A novel NFKB2 mutation in a Chinese patient with DAVID syndrome

Clinical, Immunological, and Genetic Features in Patients with NFKB1 and NFKB2 Mutations: a Systematic Review

BACKGROUND

Inborn errors of immunity (IEIs) encompass various diseases with diverse clinical and immunological symptoms. Determining the genotype-phenotype of different variants in IEI entity precisely is challenging, as manifestations can be heterogeneous even in patients with the same mutated gene.

OBJECTIVE

In the present study, we conducted a systematic review of patients recorded with NFKB1 and NFKB2 mutations, two of the most frequent monogenic IEIs.

METHODS

The search for relevant literature was conducted in databases including Web of Science, PubMed, and Scopus. Information encompassing demographic, clinical, immunological, and genetic data was extracted from cases reported with mutations in NFKB1 and NFKB2. The comprehensive features of manifestations in patients were described, and a comparative analysis of primary characteristics was conducted between individuals with NFKB1 loss of function (LOF) and NFKB2 (p52-LOF/IκBδ-gain of function (GOF)) variants.

RESULTS

A total of 397 patients were included in this study, 257 had NFKB1 mutations and 140 had NFKB2 mutations. There were 175 LOF cases in NFKB1 and 122 p52LOF/IκBδGOF cases in NFKB2 pivotal groups with confirmed functional implications. NFKB1LOF and p52LOF/IκBδGOF predominant cases (81.8% and 62.5% respectively) initially presented with a CVID-like phenotype. Patients with NFKB1LOF variants often experienced hematologic autoimmune disorders, whereas p52LOF/IκBδGOF patients were more susceptible to other autoimmune diseases. Viral infections were markedly higher in p52LOF/IκBδGOF cases compared to NFKB1LOF (P-value < 0.001). NFKB2 (p52LOF/IκBδGOF) patients exhibited a greater prevalence of ectodermal dysplasia and pituitary gland involvement than NFKB1LOF patients. Most NFKB1LOF and p52LOF/IκBδGOF cases showed low CD19 + B cells, with p52LOF/IκBδGOF having more cases of this type. Low memory B cells were more common in p52LOF/IκBδGOF patients.

CONCLUSIONS

Patients with NFKB2 mutations, particularly p52LOF/IκBδGOF, are at higher risk of viral infections, pituitary gland involvement, and ectodermal dysplasia compared to patients with NFKB1LOF mutations. Genetic testing is essential to resolve the initial complexity and confusion surrounding clinical and immunological features. Emphasizing the significance of functional assays in determining the probability of correlations between mutations and immunological and clinical characteristics of patients is crucial.

Deficient anterior pituitary with common variable immune deficiency (DAVID syndrome): a new case and literature reports

Deficient anterior pituitary with common variable immune deficiency (DAVID) syndrome is a rare condition characterized by adrenocorticotropic hormone (ACTH) deficiency and primary hypogammaglobulinemia. It is due to heterozygous mutations of the nuclear factor kappa-B subunit 2 (NFKB2) gene. Only a few isolated cases have been reported since its first description by our team. Through the international multicenter GENHYPOPIT network, we identified a new case of DAVID syndrome. We then conducted an extensive review of the DAVID syndrome cases published from 2012 to 2022. A 7-year-old boy was diagnosed with symptomatic hypoglycemia revealing ACTH deficiency. Laboratory tests showed asymptomatic hypogammaglobulinemia. He harbored a heterozygous point mutation in NFKB2 gene (c.2600C > T, p.Ala867Val). His management included hydrocortisone replacement treatment, and he also received subcutaneous immunoglobulins during the Covid-19 pandemic. We analyzed 28 cases of DAVID syndrome with ACTH deficiency. ACTH deficiency was the only hormone deficiency in 79% of patients, but some patients harbored growth hormone (GH) and thyroid stimulating hormone (TSH) deficiencies. The first presenting symptoms were sinus/pulmonary infections (82%, mean age of 3 years) and alopecia (mean age of 4.7 years). ACTH deficiency was the third presenting condition (mean age at diagnosis of 8.6 years). All patients had hypogammaglobulinemia (decreased IgA and IgM levels), and 57% of patients had at least one autoimmune manifestation. Heterozygous mutations at the 3'end of the NFKB2 gene, coding for the C-terminal domain of the protein, were identified in all cases. Better knowledge of DAVID syndrome will help clinicians make an early diagnosis to avoid life-threatening complications.

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.