Pathogenic role and diagnostic utility of interferon-α in histiocytic necrotizing lymphadenitis.

PURPOSE: Histiocytic necrotizing lymphadenitis (HNL) is an inflammatory disease of unknown etiology clinically characterized by painful lymphadenopathy. This study aimed to investigate the role of interferon (IFN)-α in the pathogenesis of HNL and the clinical significance of serum IFN-α levels for the diagnosis and monitoring of HNL disease activity. METHODS: This study enrolled 47 patients with HNL and 43 patients with other inflammatory diseases that require HNL differentiation including malignant lymphoma (ML), bacterial lymphadenitis, and Kawasaki disease. Expression of IFN-stimulated genes (ISGs) and MX1 in the lymph nodes was measured by real-time quantitative reverse transcription polymerase chain reaction and immunofluorescence staining, respectively. Enzyme-linked immunosorbent assay was used to quantify serum cytokine levels. The results were compared with the clinical features and disease course of HNL. RESULTS: Patients with HNL had a significantly elevated ISG expression in the lymph nodes compared with those with ML. MX1 and CD123, a specific marker of plasmacytoid dendritic cells (pDCs), were colocalized. In patients with HNL, serum IFN-α levels were significantly elevated and positively correlated with disease activity. The serum IFN-α level cutoff value for differentiating HNL from other diseases was 11.5 pg/mL. CONCLUSION: IFN-α overproduction from pDCs may play a critical role in HNL pathogenesis. The serum IFN-α level may be a valuable biomarker for the diagnosis and monitoring of disease activity in patients with HNL.

A case of primary ciliary dyskinesis with DRC1 deletion and literature review: Additional evidence on the founder effect.

BACKGROUND: Primary ciliary dyskinesia (PCD) is a rare genetic disease caused by defects in various genes affecting ciliary function. It is currently unclear why DRC1 gene variants are a relatively frequent cause of disease in Japanese and Korean patients. METHODS: A 12-year-old Japanese girl with bronchiectasis was suspected of PCD and examined using whole-exome sequencing (WES). The breakpoint region was confirmed by Sanger sequencing and evaluation of transposable elements. RESULTS: Whole-exome sequencing revealed a deletion of DRC1 exons 1-4 in the patient, followed by validation with Sanger sequencing. A DRC1 exon 1-4 deletion is recurrently observed in Japanese and Korean patients with PCD. All reported patients carry the same breakpoint region, which shows signs of Alu-mediated recombination. Intriguingly, common haplotypes were observed around the DRC1 gene in Japanese and Korean patients. CONCLUSION: The recurrent DRC1 exon 1-4 deletion is therefore likely to be a founder variant and should be considered a major genetic cause of PCD in Japanese and Korean patients with PCD.

Genetic and clinical landscape of childhood cerebellar hypoplasia and atrophy.

PURPOSE: Cerebellar hypoplasia and atrophy (CBHA) in children is an extremely heterogeneous group of disorders, but few comprehensive genetic studies have been reported. Comprehensive genetic analysis of CBHA patients may help differentiating atrophy and hypoplasia and potentially improve their prognostic aspects. METHODS: Patients with CBHA in 176 families were genetically examined using exome sequencing. Patients with disease-causing variants were clinically evaluated. RESULTS: Disease-causing variants were identified in 96 of the 176 families (54.5%). After excluding 6 families, 48 patients from 42 families were categorized as having syndromic associations with CBHA, whereas the remaining 51 patients from 48 families had isolated CBHA. In 51 patients, 26 aberrant genes were identified, of which, 20 (76.9%) caused disease in 1 family each. The most prevalent genes were CACNA1A, ITPR1, and KIF1A. Of the 26 aberrant genes, 21 and 1 were functionally annotated to atrophy and hypoplasia, respectively. CBHA+S was more clinically severe than CBHA-S. Notably, ARG1 and FOLR1 variants were identified in 2 families, leading to medical treatments. CONCLUSION: A wide genetic and clinical diversity of CBHA was revealed through exome sequencing in this cohort, which highlights the importance of comprehensive genetic analyses. Furthermore, molecular-based treatment was available for 2 families.

Valine-restricted diet for patients with ECHS1 deficiency: Divergent clinical outcomes in two Japanese siblings.

BACKGROUND: ECHS1 is a key enzyme of the valine catabolic pathway and oxidation of fatty acids. In ECHS1 deficiency (ECHS1D), accumulation of toxic intermediates from the valine induces neurodegeneration, which presents Leigh syndrome (LS). Therefore, valine restriction is suggested as an effective therapy. Further, cysteamine may detoxify the toxic metabolites themselves and N-acetylcysteine (NAC) is a potent antioxidant preventing neurological affect. Herein, we report the therapeutic effects of dietary therapy, cysteamine, and NAC in two siblings with ECHS1D, including their clinical, neuroradiological, and chemical aspects. CASE REPORT: The elder sister was the proband and was diagnosed as LS at 13 months of age. Gene analysis identified compound heterozygous ECHS1 mutations. Her psychomotor development was regressed, and she became bedridden. At 4 years old she started a low protein diet (LPD), but with no obvious neurological change. The younger brother was confirmed early with ECHS1D and received cysteamine and NAC treatment from 5 months of age, which could not prevent him developing LS at 7 months of age. Thus, we started a LPD at 14 months of age, with which he regained his ability to roll over, then we proceeded to a valine-restricted diet. The brain magnetic resonance image hyperintensity was diminished, and the lactate peak on magnetic resonance spectroscopy decreased. His neurological outcome is better than his elder sister. In both cases, excretion of valine metabolites decreased after dietary therapy without obvious adverse effects. CONCLUSION: Early initiation of dietary therapy may reduce neurological sequelae in patients with ECHS1D.

Association of early-onset epileptic encephalopathy with involuntary movements - Case series and literature review.

Epileptic-dyskinetic encephalopathies are rare epilepsies characterized by early-onset epileptic encephalopathies (EOEEs) with involuntary movement. Herein, we investigated the impact of gene variants in epileptic-dyskinetic encephalopathies. Four independent patients from four families who exhibited involuntary movements were recruited from Tokyo Metropolitan Neurological Hospital. The inclusion criteria were as follows: onset within 1 year after birth, frequent seizures, severe developmental delay and accompanying involuntary movements. We detected four genetic mutations, including STXBP1, GNAO1, CYFIP2, and SCN8A variants. The involuntary movements were drug-resistant. However, pallidal electrocoagulation followed by gabapentin were partially effective in treating chorea and ballismus of the extremities in patients with GNAO1 variants, and perampanel partially suppressed seizures and involuntary movements in one patient with a SCN8A variant. Movement disorders are common to many neurodevelopmental disorders, including a variety of EOEEs. Although we could not establish a definitive correlation using genetic variants in patients with EOEE and movement disorders, involuntary movements in patients with EOEEs may be a key diagnostic finding. The usage of genetic variants could prove beneficial in the future as more patients are investigated with epileptic-dyskinetic encephalopathies.

IVIG in childhood primary angiitis of the central nervous system: A case report.

Aggressive immunosuppressive therapies have been proposed to treat primary angiitis of the central nervous system (PACNS). Here, we report the first successfully stabilized case of childhood, small-vessel PACNS with intravenous immunoglobulin (IVIG) therapy. A 12-year-old boy was admitted to our hospital complaining of recurrent headaches and upper-left homonymous quadrantanopia, since the age of 11 years. Brain computed tomography scans revealed fine calcification in the right temporal and occipital lobes. Brain magnetic resonance imaging scans revealed white matter lesions, with gadolinium enhancement, which waxed, waned, and migrated for 1 year, without immunomodulatory therapies. A cerebrospinal fluid study showed pleocytosis (12 cells per µl). No clinical or serological findings suggested systemic inflammation or vasculitis. Brain angiography was unremarkable. Brain biopsy revealed thickened and hyalinized small vessels, with intramural infiltration of inflammatory cells, which confirmed the diagnosis of small-vessel PACNS. Because the patient developed surgical site infection following biopsy, the administration of monthly IVIG (2 g/kg) was prescribed, instead of immunosuppressive agents. After IVIG therapy, the patient remained stable, except for a single episode of mild radiological exacerbation at 16 months, which occurred when the IVIG interval was expanded. Oral prednisone was added and gradually tapered. At 50 months, his intellectual abilities and motor functions were normal, although he showed residual upper-left homonymous quadrantanopia and post-exercise headache. A temporary headache, associated with the immunoglobulin infusion, was resolved by slowing the infusion rate. PACNS should be treated aggressively to improve prognosis. However, when immunosuppressants are contraindicated, IVIG may be an alternative therapeutic option.

A novel splicing mutation in SLC9A6 in a boy with Christianson syndrome.

A loss of function mutation in SLC9A6 (Xq26.3) is responsible for Christianson syndrome in males. We identified a novel splicing mutation (NM_006359.2:c.1141-8C>A) of SLC9A6 in a seven-year-old boy with microcephaly, severe developmental delay, and intractable epilepsy. Functional analysis found multiple aberrant transcripts, none of which maintained the canonical open reading frame. Computer prediction tools, however, failed to detect all of the aberrant transcripts.