Hironobu Kobayashi

A genome-wide association study identifies three new risk loci for Kawasaki disease

We performed a genome-wide association study (GWAS) of Kawasaki disease in Japanese subjects using data from 428 individuals with Kawasaki disease (cases) and 3,379 controls genotyped at 473,803 SNPs. We validated the association results in two independent replication panels totaling 754 cases and 947 controls. We observed significant associations in the FAM167A-BLK region at 8p22-23 (rs2254546, P = 8.2 × 10−21), in the human leukocyte antigen (HLA) region at 6p21.3 (rs2857151, P = 4.6 × 10−11) and in the CD40 region at 20q13 (rs4813003, P = 4.8 × 10−8). We also replicated the association of a functional SNP of FCGR2A (rs1801274, P = 1.6 × 10−6) identified in a recently reported GWAS of Kawasaki disease. Our findings provide new insights into the pathogenesis and pathophysiology of Kawasaki disease.

ITPKC and CASP3 polymorphisms and risks for IVIG unresponsiveness and coronary artery lesion formation in Kawasaki disease

Functional single-nucleotide polymorphisms (SNPs) in inositol 1,4,5-trisphosphate 3-kinase C (ITPKC) (rs28493229) and caspase-3 (CASP3) (rs113420705; formerly rs72689236) are associated with susceptibility to Kawasakis disease (KD). To evaluate the involvement of these 2 SNPs in the risk for intravenous immunoglobulin (IVIG) unresponsiveness, we investigated 204 Japanese KD patients who received a single IVIG dose of 2 g kg−1 (n=70) or 1 g kg−1 daily for 2 days (n=134). The susceptibility allele of both SNPs showed a trend of overrepresentation in IVIG non-responders and, in combined analysis of these SNPs, patients with at least 1 susceptible allele at both loci had a higher risk for IVIG unresponsiveness (P=0.0014). In 335 prospectively collected KD patients who were treated with IVIG (2 g kg−1), this 2-locus model showed a more significant association with resistance to initial and additional IVIG (P=0.011) compared with individual SNPs. We observed a significant association when all KD patients with coronary artery lesions were analyzed with the 2-locus model (P=0.0031). Our findings strongly suggest the existence of genetic factors affecting patients’ responses to treatment and the risk for cardiac complications, and provide clues toward understanding the pathophysiology of KD inflammation.

Variations in ORAI1 Gene Associated with Kawasaki Disease

Kawasaki disease (KD; MIM#61175) is a systemic vasculitis syndrome with unknown etiology which predominantly affects infants and children. Recent findings of susceptibility genes for KD suggest possible involvement of the Ca(2+)/NFAT pathway in the pathogenesis of KD. ORAI1 is a Ca(2+) release activated Ca(2+) (CRAC) channel mediating store-operated Ca(2+) entry (SOCE) on the plasma membrane. The gene for ORAI1 is located in chromosome 12q24 where a positive linkage signal was observed in our previous affected sib-pair study of KD. A common non-synonymous single nucleotide polymorphism located within exon 2 of ORAI1 (rs3741596) was significantly associated with KD (P = 0.028 in the discovery sample set (729 KD cases and 1,315 controls), P = 0.0056 in the replication sample set (1,813 KD cases vs. 1,097 controls) and P = 0.00041 in a meta-analysis by the Mantel-Haenszel method). Interestingly, frequency of the risk allele of rs3741596 is more than 20 times higher in Japanese compared to Europeans. We also found a rare 6 base-pair in-frame insertion variant associated with KD (rs141919534; 2,544 KD cases vs. 2,414 controls, P = 0.012). These data indicate that ORAI1 gene variations are associated with KD and may suggest the potential importance of the Ca(2+)/NFAT pathway in the pathogenesis of this disorder.

Association of NOD2 Mutations with Aggressive Periodontitis

Aggressive periodontitis (AgP) is characterized by rapid alveolar bone destruction and tooth loss early in life, and its etiology remains unclear. To explore the genetic risk factors of AgP, we performed genome-wide single-nucleotide polymorphism genotyping for identity-by-descent mapping and identified 32 distinct candidate loci, followed by whole exome sequencing with 2 pedigrees of AgP consisting of 3 cases and 1 control in 1 family and 2 sibling cases in the other. After variant filtering procedures and validation by targeted Sanger sequencing, we identified 2 missense mutations at 16q12 in NOD2 (p.Ala110Thr and p.Arg311Trp), which encodes nucleotide-binding oligomerization domain protein 2. We further examined 94 genetically unrelated AgP patients by targeted sequencing of NOD2 and found that 2 patients among them also carried the p.Arg311Trp variant. Furthermore, we found 3 additional missense mutations in this gene (p.His370Tyr, p.Arg459Cys, and p.Ala868Thr). These mutations either had not been previously observed or are extremely rare (frequency <0.001) in Asian populations. NOD2 plays a crucial role in innate immunity as an intracellular receptor initiating nuclear factor κB–dependent and mitogen-activated protein kinase–dependent gene transcription. These results demonstrated NOD2 as a novel gene involved in AgP.

Propylthiouracil-induced anti-neutrophil cytoplasmic antibody-associated vasculitis mimicking Kawasaki disease

Abstract Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is rare in children and is characterised as necrotising vasculitis predominantly affecting small and medium-sized vessels. Propylthiouracil (PTU), an antithyroid drug, has been implicated in drug-induced AAV. In contrast, Kawasaki disease (KD) is a common systemic vasculitis, typically observed in children, which affects the medium-sized vessels, including the coronary arteries. An 11-year-old girl who developed AAV while receiving PTU therapy for Graves’ disease is described. She was admitted to hospital following a 2-day history of fever, cervical adenopathy, cheilitis and papular rash, 3 weeks after an increase in the PTU dose. Despite discontinuation of PTU and the administration of intravenous antibiotic therapy, her clinical condition deteriorated and over the next 2 days she developed severe diarrhoea, conjunctival injection and swelling and redness of the right index finger. Additional findings included liver dysfunction, hydrops of the gallbladder, coagulopathy and urine abnormalities, suggesting glomerulonephritis. She met the diagnostic criteria for KD and received intravenous immunoglobulin (IVIG) combined with prednisolone, with rapid resolution of clinical and laboratory parameters. Peeling of the right index fingertip became evident on Day 12 of admission. Serial ultrasound cardiography demonstrated no evidence of cardiac involvement. A high titre of myeloperoxidase ANCA was detected in the patient’s serum on admission, and the titre decreased during the convalescent stage. This case demonstrates that children with PTU-associated AAV may present with clinical features mimicking KD, and that IVIG along with corticosteroid therapy may be effective in treating patients with drug-induced severe systemic AAV.

Facial nerve palsy associated with atomoxetine-induced hypertension

BACKGROUND Peripheral facial nerve palsy is characterized by unilateral facial paresis due to ipsilateral facial nerve dysfunction. Most cases are idiopathic; however, some have specific etiologies, such as herpesvirus infection, immunological disorders, and hypertension. Atomoxetine is a norepinephrine reuptake inhibitor that is used in the treatment of attention deficit hyperactivity disorder (ADHD). This drug is known to cause adverse effects, such as nausea, appetite loss, headache, insomnia, and hypertension. CASE DESCRIPTION We herein describe a case of sudden-onset right peripheral facial palsy in a 9-year-old Japanese boy. The patients systolic blood pressure was as high as 200 mmHg, and he was therefore admitted to our hospital for investigation. Extensive surveillance including blood examination; endocrinological testing; imaging studies such as computed tomography, magnetic resonance imaging, and renography; and renal biopsy did not reveal any abnormalities. The patient had ADHD and was under treatment with atomoxetine. We discontinued treatment with atomoxetine; the patient showed gradual improvement. His hypertension and facial palsy resolved. We therefore diagnosed the patient with peripheral facial palsy associated with atomoxetine-induced hypertension. CONCLUSION Although peripheral facial nerve palsy is usually benign and self-limiting, blood pressure should be monitored in children under treatment with atomoxetine and the possibility of drug-induced hypertension should be considered in order to prevent palsy associated with hypertension.

Clinical features of children with nontyphoidal Salmonella bacteremia: A single institution survey in rural Japan

Nontyphoidal Salmonella (NTS) can cause bacterial enterocolitis. Although some children with NTS infection develop bacteremia, its clinical manifestations have not been discussed adequately. Therefore, we examined children with NTS bacteremia. We retrospectively examined the medical records of 15 patients aged less than 15 years. Salmonella spp. were detected in the blood cultures of these patients between 1991 and 2014. We divided an additional sample group of 34 patients diagnosed with an NTS infection between 2005 and 2014, into 2 groups. Group bacteremia (B) included patients in whose blood cultures Salmonella spp. were detected, and group non-bacteremia (NB) included patients in whom Salmonella infection was not detected. We compared each group using Wilcoxon test and Fisher’s exact test. The number of patients with fever, diarrhea, or abdominal pain was 15 (100%), 13 (87%), and 9 (60%), respectively, in the first sample of patients. However, vomiting and bloody stool were observed in only 5 patients (33%). More than 70% of patients exhibited a reduced white blood cell count, while C-reactive protein levels were variable in the patients. Salmonella spp. were detected via stool culture in 10 patients (67%). Diarrhea persisted for more than 4 days more frequently in group B than group NB (p = 0.004). The number of patients whose fever persisted for more than 4 days was significantly higher in group B than group NB (p = 0.030). Therefore, if NTS bacteremia is suspected, blood cultures should be collected and antibiotics should be initiated in cases with diarrhea or fever for more than 4 days. Furthermore, a negative stool culture result does not preclude the possibility of NTS bacteremia.

BLOOD PRESSURE IN ADULT PATIENTS WITH CONGENITAL HEART DISEASE

We previously reported that the incidence of hypertension in adult patient with congenital heart disease (CHD) is almost same as that in general population. However, it could be underestimated, because the patients are still young. Moreover, we also reported that the surgical intervention for aortic