Confirmation of Hyperimmunoglobulin E Syndrome in Two Patients with an Ocular Problem: Detection of Two New DOCK8 Mutations.

Early diagnosis of primary immunodeficiencies is crucial for timely treatment and preventing unwanted complications. Next-generation sequencing (NGS) and detailed clinical and immunological evaluation can help early detect such disorders. This study aimed to confirm the diagnosis of two cases of autosomal recessive hyper-immunoglobulin E (IgE) syndrome (AR-HIES), presenting with irreversible eye involvement. Two unrelated patients with suspected AR-HIES were referred to the Immunology, Asthma and Allergy Research Institute (IAARI), Tehran, Iran. Immunological screening tests were performed for AR-HIES, which showed elevated serum IgE levels, eosinophilia, and low T-lymphocyte responses. NGS was performed, and the results were confirmed by Sanger sequencing. Sequence analysis showed a mutation in intron 17 of the dedicator of cytokinesis 8 (DOCK8) gene in the first patient, and a homozygous three base-pair deletion in exon 45 of DOCK8 in the second patient. This is the first time such mutations are reported and these variants are predicted to be damaging. Both patients suffered from persistent viral infections along with cytomegalovirus (CMV) retinitis. Suspicion of these two novel DOCK8 mutations can benefit patients presenting with recalcitrant ophthalmic viral involvements and relevant immunological test results. This would lead to earlier referrals for immunologic and genetic confirmation and thus, a more timely intervention with hematopoietic stem cell transplantation (HSCT).

Genetic Analysis of a Cohort of 275 Patients with Hyper-IgE Syndromes and/or Chronic Mucocutaneous Candidiasis.

Hyper-IgE syndromes and chronic mucocutaneous candidiasis constitute rare primary immunodeficiency syndromes with an overlapping clinical phenotype. In recent years, a growing number of underlying genetic defects have been identified. To characterize the underlying genetic defects in a large international cohort of 275 patients, of whom 211 had been clinically diagnosed with hyper-IgE syndrome and 64 with chronic mucocutaneous candidiasis, targeted panel sequencing was performed, relying on Agilent HaloPlex and Illumina MiSeq technologies. The targeted panel sequencing approach allowed us to identify 87 (32 novel and 55 previously described) mutations in 78 patients, which generated a diagnostic success rate of 28.4%. Specifically, mutations in DOCK8 (26 patients), STAT3 (21), STAT1 (15), CARD9 (6), AIRE (3), IL17RA (2), SPINK5 (3), ZNF341 (2), CARMIL2/RLTPR (1), IL12RB1 (1), and WAS (1) have been detected. The most common clinical findings in this cohort were elevated IgE (81.5%), eczema (71.7%), and eosinophilia (62.9%). Regarding infections, 54.7% of patients had a history of radiologically proven pneumonia, and 28.3% have had other serious infections. History of fungal infection was noted in 53% of cases and skin abscesses in 52.9%. Skeletal or dental abnormalities were observed in 46.2% of patients with a characteristic face being the most commonly reported feature (23.1%), followed by retained primary teeth in 18.9% of patients. Targeted panel sequencing provides a cost-effective first-line genetic screening method which allows for the identification of mutations also in patients with atypical clinical presentations and should be routinely implemented in referral centers.

Targeted Gene Panel Sequencing for Early-onset Inflammatory Bowel Disease and Chronic Diarrhea.

BACKGROUND: In contrast to adult-onset inflammatory bowel disease (IBD), where many genetic loci have been shown to be involved in complex disease etiology, early-onset IBD (eoIBD) and associated syndromes can sometimes present as monogenic conditions. As a result, the clinical phenotype and ideal disease management in these patients often differ from those in adult-onset IBD. However, due to high costs and the complexity of data analysis, high-throughput screening for genetic causes has not yet become a standard part of the diagnostic work-up of eoIBD patients. METHODS: We selected 28 genes of interest associated with monogenic IBD and performed targeted panel sequencing in 71 patients diagnosed with eoIBD or early-onset chronic diarrhea to detect causative variants. We compared these results to whole-exome sequencing (WES) data available for 25 of these patients. RESULTS: Target coverage was significantly higher in the targeted gene panel approach compared with WES, whereas the cost of the panel was considerably lower (approximately 25% of WES). Disease-causing variants affecting protein function were identified in 5 patients (7%), located in genes of the IL10 signaling pathway (3), WAS (1), and DKC1 (1). The functional effects of 8 candidate variants in 5 additional patients (7%) are under further investigation. WES did not identify additional causative mutations in 25 patients. CONCLUSIONS: Targeted gene panel sequencing is a fast and effective screening method for monogenic causes of eoIBD that should be routinely established in national referral centers.

Screening of 181 Patients With Antibody Deficiency for Deficiency of Adenosine Deaminase 2 Sheds New Light on the Disease in Adulthood.

OBJECTIVE: We aimed to test the relevance of deficiency of adenosine deaminase 2 (DADA2) in patients with antibody deficiency and describe the clinical picture of the disease in adulthood. METHODS: We screened for DADA2 in a cohort of 181 patients with antibody deficiency with or without vascular lesions using next-generation sequencing and targeted Sanger sequencing. All mutations were confirmed by determining the ADA2 enzymatic activity levels in dried plasma spots. Clinical data and laboratory values were collected in a standardized format. RESULTS: Following the diagnosis of 2 siblings in the index family, we identified 9 additional affected patients with compound heterozygous or homozygous CECR1 mutations, containing 6 novel and 4 previously published mutations. The patients' age at evaluation ranged from 13 to 51 years, with a median age of 22 years. Clinically, we saw a broad phenotype, ranging from isolated antibody deficiency to recurrent strokes. All but 1 patient had low numbers of memory B cells. Moreover, B cell function seemed to correlate with inflammation. CONCLUSION: Taken together, our findings indicate that DADA2 presents not only with vasculopathy but also with an immunodeficiency of the B cell compartment. Therefore, patients with antibody deficiency should be screened for DADA2. Anti-tumor necrosis factor treatment might improve immunologic features over time and might be considered in patients without vascular manifestations but with elevated inflammation markers. Conservative management has so far proven to be the choice for our less severely affected adolescent and adult DADA2 patients; however, in patients with severe cytopenias and bone marrow failure, hematopoietic stem cell transplantation should be considered.

Association of CLEC16A with human common variable immunodeficiency disorder and role in murine B cells.

Common variable immunodeficiency disorder (CVID) is the most common symptomatic primary immunodeficiency in adults, characterized by B-cell abnormalities and inadequate antibody response. CVID patients have considerable autoimmune comorbidity and we therefore hypothesized that genetic susceptibility to CVID may overlap with autoimmune disorders. Here, in the largest genetic study performed in CVID to date, we compare 778 CVID cases with 10,999 controls across 123,127 single-nucleotide polymorphisms (SNPs) on the Immunochip. We identify the first non-HLA genome-wide significant risk locus at CLEC16A (rs17806056, P=2.0 × 10(-9)) and confirm the previously reported human leukocyte antigen (HLA) associations on chromosome 6p21 (rs1049225, P=4.8 × 10(-16)). Clec16a knockdown (KD) mice showed reduced number of B cells and elevated IgM levels compared with controls, suggesting that CLEC16A may be involved in immune regulatory pathways of relevance to CVID. In conclusion, the CLEC16A associations in CVID represent the first robust evidence of non-HLA associations in this immunodeficiency condition.

Deficiency of caspase recruitment domain family, member 11 (CARD11), causes profound combined immunodeficiency in human subjects.

BACKGROUND: Profound combined immunodeficiency can present with normal numbers of T and B cells, and therefore the functional defect of the cellular and humoral immune response is often not recognized until the first severe clinical manifestation. Here we report a patient of consanguineous descent presenting at 13 months of age with hypogammaglobulinemia, Pneumocystis jirovecii pneumonia, and a suggestive family history. OBJECTIVE: We sought to identify the genetic alteration in a patient with combined immunodeficiency and characterize human caspase recruitment domain family, member 11 (CARD11), deficiency. METHODS: Molecular, immunologic, and functional assays were performed. RESULTS: The immunologic characterization revealed only subtle changes in the T-cell and natural killer cell compartment, whereas B-cell differentiation, although normal in number, was distinctively blocked at the transitional stage. Genetic evaluation revealed a homozygous deletion of exon 21 in CARD11 as the underlying defect. This deletion abrogated protein expression and activation of the canonical nuclear factor κB (NF-κB) pathway in lymphocytes after antigen receptor or phorbol 12-myristate 13-acetate stimulation, whereas CD40 signaling in B cells was preserved. The abrogated activation of the canonical NF-κB pathway was associated with severely impaired upregulation of inducible T-cell costimulator, OX40, cytokine production, proliferation of T cells, and B cell-activating factor receptor expression on B cells. CONCLUSION: Thus in patients with CARD11 deficiency, the combination of impaired activation and especially upregulation of inducible T-cell costimulator on T cells, together with severely disturbed peripheral B-cell differentiation, apparently leads to a defective T-cell/B-cell cooperation and probably germinal center formation and clinically results in severe immunodeficiency. This report discloses the crucial and nonredundant role of canonical NF-κB activation and specifically CARD11 in the antigen-specific immune response in human subjects.

Predictors and prevalence of paraganglioma syndrome associated with mutations of the SDHC gene.

CONTEXT: Paraganglioma syndrome includes inherited head and neck paragangliomas (HNPs) and adrenal or extra-adrenal pheochromocytomas and are classified according to the susceptibility genes SDHB, SDHC, and SDHD. In contrast with those with germline mutations of the SDHB and SDHD genes, clinical and genetic data on patients with mutations of SDHC are scarce. OBJECTIVE: To determine the prevalence and clinical characteristics of SDHC mutation carriers compared with patients with SDHB and SDHD mutations and with sporadic cases. DESIGN, SETTING, AND PATIENTS: Genetic screening for SDHC mutations in an international HNP registry of 121 unrelated index cases and in 371 sporadic cases from a pheochromocytoma registry, conducted January 1, 2001, until December 31, 2004. Identified index cases and affected relatives were clinically evaluated. MAIN OUTCOME MEASURES: Prevalence of and clinical findings for SDHC mutation-associated HNPs vs those with SDHB and SDHD mutations. RESULTS: The prevalence of SDHC carriers was 4% in HNP but 0% in pheochromocytoma index cases. None of the SDHC mutation carriers had signs of pheochromocytoma. We compared HNPs in 22 SDHC mutation carriers with the HNPs of SDHB (n = 15) and SDHD (n = 42) mutation carriers and with 90 patients with sporadic HNPs. Location, number of tumors, malignancy, and age were different: more carotid body tumors were found in SDHC (13/22 [59%]) than in sporadic HNPs (29/90 [32%], P = .03), as well as fewer instances of multiple tumors in SDHC (2/22) than in SDHD (24/42; P<.001), 0 malignant tumors in SDHC vs 6/15 in SDHB (P = .002), and younger age at diagnosis in SDHC than in sporadic HNPs (45 vs 52 years; P = .03). CONCLUSIONS: Patients with HNP, but not those with pheochromocytoma, harbor SDHC mutations in addition to those in SDHB and SDHD. In total, more than one quarter of HNP patients carry a mutation in 1 of these 3 genes. Head and neck paragangliomas associated with SDHC mutations are virtually exclusively benign and seldom multifocal. Analysis for germline mutations of SDHC is recommended in apparently sporadic HNP to identify risk of inheritance.

Distinct clinical features of paraganglioma syndromes associated with SDHB and SDHD gene mutations.

CONTEXT: Germline mutations of the genes encoding succinate dehydrogenase subunits B (SDHB) and D (SDHD) predispose to paraganglioma syndromes type 4 (PGL-4) and type 1 (PGL-1), respectively. In both syndromes, pheochromocytomas as well as head and neck paragangliomas occur; however, details for individual risks and other clinical characteristics are unknown. OBJECTIVE: To determine the differences in clinical features in carriers of SDHB mutations and SDHD mutations. DESIGN, SETTING, AND PATIENTS: Population-based genetic screening for SDHB and SDHD germline mutations in 417 unrelated patients with adrenal or extra-adrenal abdominal or thoracic pheochromocytomas (n = 334) or head and neck paragangliomas (n = 83), but without syndromic features, from 2 registries based in Germany and central Poland, conducted from April 1, 2000, until May 15, 2004. MAIN OUTCOME MEASURES: Demographic and clinical findings with respect to gene mutation in SDHB vs SDHD compared with nonmutation carriers. RESULTS: A total of 49 (12%) of 417 registrants carried SDHB or SDHD mutations. In addition, 28 SDHB and 23 SDHD mutation carriers were newly detected among relatives of these carriers. Comparison of 53 SDHB and 47 SDHD total mutation carriers showed similar ages at diagnosis but differences in penetrance and of tumor manifestations. Head and neck paragangliomas (10/32 vs 27/34, respectively, P<.001) and multifocal (9/32 vs 25/34, respectively, P<.001) tumors were more frequent in carriers of SDHD mutations. In contrast, SDHB mutation carriers have an increased frequency of malignant disease (11/32 vs 0/34, P<.001). Renal cell cancer was observed in 2 SDHB mutation carriers and papillary thyroid cancer in 1 SDHB mutation carrier and 1 SDHD mutation carrier. CONCLUSIONS: In contrast with SDHD mutation carriers (PGL-1) who have more frequent multifocal paragangliomas, SDHB mutation carriers (PGL-4) are more likely to develop malignant disease and possibly extraparaganglial neoplasias, including renal cell and thyroid carcinomas. Appropriate and timely clinical screening is recommended in all patients with PGL-1 and PGL-4.

Early-onset renal cell carcinoma as a novel extraparaganglial component of SDHB-associated heritable paraganglioma.

Hereditary paraganglioma syndrome has recently been shown to be caused by germline heterozygous mutations in three (SDHB, SDHC, and SDHD) of the four genes that encode mitochondrial succinate dehydrogenase. Extraparaganglial component neoplasias have never been previously documented. In a population-based registry of symptomatic presentations of phaeochromocytoma/paraganglioma comprising 352 registrants, among whom 16 unrelated registrants were SDHB mutation positive, one family with germline SDHB mutation c.847-50delTCTC had two members with renal cell carcinoma (RCC), of solid histology, at ages 24 and 26 years. Both also had paraganglioma. A registry of early-onset RCCs revealed a family comprising a son with clear-cell RCC and his mother with a cardiac tumor, both with the germline SDHB R27X mutation. The cardiac tumor proved to be a paraganglioma. All RCCs showed loss of the remaining wild-type allele. Our observations suggest that germline SDHB mutations can predispose to early-onset kidney cancers in addition to paragangliomas and carry implications for medical surveillance.