Expanded Newborn Screening Using Genome Sequencing for Early Actionable Conditions.

Importance: The feasibility of implementing genome sequencing as an adjunct to traditional newborn screening (NBS) in newborns of different racial and ethnic groups is not well understood. Objective: To report interim results of acceptability, feasibility, and outcomes of an ongoing genomic NBS study in a diverse population in New York City within the context of the New York State Department of Health Newborn Screening Program. Design, Setting, and Participants: The Genomic Uniform-screening Against Rare Disease in All Newborns (GUARDIAN) study was a multisite, single-group, prospective, observational investigation of supplemental newborn genome screening with a planned enrollment of 100 000 participants. Parent-reported race and ethnicity were recorded at the time of recruitment. Results of the first 4000 newborns enrolled in 6 New York City hospitals between September 2022 and July 2023 are reported here as part of a prespecified interim analysis. Exposure: Sequencing of 156 early-onset genetic conditions with established interventions selected by the investigators were screened in all participants and 99 neurodevelopmental disorders associated with seizures were optional. Main Outcomes and Measures: The primary outcome was screen-positive rate. Additional outcomes included enrollment rate and successful completion of sequencing. Results: Over 11 months, 5555 families were approached and 4000 (72.0%) consented to participate. Enrolled participants reflected a diverse group by parent-reported race (American Indian or Alaska Native, 0.5%; Asian, 16.5%; Black, 25.1%; Native Hawaiian or Other Pacific Islander, 0.1%; White, 44.7%; 2 or more races, 13.0%) and ethnicity (Hispanic, 44.0%; not Hispanic, 56.0%). The majority of families consented to screening of both groups of conditions (both groups, 90.6%; disorders with established interventions only, 9.4%). Testing was successfully completed for 99.6% of cases. The screen-positive rate was 3.7%, including treatable conditions that are not currently included in NBS. Conclusions and Relevance: These interim findings demonstrate the feasibility of targeted interpretation of a predefined set of genes from genome sequencing in a population of different racial and ethnic groups. DNA sequencing offers an additional method to improve screening for conditions already included in NBS and to add those that cannot be readily screened because there is no biomarker currently detectable in dried blood spots. Additional studies are required to understand if these findings are generalizable to populations of different racial and ethnic groups and whether introduction of sequencing leads to changes in management and improved health outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT05990179.

Incontinentia pigmenti underlies thymic dysplasia, autoantibodies to type I IFNs, and viral diseases.

Human inborn errors of thymic T cell tolerance underlie the production of autoantibodies (auto-Abs) neutralizing type I IFNs, which predispose to severe viral diseases. We analyze 131 female patients with X-linked dominant incontinentia pigmenti (IP), heterozygous for loss-of-function (LOF) NEMO variants, from 99 kindreds in 10 countries. Forty-seven of these patients (36%) have auto-Abs neutralizing IFN-α and/or IFN-ω, a proportion 23 times higher than that for age-matched female controls. This proportion remains stable from the age of 6 years onward. On imaging, female patients with IP have a small, abnormally structured thymus. Auto-Abs against type I IFNs confer a predisposition to life-threatening viral diseases. By contrast, patients with IP lacking auto-Abs against type I IFNs are at no particular risk of viral disease. These results suggest that IP accelerates thymic involution, thereby underlying the production of auto-Abs neutralizing type I IFNs in at least a third of female patients with IP, predisposing them to life-threatening viral diseases.

Individuals with JAK1 variants are affected by syndromic features encompassing autoimmunity, atopy, colitis, and dermatitis.

Inborn errors of immunity lead to autoimmunity, inflammation, allergy, infection, and/or malignancy. Disease-causing JAK1 gain-of-function (GoF) mutations are considered exceedingly rare and have been identified in only four families. Here, we use forward and reverse genetics to identify 59 individuals harboring one of four heterozygous JAK1 variants. In vitro and ex vivo analysis of these variants revealed hyperactive baseline and cytokine-induced STAT phosphorylation and interferon-stimulated gene (ISG) levels compared with wild-type JAK1. A systematic review of electronic health records from the BioME Biobank revealed increased likelihood of clinical presentation with autoimmunity, atopy, colitis, and/or dermatitis in JAK1 variant-positive individuals. Finally, treatment of one affected patient with severe atopic dermatitis using the JAK1/JAK2-selective inhibitor, baricitinib, resulted in clinically significant improvement. These findings suggest that individually rare JAK1 GoF variants may underlie an emerging syndrome with more common presentations of autoimmune and inflammatory disease (JAACD syndrome). More broadly, individuals who present with such conditions may benefit from genetic testing for the presence of JAK1 GoF variants.

CVID-Associated Intestinal Disorders in the USIDNET Registry: An Analysis of Disease Manifestations, Functional Status, Comorbidities, and Treatment.

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

Respiratory Comorbidities Associated with Bronchiectasis in Patients with Common Variable Immunodeficiency in the USIDNET Registry.

BACKGROUND: Bronchiectasis is a major respiratory complication in patients with common variable immunodeficiency (CVID) and is associated with recurrent pulmonary infections. However, it is unclear whether other infections or non-infectious respiratory conditions are related to its development. OBJECTIVE: To identify respiratory comorbidities associated with bronchiectasis in patients with CVID. METHODS: A total of 1470 CVID patients enrolled in the USIDNET registry were included in a cross-sectional analysis. The primary outcome of our study was to determine the clinical characteristics and other respiratory conditions associated with respiratory comorbidities and physician-reported bronchiectasis. RESULTS: One hundred ninety-seven CVID patients were noted to have bronchiectasis (13.4%). Affected patients were significantly older than patients without bronchiectasis (median age 54 years vs. 49 years, p = 0.0004). These patients also had lower serum IgA (13 mg/dL IQR 60 mg/dL vs. 28.4 mg/dL IQR 66 mg/dL, p = 0.000). Notably, chronic rhinosinusitis (OR = 1.69 95%CI 1.05-2.75), sinusitis (OR = 2.06 95%CI 1.38-3.09), pneumonia (OR = 2.70 95%CI 1.88-3.88), COPD (OR = 2.66 95%CI 1.51-4.67), and interstitial lung disease (OR = 2.34 95%CI 1.41-3.91) were independently associated with the development of bronchiectasis in this population. CONCLUSION: These data suggest that lower and upper respiratory infections, chronic lower airway disease, and interstitial lung diseases are independently associated with bronchiectasis in CVID patients. Further study into predisposing conditions related to the development of bronchiectasis in CVID patients may allow prediction and early intervention strategies to prevent the development of this complication.

Who's your data? Primary immune deficiency differential diagnosis prediction via machine learning and data mining of the USIDNET registry.

PURPOSE: There are currently more than 480 primary immune deficiency (PID) diseases and about 7000 rare diseases that together afflict around 1 in every 17 humans. Computational aids based on data mining and machine learning might facilitate the diagnostic task by extracting rules from large datasets and making predictions when faced with new problem cases. In a proof-of-concept data mining study, we aimed to predict PID diagnoses using a supervised machine learning algorithm based on classification tree boosting. METHODS: Through a data query at the USIDNET registry we obtained a database of 2396 patients with common diagnoses of PID, including their clinical and laboratory features. We kept 286 features and all 12 diagnoses to include in the model. We used the XGBoost package with parallel tree boosting for the supervised classification model, and SHAP for variable importance interpretation, on Python v3.7. The patient database was split into training and testing subsets, and after boosting through gradient descent, the predictive model provides measures of diagnostic prediction accuracy and individual feature importance. After a baseline performance test, we used the Class Weighting Hyperparameter, or scale_pos_weight to correct for imbalanced classification. RESULTS: The twelve PID diagnoses were CVID (1098 patients), DiGeorge syndrome, Chronic granulomatous disease, Congenital agammaglobulinemia, PID not otherwise classified, Specific antibody deficiency, Complement deficiency, Hyper-IgM, Leukocyte adhesion deficiency, ectodermal dysplasia with immune deficiency, Severe combined immune deficiency, and Wiskott-Aldrich syndrome. For CVID, the model found an accuracy on the train sample of 0.80, with an area under the ROC curve (AUC) of 0.80, and a Gini coefficient of 0.60. In the test subset, accuracy was 0.76, AUC 0.75, and Gini 0.51. The positive feature value to predict CVID was highest for upper respiratory infections, asthma, autoimmunity and hypogammaglobulinemia. Features with the highest negative predictive value were high IgE, growth delay, abscess, lymphopenia, and congenital heart disease. For the rest of the diagnoses, accuracy stayed between 0.75 and 0.99, AUC 0.46-0.87, Gini 0.07-0.75, and LogLoss 0.09-8.55. DISCUSSION: Clinicians should remember to consider the negative predictive features together with the positives. We are calling this a proof-of-concept study to continue with our explorations. A good performance is encouraging, and feature importance might aid feature selection for future endeavors. In the meantime, we can learn from the rules derived by the model and build a user-friendly decision tree to generate differential diagnoses.

CVID-associated intestinal disorders in the USIDNET registry: An analysis of disease manifestations, functional status, comorbidities, and treatment.

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

A Registry Study of 240 Patients with X-Linked Agammaglobulinemia Living in the USA.

PURPOSE: To understand the natural history and clinical outcomes for patients with X-linked agammaglobulinemia (XLA) in the United States utilizing the United States Immunodeficiency Network (USIDNET) patient registry. METHODS: The USIDNET registry was queried for data from XLA patients collected from 1981 to 2019. Data fields included demographics, clinical features before and after diagnosis of XLA, family history, genetic mutation in Bruton's tyrosine kinase (BTK), laboratory findings, treatment modalities, and mortality. RESULTS: Data compiled through the USIDNET registry on 240 patients were analyzed. Patient year of birth ranged from 1945 to 2017. Living status was available for 178 patients; 158/178 (88.8%) were alive. Race was reported for 204 patients as follows: White, 148 (72.5%); Black/African American, 23 (11.2%); Hispanic, 20 (9.8%); Asian or Pacific Islander, 6 (2.9%), and other or more than one race, 7 (3.4%). The median age at last entry, age at disease onset, age at diagnosis, and length of time with XLA diagnosis was 15 [range (r) = 1-52 years], 0.8 [r = birth-22.3 years], 2 [r = birth-29 years], and 10 [r = 1-56 years] years respectively. One hundred and forty-one patients (58.7%) were < 18 years of age. Two hundred and twenty-one (92%) patients were receiving IgG replacement (IgGR), 58 (24%) were on prophylactic antibiotics, and 19 (7.9%) were on immunomodulatory drugs. Eighty-six (35.9%) patients had undergone surgical procedures, two had undergone hematopoietic cell transplantation, and two required liver transplantation. The respiratory tract was the most affected organ system (51.2% of patients) followed by gastrointestinal (40%), neurological (35.4%), and musculoskeletal (28.3%). Infections were common both before and after diagnosis, despite IgGR therapy. Bacteremia/sepsis and meningitis were reported more frequently before XLA diagnosis while encephalitis was more commonly reported after diagnosis. Twenty patients had died (11.2%). The median age of death was 21 years (range = 3-56.7 years). Neurologic condition was the most common underlying co-morbidity for those XLA patients who died. CONCLUSIONS: Current therapies for XLA patients reduce early mortality, but patients continue to experience complications that impact organ function. With improved life expectancy, more efforts will be required to improve post-diagnosis organ dysfunction and quality of life. Neurologic manifestations are an important co-morbidity associated with mortality and not yet clearly fully understood.

Eosinophilic gastrointestinal disorders in patients with inborn errors of immunity: Data from the USIDNET registry.

Rationale: Eosinophilic gastrointestinal disorders (EGID), including eosinophilic esophagitis (EoE), are inflammatory disorders of the gastrointestinal mucosa mediated by complex immune mechanisms. Although there have been initial reports of EGID in patients with inborn errors of immunity (IEI), little is known about the presentation of EGID in immunodeficient individuals. Methods: We queried the U.S. Immunodeficiency Network (USIDNET) for patient records including the terms eosinophilic esophagitis, gastritis, enteritis, or colitis. We analyzed 74 patient records from the database, including diagnoses, demographics, infectious history, laboratory findings, genetic studies, therapeutic interventions, and clinical outcomes. Results: We examined 74 patient records. A total of 61 patients had isolated EoE, and 13 had distal gastrointestinal involvement consistent with EGID. The most common IEI were common variable immunodeficiency (43.2%), some form of combined immunodeficiency (21.6%), chronic granulomatous disease (8.1%), hyper-IgE syndrome (6.8%), and autoimmune lymphoproliferative syndrome (6.8%). The median age at presentation with IEI was 0.5 years (IQR 1.725, max 39 years) and 56.76% were male. Approximately 20% of the patients in the cohort received a hematopoietic stem cell transplantation for treatment of IEI, but the timing of the HSCT in relationship to the EGID diagnosis was unknown. Conclusions: Here, we report EGID in a diverse cohort of IEI patients, suggesting that both non-EoE EGID and EoE can be seen as comorbid conditions with a variety of IEI. Our data suggests that EGID may be more common in patients with IEI than would be expected based on estimates of EGID in the general population.

Risk Factors of Pneumonia in Primary Antibody Deficiency Patients Receiving Immunoglobulin Therapy: Data from the US Immunodeficiency Network (USIDNET).

BACKGROUND: Despite immunoglobulin replacement (IgRT) therapy, some patients with primary antibody deficiency (PAD) continue to develop respiratory infections. Recurrent and severe respiratory infections, particularly pneumonia, can lead to significant morbidity and mortality. Therefore, we sought to determine the risk factors of developing pneumonia in PAD patients, already receiving IgRT. METHODS: We evaluated clinical and laboratory features of PAD patients enrolled in the US Immune Deficiency Network (USIDNET) registry by April 2017. Patients were included if they met the following criteria: (1) PAD diagnosis (common variable immunodeficiency (CVID), agammaglobulinemia, hypogammaglobinemia, and specific antibody deficiency (SAD) and (2) available data on infections before and after IgRT. Patients were excluded if they were not receiving IgRT, or if no pre/post infections data were available. Descriptive and multivariable logistic regression analyses were used to identify factors associated with pneumonia post-IgRT. RESULTS: A total of 1232 patients met the inclusion criteria. Following IgRT, 218 patients (17.7%) were reported to have at least one pneumonia episode. Using multivariate logistic regression analysis, we found a statistically significant increased risk of pneumonia in patients with asthma (OR: 2.55, 95% CI (1.69-3.85), p < 0.001) bronchiectasis (OR: 3.94, 95% CI (2.29-6.80), p < 0.001), interstitial lung disease (ILD) (OR: 3.28, 95%CI (1.43-7.56), p < 0.005), splenomegaly (OR: 2.02, 95%CI (1.08-3.76), p < 0.027), allergies (OR: 2.44, 95% CI [1.44-4.13], p = 0.001), and patients who were not on immunosuppressives (OR: 1.61; 95%CI [1.06-2.46]; p = 0.027). For every 50 unit increase in IgA, the odds of reporting pneumonia post IgRT decreased (OR: 0.86, 95% CI [0.73-1.02], p = 0.062). Infectious organisms were reported in 35 of 218 patients who reported pneumonia after IgRT. Haemophilus influenzae was the most frequently reported (n = 11, 31.43%), followed by Streptococcus pneumoniae (n = 7, 20.00%). CONCLUSION: Our findings suggest PAD patients with chronic and structural lung disease, splenomegaly, and allergies were associated with persistent pneumonia. However, our study is limited by the cross-sectional nature of the USIDNET database and limited longitudinal data. Further studies are warranted to identify susceptible causes and explore targeted solutions for prevention and associated morbidity and mortality. CLINICAL IMPLICATIONS: Patients with primary antibody deficiency with structural lung disease, allergies, and splenomegaly are associated with persistent pneumonia post-IgRT.

Ocular Manifestations in Primary Immunodeficiency Disorders: A Report From the United States Immunodeficiency Network (USIDNET) Registry.

BACKGROUND: Few published studies address eye disease in primary immunodeficiency (PID) despite ocular infections and autoimmune disease being known manifestations of immunodeficient states. OBJECTIVE: Data from the USIDNET Registry provide a resource to study ocular ailments in subjects with PID. METHODS: Ocular manifestations and patient characteristics were determined using data from 4624 patients with PID enrolled in the US Immunodeficiency Network (USIDNET) Registry. RESULTS: A total of 519 (11.2%) patients had recorded ocular diseases. Those with autoinflammatory disorders (n = 4 of 7 [57.1%]), intrinsic and innate immunity defects (n = 9 of 44 [20.5%]), and immune dysregulation (n = 27 of 142 [19.0%]) had the highest percentage of ocular diseases for the PID diagnosis category. Of the 67.6% with infections, 85.5% had conjunctivitis. Bacteria (56.2%) and viruses (27.4%) were the most common microorganisms reported, with Staphylococcus (31.7%), Haemophilus (26.8%), and Streptococcus (22.0%) being the most common bacteria isolated. Those with a history of eye infections had lower immunoglobulin levels, lower CD19 B-cell percentages, and a lower number of protective pneumococcal titers. In patients with noninfectious ocular complications, 30.8% had vision changes, with retina (n = 20 [8.0%]), cataract (n = 16 [6.4%]), and nerve diseases (n = 16 [6.4%]) also being common. Many patients with ocular disease had serious sequelae, with 12.7% undergoing eye surgery and 10.6% having a vision-based disability. CONCLUSIONS: Vision loss and conjunctivitis were the most commonly reported ocular complications and pose large quality-of-life issues. Learning more about ocular disease in PID will increase awareness about the importance of addressing and evaluating for these ailments.

X-Linked Agammaglobulinemia: Infection Frequency and Infection-Related Mortality in the USIDNET Registry.

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disorder caused by mutations in the Bruton tyrosine kinase (BTK) gene leading to B lymphocyte deficiency and susceptibility to infection. A potential benefit of earlier diagnosis and treatment initiation on morbidity and mortality in XLA is incompletely understood. In the USIDNET Registry, we describe infection frequency and infection-related mortality in patients with XLA and their relationship to age of diagnosis and treatment initiation. Among the 231 XLA patients enrolled in the Registry, respiratory infections (N = 203, 88%) were the most commonly reported. Among those deceased (N = 20) where cause of death was known (N = 17), mortality was attributed to infection in most (N = 12, 71%). Chronic lung disease, often a consequence of repeated lower respiratory tract infection (LRTI), was also a frequent complication associated with mortality (N = 9, 53%). Age of diagnosis in years was lower for those without LRTI compared to those with (median 1.5 [IQR 0.5-3.3] vs. median 3.0 [IQR 1.0-5.0], p = 0.0026) and among living patients compared to deceased (median 1.8 [IQR 0.5-5.0] vs. median 2.7 [IQR 1.6-6.0], p = 0.04). Age at treatment initiation in years was lower among those without LRTIs compared to those with (median 1.0 [IQR 0.4-2.4] vs. median 2.8 [IQR 1.0-5.4], p = 0.0006). For every year increase in age at start of therapy, the odds of experiencing a LRTI was 1.216 (OR 1.216, 95% CI 1.048-1.411, p = 0.01). Given the expected finding of reduced LRTIs and mortality among those with earlier age at diagnosis, our study findings support inclusion of XLA in newborn screening programs.

Chronic Granulomatous Disease With Inflammatory Bowel Disease: Clinical Presentation, Treatment, and Outcomes From the USIDNET Registry.

BACKGROUND: Chronic granulomatous disease (CGD) is an inborn error of immunity caused by defects in the phagocytic nicotinamide adenine dinucleotide phosphate oxidase complex, leading to increased susceptibility to infection and inflammatory autoimmune diseases. Up to 50% of patients have gastrointestinal (GI) involvement and meet diagnostic criteria for inflammatory bowel disease (CGD-IBD). OBJECTIVE: We analyzed patients with CGD from the US Immunodeficiency Network (USIDNET) registry to determine whether IBD changes the presentation, treatment, and outcomes of patients with CGD. METHODS: A retrospective evaluation of CGD cases from the USIDNET registry was completed. CGD-IBD was defined as the presence of any major physician-reported inflammatory, noninfectious GI disease manifestation. Demographic information, conditions, infections, antimicrobial therapies, immunomodulator use, and hematopoietic stem cell transplantation data were analyzed. RESULTS: Of 194 patients with a diagnosis of CGD, 96 met criteria for IBD and 98 were categorized in the non-IBD group. Patients with CGD-IBD had an increased rate of infection compared with the non-IBD group (0.66 vs 0.36 infections/patient/year). Enteric organism infections were more common in patients with IBD. Immunomodulators were used at a significantly higher percentage in patients with IBD compared with patients without IBD (80% vs 56%, P < .001). Of the entire CGD cohort, 17 patients died (8.8%), with no significant difference between patients with IBD and patients without IBD (P = 1.00). CONCLUSION: Infectious events, enteric organism infections, and use of immunomodulatory drugs were higher in patients with IBD than patients without IBD; however, mortality was not increased. Patients with CGD and concurrent IBD are at increased risk for disease complications, supporting the importance of early recognition, diagnosis, and treatment.

Neuropathological and biochemical investigation of Hereditary Ferritinopathy cases with ferritin light chain mutation: Prominent protein aggregation in the absence of major mitochondrial or oxidative stress.

AIMS: Neuroferritinopathy (NF) or hereditary ferritinopathy (HF) is an autosomal dominant movement disorder due to mutation in the light chain of the iron storage protein ferritin (FTL). HF is the only late-onset neurodegeneration with brain iron accumulation disorder and study of HF offers a unique opportunity to understand the role of iron in more common neurodegenerative syndromes. METHODS: We carried out pathological and biochemical studies of six individuals with the same pathogenic FTL mutation. RESULTS: CNS pathological changes were most prominent in the basal ganglia and cerebellar dentate, echoing the normal pattern of brain iron accumulation. Accumulation of ferritin and iron was conspicuous in cells with a phenotype suggesting oligodendrocytes, with accompanying neuronal pathology and neuronal loss. Neurons still survived, however, despite extensive adjacent glial iron deposition, suggesting neuronal loss is a downstream event. Typical age-related neurodegenerative pathology was not normally present. Uniquely, the extensive aggregates of ubiquitinated ferritin identified indicate that abnormal FTL can aggregate, reflecting the intrinsic ability of FTL to self-assemble. Ferritin aggregates were seen in neuronal and glial nuclei showing parallels with Huntington's disease. There was neither evidence of oxidative stress activation nor any significant mitochondrial pathology in the affected basal ganglia. CONCLUSIONS: HF shows hallmarks of a protein aggregation disorder, in addition to iron accumulation. Degeneration in HF is not accompanied by age-related neurodegenerative pathology and the lack of evidence of oxidative stress and mitochondrial damage suggests that these are not key mediators of neurodegeneration in HF, casting light on other neurodegenerative diseases characterized by iron deposition.

Infection Phenotypes Among Patients with Primary Antibody Deficiency Mined from a US Patient Registry.

PURPOSE: Primary immunodeficiency disorders (PIDs) affect immune system development and/or function, increase infection susceptibility, and cause dysregulation or both. Recognition of PID requires assessment about the normal state of infection frequency and microbiology. To help clarify infection characteristics, we use data mined from the US Immunodeficiency Network (USIDNET) registry among primary antibody deficiency (PAD) patients before diagnosis. METHODS: We analyzed PAD patient data from the USIDNET registry prior to ultimate diagnosis. Our analysis included basic descriptive statistics for 8 major infection subtypes and significance testing for comparing infection rate by specific organisms across 7 distinct PAD subtypes. RESULTS: Of 2038 patients reviewed, 1259 (61.8%) had infections reported prior to diagnosis. Most (77.4%) had four or less reported infections prior to diagnosis; however, some suffered up to 16 infections. Infection patterns differed across the PAD subtypes. Patients with agammaglobulinemia differed significantly from patients with all other forms of PAD studied in at least one infection category, whereas patients with CVID differed from 3 other PAD categories in at least one infection category. Patterns of infections in patients with hypogammaglobulinemia, specific antibody deficiency, and transient hypogammaglobulinemia were less unique. For each of the infection types, bacteria were the most prevalent cause of disease. CONCLUSIONS: Our data shows that distinct subtypes of PAD display unique infection patterns. We also show that patients with agammaglobulinemia suffer more invasive infections and differ most significantly from all other forms of PAD studied. Our analysis has broad implications about infection surveillance, progression, and vulnerability by PAD subtype.