Norwegian patients with APS I clinically resemble those from Finland and other European countries, but some have milder phenotypes. In total, six new mutations were identified in the Norwegian APS I patients. Anti-type I IFN autoantibodies are easily detectable; their APS I specificity and persistently high titers render them reliable markers of APS I, even in prodromal or atypical cases. Both the clinical features and the AIRE mutations are more diverse in the Norwegian population than previously thought.

Objective:The epidemiology of hypoparathyroidism (HP) is largely unknown. We aimed to determine prevalence, etiologies, health related quality of life (HRQOL) and treatment pattern of HP.Methods:Patients with HP and 22q11 deletion syndrome (DiGeorge syndrome) were identified in electronic hospital registries. All identified patients were invited to participate in a survey. Among patients who responded, HRQOL was determined by Short Form 36 and Hospital Anxiety and Depression scale. Autoantibodies were measured and candidate genes (CaSR, AIRE, GATA3, and 22q11-deletion) were sequenced for classification of etiology.Results:We identified 522 patients (511 alive) and estimated overall prevalence at 102 per million divided among postsurgical HP (64 per million), nonsurgical HP (30 per million), and pseudo-HP (8 per million). Nonsurgical HP comprised autosomal dominant hypocalcemia (21%), autoimmune polyendocrine syndrome type 1 (17%), DiGeorge/22q11 deletion syndrome (15%), idiopathic HP (44%), and others (4%). Among the 283 respondents (median age, 53 years [range, 9–89], 75% females), seven formerly classified as idiopathic were reclassified after genetic and immunological analyses, whereas 26 (37% of nonsurgical HP) remained idiopathic. Most were treated with vitamin D (94%) and calcium (70%), and 10 received PTH. HP patients scored significantly worse than the normative population on Short Form 36 and Hospital Anxiety and Depression scale; patients with postsurgical scored worse than those with nonsurgical HP and pseudo-HP, especially on physical health.Conclusions:We found higher prevalence of nonsurgical HP in Norway than reported elsewhere. Genetic testing and autoimmunity screening of idiopathic HP identified a specific cause in 21%. Further research is necessary to unravel the causes of idiopathic HP and to improve the reduced HRQOL reported by HP patients.

Context:Autoimmune polyendocrine syndrome type 1 (APS1) is a childhood-onset monogenic disease defined by the presence of two of the three major components: hypoparathyroidism, primary adrenocortical insufficiency, and chronic mucocutaneous candidiasis (CMC). Information on longitudinal follow-up of APS1 is sparse.Objective:To describe the phenotypes of APS1 and correlate the clinical features with autoantibody profiles and autoimmune regulator (AIRE) mutations during extended follow-up (1996–2016).Patients:All known Norwegian patients with APS1.Results:Fifty-two patients from 34 families were identified. The majority presented with one of the major disease components during childhood. Enamel hypoplasia, hypoparathyroidism, and CMC were the most frequent components. With age, most patients presented three to five disease manifestations, although some had milder phenotypes diagnosed in adulthood. Fifteen of the patients died during follow-up (median age at death, 34 years) or were deceased siblings with a high probability of undisclosed APS1. All except three had interferon-ω) autoantibodies, and all had organ-specific autoantibodies. The most common AIRE mutation was c.967_979del13, found in homozygosity in 15 patients. A mild phenotype was associated with the splice mutation c.879+1G>A. Primary adrenocortical insufficiency and type 1 diabetes were associated with protective human leucocyte antigen genotypes.Conclusions:Multiple presumable autoimmune manifestations, in particular hypoparathyroidism, CMC, and enamel hypoplasia, should prompt further diagnostic workup using autoantibody analyses (eg, interferon-ω) and AIRE sequencing to reveal APS1, even in adults. Treatment is complicated, and mortality is high. Structured follow-up should be performed in a specialized center.

Neutralizing autoantibodies to type I, but not type II, interferons (IFNs) are found at high titers in almost every patient with autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED), a disease caused by AIRE gene mutations that lead to defects in thymic T-cell selection. Combining genome-wide expression array with real time RT-PCR assays, we here demonstrate that antibodies against IFN-α cause highly significant down-regulation of interferon-stimulated gene expression in cells from APECED patients' blood by blocking their highly dilute endogenous IFNs. This down-regulation was lost progressively as these APECED cells matured in cultures without neutralizing autoantibodies. Most interestingly, a rare APECED patient with autoantibodies to IFN-ω but not IFN-α showed a marked increase in expression of the same interferon-stimulated genes. We also report unexpected increases in serum CXCL10 levels in APECED. Our results argue that the breakdown of tolerance to IFNs in AIRE deficiency is associated with impaired responses to them in thymus, and highlight APECED as another autoimmune disease with associated dysregulation of IFN activity.

ContextGenetic testing for monogenic diabetes is important for patient care. Given the extensive genetic and clinical heterogeneity of diabetes, exome sequencing might provide additional diagnostic potential when standard Sanger sequencing-based diagnostics is inconclusive.ObjectiveThe aim of the study was to examine the performance of exome sequencing for a molecular diagnosis of MODY in patients who have undergone conventional diagnostic sequencing of candidate genes with negative results.Research Design and MethodsWe performed exome enrichment followed by high-throughput sequencing in nine patients with suspected MODY. They were Sanger sequencing-negative for mutations in the HNF1A, HNF4A, GCK, HNF1B and INS genes. We excluded common, non-coding and synonymous gene variants, and performed in-depth analysis on filtered sequence variants in a pre-defined set of 111 genes implicated in glucose metabolism.ResultsOn average, we obtained 45 X median coverage of the entire targeted exome and found 199 rare coding variants per individual. We identified 0–4 rare non-synonymous and nonsense variants per individual in our a priori list of 111 candidate genes. Three of the variants were considered pathogenic (in ABCC8, HNF4A and PPARG, respectively), thus exome sequencing led to a genetic diagnosis in at least three of the nine patients. Approximately 91% of known heterozygous SNPs in the target exomes were detected, but we also found low coverage in some key diabetes genes using our current exome sequencing approach. Novel variants in the genes ARAP1, GLIS3, MADD, NOTCH2 and WFS1 need further investigation to reveal their possible role in diabetes.ConclusionOur results demonstrate that exome sequencing can improve molecular diagnostics of MODY when used as a complement to Sanger sequencing. However, improvements will be needed, especially concerning coverage, before the full potential of exome sequencing can be realized.

Autoimmune polyendocrine syndrome type I (APS I) is a recessive disorder caused by mutations in the autoimmune regulator (AIRE) gene. AIRE is expressed in medullary epithelial cells where it activates transcription of organ‐specific proteins in thymus, thereby regulating autoimmunity. Patients with APS I have, in addition to autoimmune manifestations in endocrine organs, also often ectodermal dystrophies and chronic mucocutaneous candidiasis. The aim of this study was to characterize immune cell subpopulations in patients with APS I and their close relatives. Extensive blood mononuclear cell immunophenotyping was carried out on 19 patients with APS I, 18 first grade relatives and corresponding sex‐ and age‐matched healthy controls using flow cytometry. We found a significant relative reduction in T helper cells coexpressing CCR6 and CXCR3 in patients with APS I compared to controls (mean = 4.10% versus 5.94% respectively, P = 0.035). The pools of CD16+ monocytes and regulatory T cells (Tregs) were also lower in patients compared with healthy individuals (mean = 15.75% versus 26.78%, P = 0.028 and mean = 4.12% versus 6.73%, P = 0.029, respectively). This is the first report describing reduced numbers of CCR6+CXCR3+ T helper cells and CD16+ monocytes in patients with APS I We further confirm previous findings of reduced numbers of Tregs in these patients.

SummaryThymic hypoplasia is a frequent feature of the 22q11.2 deletion syndrome, but we know little about patients' age-related thymic output and long-term consequences for their immune system. We measured the expression of T cell receptor rearrangement excision circles (TREC) and used flow cytometry for direct subtyping of recent thymic emigrant (RTE)-related T cells in 43 patients (aged 1-54 years; median 9 years) from all over Norway and in age-matched healthy controls. Thymic volumes were estimated by ultrasound in patients. TREC levels correlated well with RTE-related T cells defined by co-expression of CD3, CD45RA and CCR9 (r = 0·84) as well as with the CD4 + and CD8+ T cell subtypes. RTE-related T cell counts also paralleled age-related TREC reductions. CD45RA+ T cells correlated well with absolute counts of CD4 + (r = 0·87) and CD8 + (r = 0·75) RTE-related T cells. Apart from CD45RA-T cells, all T cell subsets were lower in patients than in controls. Thymic volumes correlated better with RTE-related cells (r = 0·46) than with TREC levels (r = 0·38). RTE-related T cells and TREC levels also correlated well (r = 0·88) in patients without an identifiable thymus. Production of RTEs is impaired in patients with a 22q11.2 deletion, and CCR9 appears to be a good marker for RTE-related T cells.

Enamel disturbances were frequently seen. There were more hypomineralizations than hypoplasias. Hypoparathyroidism and/or hypocalcemia are not clear etiological factors for enamel disturbances and there were no major correlations between medical conditions and enamel disturbances.