants and variants in novel candidate genes.

INTERPRETATION

These findings highlight the complex genetic landscape of DSD associated with NR5A1/SF-1, where in several cases, the use of advanced genetic testing and filtering with specific algorithms and machine learning tools revealed additional genetic hits that may contribute to the phenotype.

FUNDING

Swiss National Science Foundation and Boveri Foundation Zurich.

Newborn screening for central congenital hypothyroidism: past, present and future

Congenital hypothyroidism (CH) is defined as thyroid hormone deficiency at birth and constitutes one of the most common causes of preventable intellectual disability worldwide. Central CH is caused by insufficient pituitary or hypothalamic control of thyroid function, biochemically characterized by a low serum free thyroxine (fT4), in combination with a low, normal or mildly elevated thyroid-stimulating hormone (TSH). Central CH is less common than primary CH and is part of multiple pituitary hormone deficiencies (MPHD) in most of the cases. MPHD at birth, also known as 'congenital hypopituitarism', is a potentially life-threatening condition due to the possible co-occurrence of adrenocorticotropin hormone and growth hormone deficiency that can result in severe hypoglycemia and adrenal crisis. To date, central CH is the only pituitary hormone deficiency suitable for newborn screening (NBS), providing an opportunity for early detection of MPHD. Even though the first NBS programs utilized T4-based methods that were able to identify central CH, most countries have since transitioned to TSH-based approaches due to the high rate of false positives associated with T4-based strategies. Now, 50 years after the introduction of NBS for CH, only a few countries around the world have a screening program capable of detecting central CH. In this paper, we review the past, present and future of NBS for central CH. We will outline the importance of early detection of central CH and discuss the challenges and opportunities of screening for this condition.

Progress in investigating pituitary stalk lesions: A review

Pituitary stalk lesions are uncommon and are typically identified through pituitary magnetic resonance imaging and screening for causes of diabetes insipidus. Recent literature indicates that pituitary stalk lesions primarily manifest as pituitary stalk interruption syndrome and thickening of the pituitary stalk. The etiology of these lesions is complex and can be divided into major categories: congenital disorders, inflammatory or infectious diseases, and tumors. Therefore, achieving accurate diagnosis, differential diagnosis, and treatment for pituitary stalk lesions is crucial. This article aims to classify pituitary stalk lesions and delve into the latest research on their etiology, pathological mechanisms, clinical manifestations, diagnosis, and treatment of associated diseases.

Clinical and genetic features of childhood-onset congenital combined pituitary hormone deficiency: a retrospective, single-center cohort study

PURPOSE

To investigate the clinical characteristics and genetic features of childhood-onset congenital combined pituitary hormone deficiency (cCPHD) in Korean patients.

METHODS

We retrospectively analyzed 444 patients diagnosed with childhood-onset CPHD at a tertiary center between 1994 and 2021. After excluding acquired case, 43 patients with cCPHD were enrolled. Anthropometric measurements, hormone evaluations, brain magnetic resonance imaging (MRI), extrapituitary phenotypes, and adult outcomes were analyzed. Genetic analyses were performed on 26 patients using a targeted gene panel or whole exome sequencing.

RESULTS

Mean age at diagnosis was 3.2 years, and 41.9% were diagnosed at less than 1 year old. Short stature was the most frequent (37.2%) initial presentation, and mean height z-score was -2.4. More than half (n=23, 53.5%) of patients had neonatal features suggestive of hypopituitarism; however, only 15 (65.2%) were diagnosed in infancy. Growth hormone deficiency (GHD) was prevalent in 42 (97.7%), and 33 (76.7%) had 3 or more hormone deficiencies. Extrapituitary phenotypes were identified in 31 (72.1%). Brain MRI abnormalities correlated with a higher number of hormone deficiencies (P for trend 0.049) and were present in 33 patients (80.5%). Adult GHD was diagnosed in all 17 investigated patients, and metabolic disturbances were noted in 10 (58.9%). Pathogenic variants in POU1F1, GLI2, HESX1, TBC1D32, and ROBO1 were found in 5 (19.2%).

CONCLUSION

Considering the high proportion of neonatal presentations, identification of the early neonatal features of hypopituitarism to manage pituitary and extrapituitary phenotypes is critical. The genetic etiology of cCPHD warrants further exploration.

Exome Sequencing Has a High Diagnostic Rate in Sporadic Congenital Hypopituitarism and Reveals Novel Candidate Genes

CONTEXT

The pituitary gland is key for childhood growth, puberty, and metabolism. Pituitary dysfunction is associated with a spectrum of phenotypes, from mild to severe. Congenital hypopituitarism (CH) is the most commonly reported pediatric endocrine dysfunction, with an incidence of 1:4000, yet low rates of genetic diagnosis have been reported.

OBJECTIVE

We aimed to unveil the genetic etiology of CH in a large cohort of patients from Argentina.

METHODS

We performed whole exome sequencing of 137 unrelated cases of CH, the largest cohort examined with this method to date.

RESULTS

Of the 137 cases, 19.1% and 16% carried pathogenic or likely pathogenic variants in known and new genes, respectively, while 28.2% carried variants of uncertain significance. This high yield was achieved through the integration of broad gene panels (genes described in animal models and/or other disorders), an unbiased candidate gene screen with a new bioinformatics pipeline (including genes with high loss-of-function intolerance), and analysis of copy number variants. Three novel findings emerged. First, the most prevalent affected gene encodes the cell adhesion factor ROBO1. Affected children had a spectrum of phenotypes, consistent with a role beyond pituitary stalk interruption syndrome. Second, we found that CHD7 mutations also produce a phenotypic spectrum, not always associated with full CHARGE syndrome. Third, we add new evidence of pathogenicity in the genes PIBF1 and TBC1D32, and report 13 novel candidate genes associated with CH (eg, PTPN6, ARID5B).

CONCLUSION

Overall, these results provide an unprecedented insight into the diverse genetic etiology of hypopituitarism.

Fgf17: A regulator of the mid/hind brain boundary in mammals

The Fibroblast growth factor (FGFs) family consists of at least 22 members that exert their function by binding and activating fibroblast growth factor receptors (FGFRs). The Fgf8/FgfD subfamily member, Fgf17, is located on human chromosome 8p21.3 and mouse chromosome 14 D2. In humans, FGF17 can be alternatively spliced to produce two isoforms (FGF17a and b) whereas three isoforms are present in mice (Fgf17a, b, and c), however, only Fgf17a and Fgf17b produce functional proteins. Fgf17 is a secreted protein with a cleavable N-terminal signal peptide and contains two binding domains, namely a conserved core region and a heparin binding site. Fgf17 mRNA is expressed in a wide range of different tissues during development, including the rostral patterning centre, midbrain-hindbrain boundary, tailbud mesoderm, olfactory placode, mammary glands, and smooth muscle precursors of major arteries. Given its broad expression pattern during development, it is surprising that adult Fgf17-/- mice displayed a rather mild phenotype; such that mutants only exhibited morphological changes in the frontal cortex and mid/hind brain boundary and changes in certain social behaviours. In humans, FGF17 mutations are implicated in several diseases, including Congenital Hypogonadotropic Hypogonadism and Kallmann Syndrome. FGF17 mutations contribute to CHH/KS in 1.1% of affected individuals, often presenting in conjunction with mutations in other FGF pathway genes like FGFR1 and FLRT3. FGF17 mutations were also identified in patients diagnosed with Dandy-Walker malformation and Pituitary Stalk Interruption Syndrome, however, it remains unclear how FGF17 is implicated in these diseases. Altered FGF17 expression has been observed in several cancers, including prostate cancer, hematopoietic cancers (acute myeloid leukemia and acute lymphoblastic leukemia), glioblastomas, perineural invasion in cervical cancer, and renal cell carcinomas. Furthermore, FGF17 has demonstrated neuroprotective effects, particularly during ischemic stroke, and has been shown to improve cognitive function in ageing mice.

Ectopic Posterior Pituitary and Its Associations with Extrapituitary Intracranial Anomalies

Posterior pituitary ectopia is a very rare entity in the development of the pituitary gland. Several factors and multiple genes are associated with this entity causing both pituitary and extrapituitary abnormalities. Pituitary abnormalities can be various endocrine problems and extrapituitary abnormalities can be optic nerves and cerebellar hypoplasia, heterotopia, and abnormal vessels. This pictorial review represents the imaging manifestations of extrapituitary intracranial anomalies that can be associated with posterior pituitary ectopia.

Small pituitary volume and central nervous system anomalies in Fanconi Anemia

Introduction

Fanconi anemia (FA) is a genomic instability disorder associated with congenital abnormalities, including short stature and the presence of central nervous system anomalies, especially in the hypothalamic-pituitary area. Thus, differences in pituitary size could associate with the short stature observed in these patients. Our aim was to evaluate whether central nervous system abnormalities and pituitary gland volume correlate with height and hormone deficiencies in these patients.

Methods

In this cross-sectional exploratory study 21 patients diagnosed with FA between 2017 and 2022 in a Spanish Reference Center were investigated. Magnetic resonance imaging (MRI) was performed and pituitary volume calculated and corelated with height and other endocrine parameters.

Results

The percentage of abnormalities in our series was 81%, with a small pituitary (pituitary volume less than 1 SD) being the most frequent, followed by Chiari malformation type 1. The median value of pituitary volume was -1.03 SD (IQR: -1.56, -0.36). Short stature was found in 66.7% [CI95% 43-85.4]. Total volume (mm3) increases significantly with age and in pubertal stages. There were no differences between volume SD and pubertal stage, or the presence of endocrine deficiencies. No correlations were found between pituitary volume and the presence of short stature. The intraclass correlation index (ICC) average for volume was 0.85 [CI95% 0.61-0.94] indicating a good-to-excellent correlation of measurements.

Discussion

Central nervous system anomalies are part of the FA phenotype, the most frequent after pituitary hypoplasia being posterior fossa abnormalities, which may have clinical repercussions in the patient. It is therefore necessary to identify those who could be candidates for neurosurgical intervention. The size of the pituitary gland is smaller in these patients, but this does not seem to be related to hormone deficiency and short stature or exposure to a low dose of total body irradiation.

Trio-based whole exome sequencing in patients with ectopic posterior pituitary

Introduction

Ectopic posterior pituitary (EPP) is a rare congenital abnormality, sometimes associated with other midline defects, such as pituitary stalk interruption syndrome (PSIS), in which thin or absent pituitary stalk and anterior pituitary hypoplasia are combined to EPP. Most cases are sporadic, with few reports of familial cases, and many congenital hypopituitarism (CH) cases remain unsolved.

Objective

To search for candidate genes associated with this condition, we performed trio-based whole-exome sequencing (WES) on patients with EPP, including two familial cases.

Methods

This study included subjects with EPP and PSIS diagnosed by a simple MRI protocol (FAST1.2). We performed two distinct analyses in the trio-based WES. We looked for previously described genes associated with pituitary development. Next, we investigated the whole exome for variants inherited in a pattern consistent with a monogenic etiology.

Results

Ten families were evaluated; eight were composed of a child with EPP and healthy parents, one has two affected siblings, and one family has a son and mother with EPP. When analyzing the previously described candidate variants associated with pituitary development, we found variants in GLI2 and FGFR1 in three families. We also found six other variants of interest in three patients: KMT2A, GALR3, RTN4R, SEMA3A, NIPBL, and DSCAML1.

Conclusion

The analysis allowed us to find previously reported and not reported GLI2 variants, all inherited from healthy parents, which reinforces the incomplete penetrance pattern of GLI2 variants in the development of EPP and draws attention to possible future functional studies of those variants that have a recurrent expression in CH. We also found novel FGFR1 and SEMA3A variants that suggest an oligogenic mechanism in PSIS and EPP, as seen in patients with hypogonadotropic hypogonadism. We report the first case of a patient with Wiedemann-Steiner syndrome and PSIS, suggesting that the KMT2A gene may be related to pituitary development. Furthermore, the trios' analysis allowed us to find five other variants of interest. Future investigations may clarify the roles of these variants in the etiology of EPP and PSIS.

Pulsatile gonadotropin-releasing hormone therapy induces spermatogenesis in pituitary stalk interruption syndrome: A case report and review of the literature

BACKGROUND

Pituitary stalk interruption syndrome (PSIS) is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes. It is characterized by a deficiency in anterior pituitary hormones, such as growth hormone, gonadotropins, and thyroid hormones. Due to the syndrome's rarity and nonspecific manifestations, there is a lack of standardized treatment strategies. Consequently, early diagnosis through imaging and on-time intervention are crucial for improving patients' outcomes.

CASE SUMMARY

A 30-year-old man presented with absent secondary sexual characteristics and azoospermia. Laboratory evaluation revealed a deficiency in gonadotropins, while thyroid function was mostly within normal ranges. Magnetic resonance imaging of the pituitary gland showed pituitary stalk agenesis, hypoplasia of the anterior pituitary, and ectopic posterior pituitary, leading to the diagnosis of PSIS. Initially, the patient underwent 6 mo of gonadotropin therapy without significant changes in hormone levels and secondary sexual characteristics. Pulsatile gonadotropin-releasing hormone therapy was then administered, resulting in the detection of sperm in the semen analysis within 3 mo. After 6 mo, routine semen tests showed normal semen quality. The couple faced challenges in conceiving due to abstinence and underwent three cycles of artificial insemination, which was unsuccessful. They also attempted in vitro fertilization, but unfortunately, the woman experienced a miscarriage 10 wk after the embryo transfer.

CONCLUSION

Early detection, accurate diagnosis, and timely treatment are crucial in improving the quality of life and fertility of PSIS patients.

Lost Connection: A Case Report of Interrupted Pituitary Stalk Syndrome

Pituitary stalk interruption syndrome is a triad of thin (<1 mm) or complete absence of the pituitary stalk with either an aplastic or ectopic posterior lobe of the pituitary gland and a hypoplastic or absent anterior lobe of the pituitary. Patients present with growth retardation, short height, seizures, intellectual disability, and absence of sexual maturation at the expected time. Here, we presented a case of a 12-year-old male with stunted growth. Upon examination, there was reduced height, more than 3 standard deviations below the average for his chronological age. Laboratory results showed reduced levels of growth hormone and thyrotropin. Dual-energy X-ray absorptiometry revealed osteoporosis, while an X-ray of the wrist for bone age corresponded to seven years. MRI imaging confirmed the classical triad of findings for pituitary stalk interruption syndrome. Consequently, the patient was referred back to the endocrinology clinic for further management.

Re-analysis of gene mutations found in pituitary stalk interruption syndrome and a new hypothesis on the etiology

Background

Pituitary stalk interruption syndrome (PSIS) is a complex clinical syndrome characterized by varied pituitary hormone deficiencies, leading to severe manifestations across multiple systems. These include lifelong infertility, short stature, mental retardation, and potentially life-threatening pituitary crises if not promptly diagnosed and treated. Despite extensive research, the precise pathogenesis of PSIS remains unclear. Currently, there are two proposed theories regarding the pathogenic mechanisms: the genetic defect theory and the perinatal injury theory.

Methods

We systematically searched English databases (PubMed, Web of Science, Embase) and Chinese databases (CNKI, WanFang Med Online, Sinomed) up to February 24, 2023, to summarize studies on gene sequencing in PSIS patients. Enrichment analyses of reported mutated genes were subsequently performed using the Metascape platform.

Results

Our study included 37 articles. KEGG enrichment analysis revealed mutated genes were enriched in the Notch signaling pathway, Wnt signaling pathway, and Hedgehog signaling pathway. GO enrichment analysis demonstrated mutated genes were enriched in biological processes such as embryonic development, brain development, axon development and guidance, and development of other organs.

Conclusion

Based on our summary and analyses, we propose a new hypothesis: disruptions in normal embryonic development, partially stemming from the genetic background and/or specific gene mutations in individuals, may increase the likelihood of abnormal fetal deliveries, where different degrees of traction during delivery may lead to different levels of pituitary stalk interruption and posterior lobe ectopia. The clinical diversity observed in PSIS patients may result from a combination of genetic background, specific mutations, and variable degrees of traction during delivery.

Pituitary stalk interruption syndrome: A rare cause of amenorrhea in a patient with normal stature and secondary sexual characteristics

Pituitary stalk interruption syndrome (PSIS) is a rare disorder characterized by the imaging triad of thinned or absent pituitary stalk, ectopic posterior pituitary lobe, and hypoplastic or absent anterior lobe. Patients typically present with 1 or more anterior pituitary lobe hormone deficits, most commonly growth hormone or gonadotropin, but patients may achieve normal stature and secondary sexual characteristics. Here, we present a case of a young female patient presenting with amenorrhea, normal stature, and sexual development, and an imaging triad of PSIS. To our knowledge, this is the first case of PSIS to present with hyperprolactinemia and an otherwise normal pituitary hormone profile.

Exome sequencing in 16 patients with pituitary stalk interruption syndrome: A monocentric study

Pituitary stalk interruption syndrome (PSIS) is a rare disorder characterized by an absent or ectopic posterior pituitary, absent or interrupted pituitary stalk and anterior pituitary hypoplasia on magnetic resonance imaging (MRI), as well in some cases a range of heterogeneous somatic anomalies. The triad can be incomplete. Here, we performed exome sequencing on 16 sporadic patients, aged 0.4 to 13.7 years diagnosed with isolated or complex PSIS. Growth hormone deficiency was isolated in 10 cases, or associated with thyrotropin deficiency in 6 others (isolated (2 cases), associated with adrenocorticotropin deficiency (1 case), gonadotropins deficiency (1 case), or multiple deficiencies (2 cases)). Additional phenotypic anomalies were present in six cases (37.5%) including four with ophthalmic disorders. In 13 patients variants were identified that may contribute to the phenotype. However, only a single individual carried a variant classified as pathogenic. This child presented with the typical clinical presentation of Okur-Chung neurodevelopmental syndrome due to a CSNK2A1 missense variant. We also identified variants in the holoprosencephaly associated genes GLI2 and PTCH1. A likely pathogenic novel splice site variant in the GLI2 gene was observed in a child with PSIS and megacisterna magna. In the remaining 11 cases 26 variants in genes associated with pituitary development or function were identified and were classified of unknown significance. Compared with syndromic forms the diagnostic yield in the isolated forms of PSIS is low. Although we identified rare or novel missense variants in several hypogonadotropic hypogonadism genes (e.g. FGF17, HS6ST1, KISS1R, CHD7, IL17RD) definitively linking them to the PSIS phenotype is premature. A major challenge remains to identify pathogenic variants in cases with isolated PSIS.

Clinico-radiological correlation of pituitary stalk interruption syndrome in children with growth hormone deficiency

PURPOSE

To analyze the clinical, hormonal, and radiological characteristics of Pituitary stalk interruption syndrome (PSIS) in children with growth hormone deficiency (GHD).

METHODS

This is a prospective cross-sectional study, conducted over a period of three years in a short stature clinic of tertiary care referral hospital. 57 severe short stature children with proven GHD were included in the study.

RESULTS

Among 57 children with GHD, 14 (24%) were diagnosed as PSIS. The mean age at diagnosis was 11.8 ± 2.6years. The male to female ratio was 2.5:1. Nine (64%) children had multiple pituitary hormone deficiency (MPHD) and 5 (36%) had isolated growth hormone deficiency (IGHD). In spite of absent or ectopic posterior pituitary (EPP)in Magnetic Resonance Imaging (MRI) of PSIS cohorts, only one had Arginine vasopressin (AVP) deficiency. EPP was seen near median eminence in 6 (44%), elsewhere in 4 (28%), and absent in 4 (28%)children. The height gain following growth hormone therapy was better in PSIS cohorts as compared to non-PSIS.

CONCLUSION

Male gender, breech presentation, external congenital anomalies like cryptorchidism, midline defects and nystagmus were more common in children with PSIS. MPHD were more frequently seen in PSIS whereas IGHD in non-PSIS cohort. AVP deficiency is very rare in PSIS despite of absent or ectopic posterior pituitary in MRI. High index of clinical suspicion in all severe short stature may lead to early diagnosis and prompt initiation of growth hormone treatment for better outcome.

Imaging Features of Ectopic Tissues and Their Complications: Embryologic and Anatomic Approach

Ectopic tissue is an anatomic abnormality in which tissue develops in an area outside its normal location. It is primarily caused by abnormalities during the process of embryologic development. Although the majority of individuals with ectopic tissues remain asymptomatic, various symptoms and associated complications can occur. Failure in normal embryologic development leads to loss of normal physiologic function or may result in harmful functions such as ectopic hormonal secretion in the ectopic pituitary adenoma. Ectopic tissues may also frequently mimic tumors. For example, developmental abnormalities in the pharyngeal pouches may result in an ectopic parathyroid gland and ectopic thymus, both of which are frequently misdiagnosed as tumors. Adequate knowledge of embryology is essential for understanding the differential diagnoses of ectopic tissues and facilitating appropriate management. The authors summarize the embryologic development and pathogenesis of ectopic tissues by using illustrations to facilitate a deeper understanding of embryologic development and anatomy. Characteristic imaging findings (US, CT, MRI, and scintigraphy) are described for ectopic tissues of the brain, head, neck, thorax, abdomen, and pelvis by focusing on common conditions that radiologists may encounter in daily practice and their differential diagnoses. ^©RSNA, 2023 Quiz questions for this article are available through the Online Learning Center.

Obesity, Overweight, and Pituitary Stalk Interruption Syndrome in Children and Young Adults

CONTEXT

Pituitary stalk interruption syndrome (PSIS) is rare in the pediatric population. It combines ectopic posterior pituitary stalk interruption and anterior pituitary hypoplasia with hormonal deficiencies. The phenotype is highly heterogeneous and obesity/overweight seems to be underreported in the literature.

OBJECTIVE

To identify patients with PSIS and obesity or overweight, describe their phenotype, and compare them with patients with PSIS without overweight/obesity.

METHODS

Sixty-nine children and young adults with PSIS in a Toulouse cohort from 1984 to 2019 were studied. We identified 25 obese or overweight patients (OB-OW group), and 44 were nonobese/overweight (NO group). Then the groups were compared.

RESULTS

All cases were sporadic. The sex ratio was 1.6. The main reason for consultation in both groups was growth retardation (61% in OB-OW group, 77% in NO group). History of neonatal hypoglycemia was more common in the OB-OW than in the NO group (57% vs 14%, P = .0008), along with extrapituitary malformations (64% vs 20%, P < 0001). The incidence of caesarean section was higher in the OB-OW group (52%) than in the NO group (23%), although not significant (P = .07).

CONCLUSION

Patients with PSIS who are obese/overweight display interesting phenotypic differences that suggest hypothalamic defects. Studies are needed that include additional information on hormonal levels, particularly regarding oxytocin and ghrelin.

Panel testing for the molecular genetic diagnosis of congenital hypogonadotropic hypogonadism – a clinical perspective

Congenital hypogonadotropic hypogonadism (CHH) is a rare endocrine disorder that results in reproductive hormone deficiency and reduced potential for fertility in adult life. Discoveries of the genetic aetiology of CHH have advanced dramatically in the past 30 years, with currently over 40 genes recognised to cause or contribute to the development of this condition. The genetic complexity of CHH is further increased by the observation of di- and oligogenic, as well as classic monogenic, inheritance and incomplete penetrance. Very recently in the UK, a panel of 14 genes has been curated for the genetic diagnosis of CHH within the NHS Genomic Medicine Service programme. The aim of this review is to appraise the advantages and potential pitfalls of the use of a CHH panel in clinical endocrine diagnostics, and to consider the future avenues for developing this panel including the potential of whole exome or whole genome sequencing data analysis in this condition.

Delayed Diagnosis of Congenital Combined Pituitary Hormone Deficiency including Severe Growth Hormone Deficiency in Children with Persistent Neonatal Hypoglycemia—Case Reports and Review

Apart from stimulation of human growth and cell proliferation, growth hormone (GH) has pleiotropic metabolic effects in all periods of life. Severe GH deficiency is a common component of combined pituitary hormone deficiency (CPHD). CPHD may be caused by mutations in the genes encoding transcription factors and signaling molecules involved in normal pituitary development; however, often its genetic cause remains unknown. Symptoms depend on which hormone is deficient. The first symptom of GH or adrenocorticotropic hormone (ACTH) deficiency may be persistent hypoglycemia in apparently healthy newborns, which is often neglected. Diagnosing CPHD is based on decreased concentrations of hormones secreted by the anterior pituitary and peripheral endocrine glands. Findings in magnetic resonance imaging vary widely, including anterior pituitary hypoplasia/aplasia or pituitary stalk interruption syndrome (PSIS). Delayed diagnosis and treatment can be life-threatening. GH therapy is necessary to recover hypoglycemia and to improve auxological and psychomotor development. We present two girls, diagnosed and treated in our departments, in whom the diagnosis of CPHD was delayed, despite persistent neonatal hypoglycemia; and a review of similar cases, with attention paid to progress in the genetic assessments of such patients, since the introduction of whole exome sequencing that is especially important for PSIS.

Novel Genomic Variants, Atypical Phenotypes and Evidence of a Digenic/Oligogenic Contribution to Disorders/Differences of Sex Development in a Large North African Cohort

In a majority of individuals with disorders/differences of sex development (DSD) a genetic etiology is often elusive. However, new genes causing DSD are routinely reported and using the unbiased genomic approaches, such as whole exome sequencing (WES) should result in an increased diagnostic yield. Here, we performed WES on a large cohort of 125 individuals all of Algerian origin, who presented with a wide range of DSD phenotypes. The study excluded individuals with congenital adrenal hypoplasia (CAH) or chromosomal DSD. Parental consanguinity was reported in 36% of individuals. The genetic etiology was established in 49.6% (62/125) individuals of the total cohort, which includes 42.2% (35/83) of 46, XY non-syndromic DSD and 69.2% (27/39) of 46, XY syndromic DSD. No pathogenic variants were identified in the 46, XX DSD cases (0/3). Variants in the AR, HSD17B3, NR5A1 and SRD5A2 genes were the most common causes of DSD. Other variants were identified in genes associated with congenital hypogonadotropic hypogonadism (CHH), including the CHD7 and PROKR2. Previously unreported pathogenic/likely pathogenic variants (n = 30) involving 25 different genes were identified in 22.4% of the cohort. Remarkably 11.5% of the 46, XY DSD group carried variants classified as pathogenic/likely pathogenic variant in more than one gene known to cause DSD. The data indicates that variants in PLXNA3, a candidate CHH gene, is unlikely to be involved in CHH. The data also suggest that NR2F2 variants may cause 46, XY DSD.

Pituitary stalk interruption syndrome (PSIS): do not miss this diagnosis

Background

Pituitary stalk interruption syndrome (PSIS) is one of the rare endocrinal aetiologies of the abnormal short stature. This is a syndrome characterized by a specific tirade, an absent or hypoplastic anterior pituitary gland, thin or absent infundibulum, and ectopic posterior pituitary location. This type of pituitary dwarfism is usually presented in the first decade of life and may be first isolated with normal other pituitary hormones.

Results

Only 3 out of 117 dwarf patients (2.5%) were found to have pituitary stalk interruption syndrome.

Conclusion

Although of rare incidence, pituitary stalk interruption syndrome (PSIS) is an entity which leads to pituitary dwarfism and should be kept in mind while investigating a child with pituitary dwarfism and radiologists should be aware of its rarely encountered diagnostic MRI findings for early diagnosis and treatment.

Whole exome sequencing in patients with ectopic posterior pituitary

Context

Ectopic posterior pituitary (EPP), a condition in which the posterior pituitary gland is displaced due to defective neuronal migration, is frequently associated with hypopituitarism. Genetic variants play a role, but many cases remain unexplained.

Objective

A large EPP cohort was studied to explore the importance of genetic variants and how they correlate with clinical findings.

Methods

Whole exome sequencing was performed on a discovery sample of 27 cases to identify rare variants. The variants that met the criteria for rarity and biological relevance, or that were previously associated with EPP (ROBO1 and HESX1), were then resequenced in the 27 cases plus a replication sample of 51 cases.

Results

We identified 16 different variants in 12 genes in 15 of the 78 cases (19.2%). Complete anterior pituitary deficiency was twice as common in cases with variants of interest compared to cases without variants (9/15; 60% vs. 19/63; 30.1%, respectively; Z test; p=0.06). Breech presentation was more frequent in the variant positive group (5/15 vs. 1/63; Z test; p= 0.003). Four cases had variants in ROBO1 and one in HESX1, genes previously associated with EPP. The ROBO1 p.S18* variant has not been reported previously; ROBO1 p.Q1227H has not been associated with EPP previously.

Conclusions

EPP cases with variants of interest identified in this study were more likely to present with severe clinical disease. Several variants were identified in genes not previously associated with EPP. Our findings confirm that EPP is a multigenic disorder. Future studies are needed to identify additional genes.

Pituitary stalk interruption syndrome: phenotype, predictors, and pathophysiology of perinatal events

PURPOSE

There is limited data regarding Pituitary Stalk Interruption Syndrome (PSIS) from India. Moreover, the pathophysiological link between perinatal events and PSIS is unclear. We aim to elucidate the predictors of PSIS among patients with growth hormone deficiency (GHD) and perinatal events in PSIS by comparing cohorts of PSIS and genetically proven GHD without PSIS.

METHODS

Among 179 GHD patients, 56 PSIS and 70 genetically positive GHD (52-GHRHR, 15-POU1F1, and 3-PROP1) patients were included. Perinatal events, clinical anomalies, pituitary hormone deficiency, and imaging findings were recorded. We compared PSIS-isolated GHD (PSIS-IGHD) subgroup with GHRHR-IGHD and PSIS-combined pituitary hormone deficiency (PSIS-CPHD) subgroup with POU1F1/PROP1-CPHD.

RESULTS

PSIS patients (45 males, median age: 12.5 years) most commonly presented with short stature. At last follow-up (median age: 17.35 years), gonadal (during pubertal-age), thyroid and cortisol axes were affected in 81.6%, 62.5%, and 62.5%. 10/13 (77%) of PSIS children with initial IGHD diagnosis manifested hypogonadism during pubertal age. Male predominance, sporadic presentation, and clinical anomalies were significantly higher in both PSIS subgroups than in the respective genetic subgroups. Breech presentation was higher in PSIS-CPHD than POU1F1/PROP1-CPHD (44.4% vs 5.5%, p = 0.004). Neonatal hypoglycemia (22% vs. 0%, p = 0.05) and jaundice (42 vs. 5%, p = 0.004) were higher in PSIS-CPHD than PSIS-IGHD.

CONCLUSION

Later age at presentation and frequent hypogonadism were observed in our PSIS cohort. Male sex, sporadic presentation, clinical anomalies, and breech presentation predicted PSIS at presentation. Breech presentation in PSIS is likely due to stalk interruption rather than hormonal deficiency.

Whole Exome Sequencing Points towards a Multi-Gene Synergistic Action in the Pathogenesis of Congenital Combined Pituitary Hormone Deficiency

Combined pituitary hormone deficiency (CPHD) is characterized by deficiency of growth hormone and at least one other pituitary hormone. Pathogenic variants in more than 30 genes expressed during the development of the head, hypothalamus, and/or pituitary have been identified so far to cause genetic forms of CPHD. However, the etiology of around 85% of the cases remains unknown. The aim of this study was to unveil the genetic etiology of CPHD due to congenital hypopituitarism employing whole exome sequencing (WES) in two newborn patients, initially tested and found to be negative for PROP1, LHX3, LHX4 and HESX1 pathogenic variants by Sanger sequencing and for copy number variations by MLPA. In this study, the application of WES in these CPHD newborns revealed the presence of three different heterozygous gene variants in each patient. Specifically in patient 1, the variants BMP4; p.Ala42Pro, GNRH1; p.Arg73Ter and SRA1; p.Gln32Glu, and in patient 2, the SOX9; p.Val95Ile, HS6ST1; p.Arg306Gln, and IL17RD; p.Pro566Ser were identified as candidate gene variants. These findings further support the hypothesis that CPHD constitutes an oligogenic rather than a monogenic disease and that there is a genetic overlap between CPHD and congenital hypogonadotropic hypogonadism.

Exome sequencing of families from Ghana reveals known and candidate hearing impairment genes

We investigated hearing impairment (HI) in 51 families from Ghana with at least two affected members that were negative for GJB2 pathogenic variants. DNA samples from 184 family members underwent whole-exome sequencing (WES). Variants were found in 14 known non-syndromic HI (NSHI) genes [26/51 (51.0%) families], five genes that can underlie either syndromic HI or NSHI [13/51 (25.5%)], and one syndromic HI gene [1/51 (2.0%)]. Variants in CDH23 and MYO15A contributed the most to HI [31.4% (16/51 families)]. For DSPP, an autosomal recessive mode of inheritance was detected. Post-lingual expression was observed for a family segregating a MARVELD2 variant. To our knowledge, seven novel candidate HI genes were identified (13.7%), with six associated with NSHI (INPP4B, CCDC141, MYO19, DNAH11, POTEI, and SOX9); and one (PAX8) with Waardenburg syndrome. MYO19 and DNAH11 were replicated in unrelated Ghanaian probands. Six of the novel genes were expressed in mouse inner ear. It is known that Pax8-/- mice do not respond to sound, and depletion of Sox9 resulted in defective vestibular structures and abnormal utricle development. Most variants (48/60; 80.0%) have not previously been associated with HI. Identifying seven candidate genes in this study emphasizes the potential of novel HI genes discovery in Africa.

Truncating and zinc-finger variants in GLI2 are associated with hypopituitarism

Variants in transcription factor GLI2 have been associated with hypopituitarism and structural brain abnormalities, occasionally including holoprosencephaly (HPE). Substantial phenotypic variability and nonpenetrance have been described, posing difficulties in the counseling of affected families. We present three individuals with novel likely pathogenic GLI2 variants, two with truncating and one with a de novo missense variant p.(Ser548Leu), and review the literature for comprehensive phenotypic descriptions of individuals with confirmed pathogenic (a) intragenic GLI2 variants and (b) chromosome 2q14.2 deletions encompassing only GLI2. We show that most of the 31 missense variants previously reported as pathogenic are likely benign or, at most, low-risk variants. Four Zn-finger variants: p.(Arg479Gly), p.(Arg516Pro), p.(Gly518Lys), and p.(Tyr575His) were classified as likely pathogenic, and three other variants as possibly pathogenic: p.(Pro253Ser), p.(Ala593Val), and p.(Pro1243Leu). We analyze the phenotypic descriptions of 60 individuals with pathogenic GLI2 variants and evidence a morbidity spectrum that includes hypopituitarism (58%), HPE (6%) or other brain structure abnormalities (15%), orofacial clefting (17%) and dysmorphic facial features (35%). We establish that truncating and Zn-finger variants in GLI2 are associated with a high risk of hypopituitarism, and that a solitary median maxillary central incisor is part of the GLI2-related phenotypic variability. The most prevalent phenotypic feature is post-axial polydactyly (65%) which is also the mildest phenotypic expression of the condition, reported in many parents of individuals with systemic findings. Our approach clarifies clinical risks and the important messages to discuss in counseling for a pathogenic GLI2 variant.

Clinical, radiological, and molecular diagnosis of congenital pituitary diseases causing short stature

Short stature in children can be caused by congenital pituitary disorders involving at least one form of growth hormone deficiency. Clinical and radiological evaluations of the index case and family history assessments are essential to guide genetic diagnostic testing and interpret results. The first-line approach is panel testing of genes involved in pituitary development with variants known to be pathogenic in this context. It identifies a genetic cause in less than 10% of cases, however. Whole-exome and whole-genome sequencing techniques may provide original information but also raise new questions regarding the pathophysiological role of identified variants. These new tools can make genetic counselling more complex. The role of clinicians in these interpretations is therefore important. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

CDON gene contributes to pituitary stalk interruption syndrome associated with unilateral facial and abducens nerve palsy

The relationship between congenital defects of the brain and facial anomalies was proven. The Hedgehog signaling pathway plays a fundamental role in normal craniofacial development in humans. Mutations in the sonic hedgehog (SHH) signaling gene CDON have been recently reported in patients with holoprosencephaly and with pituitary stalk interruption syndrome (PSIS). This study’s aim was an elucidation of an 18-year-old patient presenting PSIS, multiple pituitary hormone deficiency, and congenital unilateral facial and abducens nerve palsy. Additionally, bilateral sensorineural hearing loss, dominating at the right site, was diagnosed. From the second year of life, growth deceleration was observed, and from the age of eight, anterior pituitary hormone deficiencies were gradually confirmed and substituted. At the MRI, characteristic triad for PSIS (anterior pituitary hypoplasia, interrupted pituitary stalk and ectopic posterior lobe) was diagnosed. We performed a comprehensive genomic screening, including microarrays for structural rearrangements and whole-exome sequencing for a monogenic defect. A novel heterozygous missense variant in the CDON gene (c.1814G > T; p.Gly605Val) was identified. The variant was inherited from the mother, who, besides short stature, did not show any disease symptoms. The variant was absent in control databases and 100 healthy subjects originating from the same population. We report a novel variant in the CDON gene associated with PSIS and congenital cranial nerve palsy. The variant revealed autosomal dominant inheritance with incomplete penetrance in concordance with previous studies reporting CDON defects.

Clinical evaluation of 31 children with pituitary insufficiency in the course of the pituitary stalk interruption syndrome. The unexpected growth without growth hormone in 2 children

INTRODUCTION

The pituitary stalk interruption syndrome (PSIS) is one of the complex -forms of congenital pituitary insufficiency. Symptoms resulting from insufficiency of the pituitary gland, in spite of the inborn character of the disease, may appear at various stages of life. The aim of this paper was to present clinical presentation in 31 patients with PSIS confirmed radiologically.

RESULTS

In the whole study population during first examination 25.8% children were diagnosed with combined pituitary hormone deficiency (CPHD). During the endocrinological observation (median follow-up 5.1 years, range 0.513.2) of the above-mentioned group 74.2% subjects were diagnosed with CPHD, while 25.8% patients with isolated growth hormone deficiency (GHD). Two children with initially short stature were confirmed with GHD. As a result of the parents' decision, growth hormone therapy was either not started or discontinued. During further follow-up, however, the children achieved normal height.

CONCLUSIONS

Children with PSIS present a diverse clinical picture and should be observed because of the risk of further pituitary disorders. In the differential diagnosis of hypoglycemia in the neonatal period and in infancy, hypopituitarism should be considered. The phenomenon of normal growth in patients with confirmed growth hormone deficiency has been observed, although is not fully understood.

Diagnosis and Management of Central Congenital Hypothyroidism

Central congenital hypothyroidism (CH) is defined as thyroid hormone (TH) deficiency at birth due to insufficient stimulation by the pituitary of the thyroid gland. The incidence of central CH is currently estimated at around 1:13,000. Central CH may occur in isolation, but in the majority of cases (60%) it is part of combined pituitary hormone deficiencies (CPHD). In recent years several novel genetic causes of isolated central CH have been discovered (IGSF1, TBL1X, IRS4), and up to 90% of isolated central CH cases can be genetically explained. For CPHD the etiology usually remains unknown, although pituitary stalk interruption syndrome does seem to be the most common anatomic pituitary malformation associated with CPHD. Recent studies have shown that central CH is a more severe condition than previously thought, and that early detection and treatment leads to good neurodevelopmental outcome. However, in the neonatal period the clinical diagnosis is often missed despite hospital admission because of feeding problems, hypoglycemia and prolonged jaundice. This review provides an update on the etiology and prognosis of central CH, and a practical approach to diagnosis and management of this intriguing condition.