Identification of genetic variants and phenotypic characterization of a large cohort of patients with congenital hypopituitarism and related disorders

Human Pituitary Organoids: Transcriptional Landscape Deciphered by scRNA-Seq and Stereo-Seq, with Insights into SOX3's Role in Pituitary Development

The 3D human pituitary organoid represents a promising laboratory model for investigating human pituitary diseases. Nonetheless, this technology is still in its nascent stage, with uncertainties regarding the cellular composition, intercellular interactions, and spatial distribution of the human pituitary organoids. To address these gaps, the culture conditions are systematically adjusted and the efficiency of induced pluripotent stem cells' (iPSCs') differentiation into pituitary organoids is successfully improved, achieving results comparable to or exceeding those of previous studies. Additionally, single-cell RNA-sequencing (scRNA-seq) and stereomics sequencing (Stereo-seq) are performed on the pituitary organoids for the first time, and unveil the diverse cell clusters, intricate intercellular interactions, and spatial information within the organoids. Furthermore, the SOX3 gene interference impedes the iPSCs' differentiation into pituitary organoids, thereby highlighting the potential of pituitary organoids as an ideal experimental model. Altogether, the research provides an optimized protocol for the human pituitary organoid culture and a valuable transcriptomic dataset for future explorations, laying the foundation for subsequent research in the field of pituitary organoids or pituitary diseases.

A Novel Missense Variant in LHX4 in Three Children with Multiple Pituitary Hormone Deficiency Belonging to Two Unrelated Families and Contribution of Additional GLI2 and IGFR1 Variant

BACKGROUND

Multiple genes can disrupt hypothalamic-pituitary axis development, causing multiple pituitary hormone deficiencies (MPHD). Despite advances in next-generation sequencing (NGS) identifying over 30 key genes, 85% of cases remain unsolved, indicating complex genotype-phenotype correlations and variable inheritance patterns.

OBJECTIVE

This study aimed to identify the MPHD genetics in three probands from two unrelated families.

METHODS

Family A had one affected child, while Family B had two affected siblings. All probands exhibited poor growth since birth, and family B's probands were born small for gestational age. Growth hormone deficiency was confirmed in all subjects. Family B's probands responded poorly to growth hormone treatment compared to the first patient. Furthermore, Family A's proband and Family B's younger sibling developed central hypothyroidism, while Family B's older sibling presented hypogonadotropic hypogonadism. Brain magnetic resonance imaging (MRI) revealed pituitary hypoplasia, ectopic posterior pituitary gland, and small sella turcica in all probands. Patients and their available relatives underwent NGS.

RESULTS

NGS identified the same novel and likely pathogenic LHX4 variant (c.481C>G) in all probands despite the families being unrelated. Additionally, Family A's proband carried a GLI2 variant (c.2105C>A), and Family B's probands carried an IGF1R variant (c.166G>A), both interpreted as being of uncertain significance.

CONCLUSIONS

This study confirms that heterozygous pathogenic variants of LHX4 can cause MPHD associated with a specific neuroradiological triad of abnormalities despite incomplete penetrance and variable phenotype. Moreover, the co-occurrence of the other two gene variants was debated. The IGF1R variant could explain the unusually poor response to growth hormone therapy in Family B, suggesting an oligogenic mechanism underlying the phenotype.

Phenotype and genotype of 23 patients with hypopituitarism and pathogenic GLI2 variants

OBJECTIVE

To analyze the phenotype and genotype of patients with congenital hypopituitarism (CH) and pathogenic (P) GLI2 variants.

METHODS

A large cohort of patients with hypopituitarism was screened for GLI2 variants using a next-generation sequencing panel. Genotype-phenotype correlations were then assessed using GENHYPOPIT phenotypic data.

RESULTS

Of the 39 GLI2 variants identified in 717 index cases, 17 were classified as pathogenic and likely pathogenic. All these GLI2 variants were identified in 23 patients (17 index cases and 6 relatives) with associated pituitary stalk interruption syndrome or extrapituitary manifestations. GLI2 variants were the most frequently identified genetic cause in patients with syndromic hypopituitarism (68%): 88% (15/17) of mutations were truncating variants, and 45% were de novo. Most patients with a GLI2 variant (21/23, 91%) had hypopituitarism, including 21.7% (5/23) presenting isolated growth hormone deficiency. Two patients had Kallmann syndrome. Pituitary morphological abnormalities were present in 84% of the patients with P GLI2 variants (index cases and affected relatives). The remaining signs included neurocognitive disorders (38%), hexadactyly (27%), cardiac septal defects, and renal/vesical abnormalities. A possible digenic origin (GLI2/HESX1) is proposed in one family.

CONCLUSION

In this large multicentric international cohort, GLI2 was the most frequently identified genetic cause of syndromic CH with constant association of pituitary stalk interruption syndrome or extrapituitary clinical features. In addition to polydactyly and neurocognitive disorders, cardiac and renal abnormalities were also frequently observed and should be investigated further. The variable expression of GLI2-associated phenotypes justifies further research in this area.

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.

The molecular basis of hypoprolactinaemia

Hypoprolactinaemia is an endocrinopathy which is typically encountered as part of a combined pituitary hormone deficiency picture. The vast majority of genetic causes identified to date have been in the context of congenital hypopituitarism with multiple co-existent endocrinopathies. This is primarily with its closest hormonal relation, namely growth hormone. Acquired hypoprolactinaemia is generally rare in paediatric patients, and usually occurs together with other hormonal deficiencies. Congenital hypopituitarism occurs with an incidence of 1:4,000-10,000 cases and mutations in the following transcription factors account for the majority of documented genetic causes: PROP-1, POU1F1, LHX3/4 as well as documented case reports for a smaller subset of transcription factors and other molecules implicated in lactotroph development and prolactin secretion. Isolated prolactin deficiency has been described in a number of sporadic case reports in the literature, but no cases of mutations in the gene have been described to date. A range of genetic polymorphisms affecting multiple components of the prolactin signalling pathway have been identified in the literature, ranging from RNA spliceosome mutations (RNPC3) to loss of function mutations in IGSF-1. As paediatricians gain a greater understanding of the long-term ramifications of hypoprolactinaemia in terms of metabolic syndrome, type 2 diabetes mellitus and impaired fertility, the expectation is that clinicians will measure prolactin more frequently over time. Ultimately, we will encounter further reports of hypoprolactinaemia-related clinical presentations with further genetic mutations, in turn leading to a greater insight into the molecular basis of hypoprolactinaemia in terms of signalling pathways and downstream mediators. In the interim, the greatest untapped reserve of genetic causes remains within the phenotypic spectrum of congenital hypopituitarism.

An Update on Advances in Hypopituitarism: Etiology, Diagnosis, and Current Management

This article provides an updated review of hypopituitarism (HP), an endocrine disorder characterized by a deficiency of one or more pituitary hormones. The various etiologies are reviewed, including pituitary neuroendocrine tumors (PitNETs), hypothalamic lesions, genetic mutations, and acquired factors such as head trauma, medications, neoplasms, and infiltrative diseases. It is noted that PitNETs are responsible for approximately half of the cases in adults, whereas in children the causes are predominantly congenital. Diagnosis is based on clinical evaluation and hormonal testing, with identification of the specific hormonal deficiencies essential for effective treatment. Laboratory tests present challenges and limitations that must be understood and addressed. Hormone replacement therapy is the mainstay of treatment, significantly improving patients' quality of life. It is important to know the possible interactions between hormone replacement therapies in HP. Recent advances in understanding the pathophysiology of HP and the importance of a multidisciplinary approach to the management of associated complications are discussed. This article emphasizes the need for comprehensive evaluation and continuous follow-up to optimize outcomes in patients with HP and highlights the importance of ongoing research to improve diagnostic and treatment strategies.

The clinical and genetic aspects of six individuals with GH1 variants and isolated growth hormone deficiency type II

Background

Isolated growth hormone deficiency type II (IGHD II) is an autosomal dominant disorder characterized by a GH1 gene variant resulting in a significant reduction in growth hormone (GH) secretion and a subsequent decrease of plasma insulin-like growth factor 1 (IGF-1) levels and eventual growth impairment.

Objective

This study aimed to identify causative variants in six Chinese families with IGHD II, exploring both clinical and genetic characteristics.

Methods

Detailed clinical data, including clinical presentations, physical charateristics, medical and family histories, as well as genetic test results, were systematically examined.

Results

Six children, comprising four males and two females, with a mean age of 4.64 ± 1.15 years, exhibited short stature with a mean height of -3.95 ± 1.41 SDS. Four of them had a family history of short stature, while one patient presented with pulmonary hypertension. All children demonstrated GH deficiency in growth hormone stimulation tests (mean peak GH value: 2.83 ± 2.46 ng/mL). Exome sequencing for the six patients and targeted gene sequencing for their family members revealed heterozygous variants in the GH1 gene, including Exon2-5del, c.334T>C, c.291 + 1G>A, c.291 + 2T>A, 1.5 kb deletion, and 1.7 kb deletion, with four variants being novel. Four patients underwent human recombinant growth hormone (rhGH) replacement therapy, initiating treatment at a mean age of 4.6 ± 0.7 years. The mean height increase in patients was 1.21 ± 0.3 SDS in the first six months of treatment and 1.79 ± 0.15 SDS in the first year.

Conclusion

Our findings contribute to expanding the genotypic and phenotypic spectra of individuals with IGHD II.

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.

Hypopituitarism

Partial or complete deficiency of anterior or posterior pituitary hormone production leads to central hypoadrenalism, central hypothyroidism, hypogonadotropic hypogonadism, growth hormone deficiency, or arginine vasopressin deficiency depending on the hormones affected. Hypopituitarism is rare and likely to be underdiagnosed, with an unknown but rising incidence and prevalence. The most common cause is compressive growth or ablation of a pituitary or hypothalamic mass. Less common causes include genetic mutations, hypophysitis (especially in the context of cancer immunotherapy), infiltrative and infectious disease, and traumatic brain injury. Clinical features vary with timing of onset, cause, and number of pituitary axes disrupted. Diagnosis requires measurement of basal circulating hormone concentrations and confirmatory hormone stimulation testing as needed. Treatment is aimed at replacement of deficient hormones. Increased mortality might persist despite treatment, particularly in younger patients, females, and those with arginine vasopressin deficiency. Patients with complex diagnoses, pregnant patients, and adolescent pituitary-deficient patients transitioning to adulthood should ideally be managed at a pituitary tumour centre of excellence.

Diagnosing and treating anterior pituitary hormone deficiency in pediatric patients

Hypopituitarism, or the failure to secrete hormones produced by the anterior pituitary (adenohypophysis) and/or to release hormones from the posterior pituitary (neurohypophysis), can be congenital or acquired. When more than one pituitary hormone axis is impaired, the condition is known as combined pituitary hormone deficiency (CPHD). The deficiency may be primarily due to a hypothalamic or to a pituitary disorder, or concomitantly both, and has a negative impact on target organ function. This review focuses on the pathophysiology, diagnosis and management of anterior pituitary hormone deficiency in the pediatric age. Congenital hypopituitarism is generally due to genetic disorders and requires early medical attention. Exposure to toxicants or intrauterine infections should also be considered as potential etiologies. The molecular mechanisms underlying the fetal development of the hypothalamus and the pituitary are well characterized, and variants in the genes involved therein may explain the pathophysiology of congenital hypopituitarism: mutations in the genes expressed in the earliest stages are usually associated with syndromic forms whereas variants in genes involved in later stages of pituitary development result in non-syndromic forms with more specific hormone deficiencies. Tumors or lesions of the (peri)sellar region, cranial radiation therapy, traumatic brain injury and, more rarely, other inflammatory or infectious lesions represent the etiologies of acquired hypopituitarism. Hormone replacement is the general strategy, with critical periods of postnatal life requiring specific attention.

Knockout mice with pituitary malformations help identify human cases of hypopituitarism

BACKGROUND

Congenital hypopituitarism (CH) and its associated syndromes, septo-optic dysplasia (SOD) and holoprosencephaly (HPE), are midline defects that cause significant morbidity for affected people. Variants in 67 genes are associated with CH, but a vast majority of CH cases lack a genetic diagnosis. Whole exome and whole genome sequencing of CH patients identifies sequence variants in genes known to cause CH, and in new candidate genes, but many of these are variants of uncertain significance (VUS).

METHODS

The International Mouse Phenotyping Consortium (IMPC) is an effort to establish gene function by knocking-out all genes in the mouse genome and generating corresponding phenotype data. We used mouse embryonic imaging data generated by the Deciphering Mechanisms of Developmental Disorders (DMDD) project to screen 209 embryonic lethal and sub-viable knockout mouse lines for pituitary malformations.

RESULTS

Of the 209 knockout mouse lines, we identified 51 that have embryonic pituitary malformations. These genes not only represent new candidates for CH, but also reveal new molecular pathways not previously associated with pituitary organogenesis. We used this list of candidate genes to mine whole exome sequencing data of a cohort of patients with CH, and we identified variants in two unrelated cases for two genes, MORC2 and SETD5, with CH and other syndromic features.

CONCLUSIONS

The screening and analysis of IMPC phenotyping data provide proof-of-principle that recessive lethal mouse mutants generated by the knockout mouse project are an excellent source of candidate genes for congenital hypopituitarism in children.