A Case Report of Hypoglycemia and Hypogammaglobulinemia: DAVID Syndrome in a Patient With a Novel NFKB2 Mutation

Case Report: A child with NFKB1 haploinsufficiency explaining the linkage between immunodeficiency and short stature

We report the case of a patient with common variable immunodeficiency (CVID) presenting with short stature and treated with recombinant human growth hormone (rhGH). Whole exome sequencing revealed a novel single-nucleotide duplication in the NFKB1 gene (c.904dup, p.Ser302fs), leading to a frameshift and thus causing NFKB1 haploinsufficiency. The variant was considered pathogenic and was later found in the patient's mother, also affected by CVID. This is the first reported case of a patient with CVID due to NFKB1 mutation presenting with short stature. We analyzed the interconnection between NFKB1 and GH - IGF-1 pathways and we hypothesized a common ground for both CVID and short stature in our patient.

The search for a unifying diagnosis involving neurological, endocrine and immune dysfunction: a case report of a novel presentation of DAVID syndrome

BACKGROUND

We report a novel presentation of deficit in anterior pituitary function with variable immune deficiency (DAVID) syndrome in a healthy young girl presenting in Addisonian crisis with raised intracranial pressure. Nearly all cases of DAVID syndrome described in the literature have presented with recurrent infections and variable immunodeficiency. Pseudotumour cerebri has not been reported in DAVID syndrome to date.

CASE PRESENTATION

A four-year-old girl represented to hospital with vomiting, confusion and diplopia after ten days of tiredness, neck and abdominal pain, and headache. Her cranial nerve examination demonstrated a right abducens nerve palsy and papilloedema, and she was found to have ketotic hypoglycaemia and hypocortisolaemia secondary to adrenocorticotrophic hormone (ACTH) deficiency. Her neuroimaging was consistent with pseudotumour cerebri, and her lumbar puncture opening pressure confirmed raised intracranial pressure (30-40 cmH₂O). Cerebrospinal fluid analysis was normal. The patient's symptoms improved with hydrocortisone replacement and acetazolamide, but the raised intracranial pressure recurred after acetazolamide was discontinued. She was subsequently found to have panhypogammaglobulinaemia, and DAVID syndrome was diagnosed. Genetic testing demonstrated a truncating mutation in the NFKB2 gene c.2557C > T, p.(Arg853*).

CONCLUSIONS

This case demonstrates pseudotumour cerebri as a novel neurological presentation of DAVID syndrome, highlights the rare association between adrenal insufficiency and intracranial hypertension, and shows the challenges in diagnosing isolated ACTH deficiency. We emphasise that cortisol should be checked in pre-pubertal children with pseudotumour cerebri and a diagnosis of DAVID syndrome considered in those presenting with low cortisol and neurological symptoms.

Screening patients with autoimmune endocrine disorders for cytokine autoantibodies reveals monogenic immune deficiencies

BACKGROUND

Autoantibodies against type I interferons (IFN) alpha (α) and omega (ω), and interleukins (IL) 17 and 22 are a hallmark of autoimmune polyendocrine syndrome type 1 (APS-1), caused by mutations in the autoimmune regulator (AIRE) gene. Such antibodies are also seen in a number of monogenic immunodeficiencies.

OBJECTIVES

To determine whether screening for cytokine autoantibodies (anti-IFN-ω and anti-IL22) can be used to identify patients with monogenic immune disorders.

METHODS

A novel ELISA assay was employed to measure IL22 autoantibodies in 675 patients with autoimmune primary adrenal insufficiency (PAI) and a radio immune assay (RIA) was used to measure autoantibodies against IFN-ω in 1778 patients with a variety of endocrine diseases, mostly of autoimmune aetiology. Positive cases were sequenced for all coding exons of the AIRE gene. If no AIRE mutations were found, we applied next generation sequencing (NGS) to search for mutations in immune related genes.

RESULTS

We identified 29 patients with autoantibodies against IFN-ω and/or IL22. Of these, four new APS-1 cases with disease-causing variants in AIRE were found. In addition, we identified two patients with pathogenic heterozygous variants in CTLA4 and NFKB2, respectively. Nine rare variants in other immune genes were identified in six patients, although further studies are needed to determine their disease-causing potential.

CONCLUSION

Screening of cytokine autoantibodies can efficiently identify patients with previously unknown monogenic and possible oligogenic causes of autoimmune and immune deficiency diseases. This information is crucial for providing personalised treatment and follow-up of patients and their relatives.

Insights into non-classic and emerging causes of hypopituitarism

Hypopituitarism is defined as one or more partial or complete pituitary hormone deficiencies, which are related to the anterior and/or posterior gland and can have an onset in childhood or adulthood. The most common aetiology is a sellar or suprasellar lesion, often an adenoma, which causes hypopituitarism due to tumour mass effects, or the effects of surgery and/or radiation therapy. However, other clinical conditions, such as traumatic brain injury, and autoimmune and inflammatory diseases, can result in hypopituitarism, and there are also genetic causes of hypopituitarism. Furthermore, the use of immune checkpoint inhibitors to treat cancer is increasing the risk of hypopituitarism, with a pattern of hormone defects that is different from the classic patterns and depends on mechanisms that are specific for each drug. Moreover, autoantibody production against the pituitary and hypothalamus has been demonstrated in studies investigating the development or worsening of some cases of hypopituitarism. Finally, evidence suggests that posterior pituitary damage can affect oxytocin secretion. The aim of this Review is to summarize current knowledge on non-classic and emerging causes of hypopituitarism, so as to help clinicians improve early identification, avoid life-threatening events and improve the clinical care and quality of life of patients at risk of hypopituitarism.

Autoimmunity and immunodeficiency

PURPOSE OF REVIEW

Advances in genomics and animal models of human disease have enabled the discovery of mechanisms important for host immunity and self-tolerance. Here, we summarize conceptual and clinical discoveries identified from 2018 to 2019 in the field of primary immunodeficiencies and autoimmunity.

RECENT FINDINGS

Three new primary immunodeficiencies with autoimmunity were identified and the clinical phenotypes of NFKB1 haploinsufficiency and RASGRP1 deficiency were expanded. A diversity of novel mechanisms leading to autoimmunity associated with primary immunodeficiencies (PIDs) was reported, including pathways important for the metabolism and function of regulatory T cells and germinal B cells, the contribution of neutrophil extracellular traps to plasmacytoid dendritic cell activation and the influence of commensal bacteria on the generation of autoantibodies. With regard to therapeutic developments in the field, we highlight the use of janus kinase inhibitors for immune dysregulation associated with gain-of-function variants in STAT1 and STAT3, as well as the risks of persistent hypogammaglobulinemia associated with rituximab treatment.

SUMMARY

Mechanistic studies of PIDs with autoimmunity elucidate key principles governing the balance between immune surveillance and self-tolerance.

Symptomatic hypoglycemia in a child with common variable immunodeficiency: Deficient anterior pituitary with variable immune deficiency (DAVID) syndrome

Deficient anterior pituitary with variable immune deficiency (DAVID) syndrome is a rare condition characterized by symptomatic ACTH deficiency and primary hypogammaglobulinemia, caused by pathogenic variants of the nuclear factor kappa-B subunit 2 (NF-κB2) gene. We report the case of a 9-yr-old boy diagnosed with common variable immunodeficiency at the age of 3, who is under monthly intravenous immunoglobulin. The patient was admitted twice to the pediatric emergency service at the age of 9 due to symptomatic hypoglycemic events. During the hypoglycemic crisis, serum cortisol was low (< 0.1 μg/dL), ACTH level was inappropriately low (4.4 ng/L) and the ACTH stimulation test failed to raise the blood cortisol level. Pituitary magnetic resonance imaging showed a hypoplastic pituitary. Other pituitary deficiencies, primary hyperinsulinism and other metabolic diseases were excluded. He started hydrocortisone replacement treatment while maintaining immunoglobulin substitution and he remains asymptomatic. Molecular analysis revealed the heterozygous nonsense pathogenic variant, c.2557C>T (Arg853Ter) in the NF-κB2 gene. Thus, symptomatic hypoglycemia in a child with primary immunodeficiency should raise the suspicion of DAVID syndrome, prompting NF-κB2 molecular analysis, to allow timely and appropriated therapy and genetic counseling.

Endocrine Disorders Are Prominent Clinical Features in Patients With Primary Antibody Deficiencies

Background: Primary antibody deficiencies (PADs) and anterior pituitary dysfunction are both rare conditions. However, recent studies have remarkably reported the occurrence of anterior pituitary dysfunction in PAD patients. Methods: In this cross-sectional, single-center study we evaluated the prevalence of endocrine disorders in adult PAD patients. Our study focused on common variable immunodeficiency (CVID), immunoglobulin G (IgG) subclass deficiency (IgGSD), and specific anti-polysaccharide antibody deficiency (SPAD). We assessed hormone levels, performed provocative tests and genetic testing in a subset of patients by direct sequencing of the nuclear factor kappa beta subunit 2 (NFKB2) gene and primary immunodeficiency (PID) gene panel testing by whole exome sequencing (WES). Results: Our results demonstrated that one out of 24 IgGSD/SPAD patients had secondary hypothyroidism and three out of 9 men with IgGSD/SPAD had secondary hypogonadism. Premature ovarian failure was observed in four out of 9 women with CVID and primary testicular failure in one out of 15 men with CVID. In two out of 26 CVID patients we found partial adrenal insufficiency (AI) and in one out of 18 patients with IgGSD/SPAD secondary AI was found. Moreover, in one out of 23 patients with CVID and in two out of 17 patients with IgGSD/SPAD severe growth hormone deficiency (GHD) was found, while one patient with IgGSD/SPAD showed mild GHD. Combined endocrine disorders were detected in two women with CVID (either partial secondary AI or autoimmune thyroiditis with primary hypogonadism) and in three men with IgGSD/SPAD (two with either mild GHD or secondary hypothyroidism combined with secondary hypogonadism, and one man with secondary AI and severe GHD). Genetic testing in a subset of patients did not reveal pathogenic variants in NFKB2 or other known PID-associated genes. Conclusion: This is the first study to describe a high prevalence of both anterior pituitary and end-organ endocrine dysfunction in adult PAD patients. As these endocrine disorders may cause considerable health burden, assessment of endocrine axes should be considered in PAD patients.

Central diabetes insipidus in a patient with NFKB2 mutation: Expanding the endocrine phenotype in DAVID syndrome

CONTEXT

DAVID syndrome is a recently described, rare disorder characterized by anterior pituitary hormone deficiencies and common variable immunodeficiency associated with NFKB2 mutations. Posterior pituitary hormone deficiencies have not been reported in patients with DAVID syndrome.

CASE DESCRIPTION

We report a pediatric patient who initially presented with hypogammaglobulinemia and alopecia totalis, who was identified to have a de novo NFKB2 mutation at one year of age. He developed central diabetes insipidus and central adrenal insufficiency at three and four years of age respectively. At seven years of age, he had not developed growth hormone or thyrotropin deficiencies. Whole exome sequencing ruled out known genetic causes of central diabetes insipidus, adrenal insufficiency and hypopituitarism.

CONCLUSION

To our knowledge, this is the first report of central diabetes insipidus in a patient with DAVID syndrome due to an NFKB2 mutation. This case report expands the evolving endocrine phenotype associated with NFKB2 mutations beyond anterior pituitary deficiencies.

Pathogenic NFKB2 variant in the ankyrin repeat domain (R635X) causes a variable antibody deficiency

Genetic studies are identifying an increasing number of monogenic causes of Common Variable Immunodeficiency (CVID). Pathogenic variants in the C-terminus of NFKB2 have been identified in the subset of CVID patients whose immunodeficiency is associated with ectodermal dysplasia and central adrenal insufficiency. We describe 2 unrelated CVID pedigrees with 4 cases of pathogenic stop gain variants (c.1903C > T) in the ankyrin repeat domain (ARD) of NF-κB2, leading to a premature truncation of the protein at p.Arg635Term (R635X). By immunophenotyping and functional ex vivo B- and T-cell experiments we characterized the variant by reduced class-switched memory B-cell counts and immature plasmablasts, unable to produce IgG and IgA. Features of a poor proliferative T-cell response and reduced expansion of CD4⁺CXCR5⁺ T cells was only observed in the two clinically affected index cases without any clear clinical correlate. In conclusion, pathogenic stop variants in the ARD of NFKB2 can cause 'infection-only' CVID with an abnormal B-cell phenotype and a variable clinical penetrance.

NF-κB pathway and the Goldilocks principle: Lessons from human disorders of immunity and inflammation

Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) signaling pathways play a key role in various cell processes related to host immunity. The last few years have seen an explosion of disorders associated with NF-κB components from core members of the canonical and noncanonical cascades to adaptor protein and ubiquitination-related enzymes. Disease phenotypes have extended beyond susceptibility to infections and include autoimmunity, lymphoproliferation, atopy, and inflammation. Concurrently, studies are unveiling a tightly regulated system marked by extensive cross-talk between the canonical and noncanonical pathways, as well as among the NF-κB and other signaling pathways. As the rate of discovery in the realm of NF-κB defects accelerates, this review presents a timely summary of major known defects causing human disease, as well as diagnostic, therapeutic, and research challenges and opportunities.

Clinical and Immunological Phenotype of Patients With Primary Immunodeficiency Due to Damaging Mutations in NFKB2

Non-canonical NF-κB-pathway signaling is integral in immunoregulation. Heterozygous mutations in NFKB2 have recently been established as a molecular cause of common variable immunodeficiency (CVID) and DAVID-syndrome, a rare condition combining deficiency of anterior pituitary hormone with CVID. Here, we investigate 15 previously unreported patients with primary immunodeficiency (PID) from eleven unrelated families with heterozygous NFKB2-mutations including eight patients with the common p.Arg853^* nonsense mutation and five patients harboring unique novel C-terminal truncating mutations. In addition, we describe the clinical phenotype of two patients with proximal truncating mutations. Cohort analysis extended to all 35 previously published NFKB2-cases revealed occurrence of early-onset PID in 46/50 patients (mean age of onset 5.9 years, median 4.0 years). ACTH-deficiency occurred in 44%. Three mutation carriers have deceased, four developed malignancies. Only two mutation carriers were clinically asymptomatic. In contrast to typical CVID, most patients suffered from early-onset and severe disease manifestations, including clinical signs of T cell dysfunction e.g., chronic-viral or opportunistic infections. In addition, 80% of patients suffered from (predominately T cell mediated) autoimmune (AI) phenomena (alopecia > various lymphocytic organ-infiltration > diarrhea > arthritis > AI-cytopenia). Unlike in other forms of CVID, auto-antibodies or lymphoproliferation were not common hallmarks of disease. Immunophenotyping showed largely normal or even increased quantities of naïve and memory CD4⁺ or CD8⁺ T-cells and normal T-cell proliferation. NK-cell number and function were also normal. In contrast, impaired B-cell differentiation and hypogammaglobinemia were consistent features of NFKB2-associated disease. In addition, an array of lymphocyte subpopulations, such as regulatory T cell, Th17-, cTFH-, NKT-, and MAIT-cell numbers were decreased. We conclude that heterozygous damaging mutations in NFKB2 represent a distinct PID entity exceeding the usual clinical spectrum of CVID. Impairment of the non-canonical NF-κB pathways affects function and differentiation of numerous lymphocyte-subpopulations and thus causes a heterogeneous, more severe form of PID phenotype with early-onset. Further characteristic features are multifaceted, primarily T cell-mediated autoimmunity, such as alopecia, lymphocytic organ infiltration, and in addition frequently ACTH-deficiency.

Central adrenal insufficiency in children and adolescents

Central adrenal insufficiency (CAI) is a life-threatening condition caused by either pituitary disease (secondary adrenal insufficiency) or impaired hypothalamic function with inadequate CRH production (tertiary adrenal insufficiency). ACTH deficiency may be isolated or, more frequently, occur in conjunction with other pituitary hormone deficiencies and midline defects. Genetic mutations of the TBX19 causing isolated CAI are rare but a number of genes encoding transcription factors involved in hypothalamic-pituitary gland development, as well as other genes including POMC and PC1, are associated with ACTH deficiency. CAI is frequently identified in congenital, malformative, genetic, and epigenetic syndromes as well as in several acquired conditions of different etiologies. The signs and symptoms vary considerably and depend on the age of onset and the number and severity of associated pituitary defects. They may include hypoglycemia, lethargy, apnea, poor feeding, prolonged cholestatic jaundice, jitteriness, seizures, and sepsis in the neonate, or nonspecific signs such as fatigue, hypotension, vomiting and hyponatremia without hyperkalemia in children. The diagnosis of CAI relies on the measurement of morning cortisol concentrations along with dynamic test for cortisol release with different stimulating agents. Early recognition of CAI and its correct management are mandatory in order to avoid both morbidity and mortality in affected neonates, children and adolescents.

Bacille Calmette-Guerin Complications in Newly Described Primary Immunodeficiency Diseases: 2010-2017

Bacille Calmette–Guerin (BCG) vaccine is widely used as a prevention strategy against tuberculosis. BCG is a live vaccine, usually given early in life in most countries. While safe to most recipients, it poses a risk to immunocompromised patients. Several primary immunodeficiency diseases (PIDD) have been classically associated with complications related to BCG vaccine. However, a number of new inborn errors of immunity have been described lately in which little is known about adverse reactions following BCG vaccination. The aim of this review is to summarize the existing data on BCG-related complications in patients diagnosed with PIDD described since 2010. When BCG vaccination status or complications were not specifically addressed in those manuscripts, we directly contacted the corresponding authors for further clarification. We also analyzed data on other mycobacterial infections in these patients. Based on our analysis, around 8% of patients with gain-of-function mutations in STAT1 had mycobacterial infections, including localized complications in 3 and disseminated disease in 4 out of 19 BCG-vaccinated patients. Localized BCG reactions were also frequent in activated PI3Kδ syndrome type 1 (3/10) and type 2 (2/18) vaccinated children. Also, of note, no BCG-related complications have been described in either CTLA4 or LRBA protein-deficient patients; and not enough information on BCG-vaccinated NFKB1 or NFKB2-deficient patients was available to drive any conclusions about these diseases. Despite the high prevalence of environmental mycobacterial infections in GATA2-deficient patients, only one case of BCG reaction has been reported in a patient who developed disseminated disease. In conclusion, BCG complications could be expected in some particular, recently described PIDD and it remains a preventable risk factor for pediatric PIDD patients.