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Periodontitis is an inflammatory disease causing loss of tooth-supporting periodontal tissue. Disease susceptibility to the rapidly progressive form of periodontitis, aggressive periodontitis (AgP), appears to be influenced by genetic risk factors. To identify these in a Japanese population, we performed whole exome sequencing of 41 unrelated generalized or localized AgP patients. We found that AgP is putatively associated with single nucleotide polymorphism (SNP) rs536714306 in the G-protein coupled receptor 126 gene, GPR126 [c.3086 G>A (p.Arg1029Gln)]. Since GPR126 activates the cAMP/PKA signaling pathway, we performed cAMP ELISA analysis of cAMP concentrations, and found that rs536714306 impaired the signal transactivation of GPR126. Moreover, transfection of human periodontal ligament (HPDL) cells with wild-type or mutant GPR126 containing rs536714306 showed that wild-type GPR126 significantly increased the mRNA expression of bone sialoprotein, osteopontin, and Runx2 genes, while mutant GPR126 had no effect on the expression of these calcification-related genes. The increase in expression of these genes was through the GPR126-induced increase of bone morphogenic protein-2, inhibitor of DNA binding (ID) 2, and ID4 expression. These data indicate that GPR126 might be important in maintaining the homeostasis of periodontal ligament tissues through regulating the cytodifferentiation of HPDL cells. The GPR126 SNP rs536714306 negatively influences this homeostasis, leading to the development of AgP, suggesting that it is a candidate genetic risk factor for AgP in the Japanese population.

Congenital portosystemic shunts (CPSSs) are often associated with life-threatening systemic complications, which may be detected by identifying hypergalactosemia in newborn screening (NBS). However, diagnosing CPSS at an early stage is not easy. The purpose of this study was to predict CPSS early using screening values and general blood tests. The medical records of 153 patients with hypergalactosemia who underwent NBS in Saitama Prefecture between 1 December 1997 and 31 October 2023 were retrospectively analyzed. We provided the final diagnosis of the analyzed patients. Of the 153 patients, 44 (29%) were in the CPSS group and 83 (54%) were in the transient galactosemia group. Using the initial screening items and the six blood test items, we attempted to extract a CPSS group from the transient galactosemia group. Finally, a model for CPSS prediction was established. From multiple logistic regression analysis, filtered blood galactose-1 phosphate/galactose, serum total bile acid, and ammonia were adopted as explanatory variables for the prediction model. If the cut-off value for predicted disease probability value (P) was >0.357, CPSS was identified with 86.4% sensitivity (95%CI 72.6–94.8%) and 81.9% specificity (95%CI 72.0–89.5%). This predictive model might allow prediction of CPSS and early intervention.

Background Sengers syndrome is an autosomal recessive mitochondrial DNA depletion syndrome characterized by hypertrophic cardiomyopathy, congenital cataracts, skeletal myopathy, exercise intolerance, and lactic acidosis. Dysfunction of acylglycerol kinase (AGK) is responsible for the disease, and several AGK gene variants have been reported. Methods We employed a comprehensive genomic analysis approach, including whole‐genome sequencing and RNA sequencing, combined with various bioinformatics tools. Results Our analysis successfully diagnosed Sengers syndrome in a patient by detecting a known pathogenic variant and a previously unreported large deletion involving the AGK gene in a segmental duplication. Conclusion This study demonstrates the effectiveness of combining multiple genomic analysis approaches for the accurate diagnosis of Sengers syndrome, particularly in cases involving complex genetic variations such as large deletions in segmental duplications. Sengers syndrome, characterized by hypertrophic cardiomyopathy, congenital cataracts, skeletal myopathy, exercise intolerance, and lactic acidosis, is caused by mutations in the AGK gene. This study reports the successful diagnosis of Sengers syndrome using comprehensive genomic analysis, identifying both a known pathogenic AGK variant and a previously unreported large deletion in a segmental duplication region.

AbstractMaternal health and nutritional status influence offspring health and the diseases that may develop in them. The effects of maternal inflammation on offspring from the perspective of the inflammatory response and immune changes are not fully understood. We hypothesized that maternal inflammation modulates immune and metabolic functions, affecting the pathophysiology of inflammatory diseases in offspring. This study investigated whether maternal inflammation affects the onset of collagen-induced arthritis (CIA), a murine model of human rheumatoid arthritis. Female DBA/1J mice received a single intraperitoneal injection of lipopolysaccharide (LPS) 5 days before conception. Male offspring of LPS-treated dams were placed in the maternal LPS group (MLG). To induce CIA, type II collagen (CII) was emulsified with Freund’s complete adjuvant and injected twice into each mouse, at 13 and 16 weeks. The offspring were sacrificed at 26 weeks to analyze immunological and metabolic parameters. The degree of joint swelling at an early stage of CIA was lower in the MLG than in the control group. From histological analysis, the severity of joint destruction (severity of arthritis score) and CII-specific IgG titer were significantly lower in the MLG. However, at 26 weeks, serum interleukin (IL)-6 levels, an index of CIA disease activity, were significantly higher in the MLG. Moreover, serum leptin levels were lower in the MLG, and a negative correlation between leptin and serum IL-6 was observed. In conclusion, maternal inflammation does not merely suppress inflammation; it may delay CIA in offspring. The analysis of inflammatory cytokines and leptin concentrations at 26 weeks suggests that the pathophysiology of arthritis was worsening. This study also suggests that maternal inflammation modulates postnatal inflammatory response patterns in offspring.

In the search for sequence variants underlying disease, commonly applied filtering steps usually result in a number of candidate variants that cannot further be narrowed down. In autosomal recessive families, disease usually occurs only in one generation so that genetic linkage analysis is unlikely to help. Because homozygous recessive mutations tend to be inherited together with flanking homozygous variants, we developed a statistical method to detect pathogenic variants in autosomal recessive families: We look for differences in patterns of homozygosity around candidate variants between patients and control individuals and expect that such differences are greater for pathogenic variants than random candidate variants. In six autosomal recessive mitochondrial disease families, in which pathogenic homozygous variants have already been identified, our approach succeeded in prioritizing pathogenic mutations. Our method is applicable to single patients from recessive families with at least a few dozen control individuals from the same population; it is easy to use and is highly effective for detecting causative mutations in autosomal recessive families.

ObjectiveNeonatal-onset mitochondrial disease has not been fully characterised owing to its heterogeneity. We analysed neonatal-onset mitochondrial disease in Japan to clarify its clinical features, molecular diagnosis and prognosis.DesignRetrospective observational study from January 2004 to March 2020.SettingPopulation based.PatientsPatients (281) with neonatal-onset mitochondrial disease diagnosed by biochemical and genetic approaches.InterventionsNone.Main outcome measuresDisease types, initial symptoms, biochemical findings, molecular diagnosis and prognosis.ResultsOf the 281 patients, multisystem mitochondrial disease was found in 194, Leigh syndrome in 26, cardiomyopathy in 38 and hepatopathy in 23 patients. Of the 321 initial symptoms, 236 occurred within 2 days of birth. Using biochemical approaches, 182 patients were diagnosed by mitochondrial respiratory chain enzyme activity rate and 89 by oxygen consumption rate. The remaining 10 patients were diagnosed using a genetic approach. Genetic analysis revealed 69 patients had nuclear DNA variants in 36 genes, 11 of 15 patients had mitochondrial DNA variants in five genes and four patients had single large deletion. The Cox proportional hazards regression analysis showed the effects of Leigh syndrome (HR=0.15, 95% CI 0.04 to 0.63, p=0.010) and molecular diagnosis (HR=1.87, 95% CI 1.18 to 2.96, p=0.008) on survival.ConclusionsNeonatal-onset mitochondrial disease has a heterogenous aetiology. The number of diagnoses can be increased, and clarity regarding prognosis can be achieved by comprehensive biochemical and molecular analyses using appropriate tissue samples.

Background Mitochondrial DNA depletion syndrome (MTDPS) is part of a group of mitochondrial diseases characterized by a reduction in mitochondrial DNA copy number. Most MTDPS is caused by mutations in genes that disrupt deoxyribonucleotide metabolism. Methods We performed the whole‐exome sequencing of a hepato‐encephalopathy patient with MTDPS and functional analyses to determine the clinical significance of the identified variant. Results Here, whole‐exome sequencing of a patient presenting with hepato‐encephalopathy and MTDPS identified a novel homozygous frameshift variant, c.13_29del (p.Trp6Profs*71) in MICOS13. MICOS13 (also known as QIL1, MIC13, or C19orf70) is a component of the MICOS complex, which plays crucial roles in the maintenance of cristae junctions at the mitochondrial inner membrane. We found loss of MICOS13 protein and fewer cristae structures in the mitochondria of fibroblasts derived from the patient. Stable expression of a wild‐type MICOS13 cDNA in the patients fibroblasts using a lentivirus system rescued mitochondrial respiratory chain complex deficiencies. Conclusion Our findings suggest that the novel c.13_29del (p.Trp6Profs*71) MICOS13 variant causes hepato‐encephalopathy with MTDPS. We propose that MICOS13 is classified as the cause of MTDPS. We performed the whole‐exome sequencing of the hepato‐encephalopathy patient with MTDPS. The functional analyses revealed the clinical significance of the identified variant.

Abstract Aims Cardiac myosin light chain kinase (cMLCK) phosphorylates ventricular myosin regulatory light chain 2 (MLC2v) and regulates sarcomere and cardiomyocyte organization. However, few data exist regarding the relationship between cMLCK mutations and MLC2v phosphorylation, particularly in terms of developing familial dilated cardiomyopathy (DCM) in whom cMLCK gene mutations were identified. The purpose of the present study was to investigate functional consequences of cMLCK mutations in DCM patients. Methods and results The diagnosis of DCM was based on the patients' history and on echocardiography. We screened cMLCK gene mutations in DCM probands with high resolution melting analysis. Known DCM-causing genes mutations were excluded by exome sequencing of family members. MLC2v phosphorylation was analysed by Phos-tag sodium dodecyl sulfate–polyacrylamide gel electrophoresis assays. We also performed ADP-Glo assays for determining the total amount of adenosine triphosphate used in the kinase reaction. Unrelated DCM probands (109 males and 40 females) were enrolled in this study, of which 16 were familial and 133 sporadic. By mutation screening, a truncation variant of c1915-1 g>t (p.Pro639Valfs*15) was identified, which was not detected in 400 chromosomes of 200 healthy volunteers; it is listed in the Human Genetic Variation Database with an allele frequency < 0.001. In the proband, the presence of mutations in known DCM-causing genes was excluded with exome analysis. Familial analysis identified a 19-year-old male carrier who manifested slight left ventricular dilation with preserved systolic function. Phosphorylation assays analysed by Phos-tag SDS-PAGE revealed that the identified p.Pro639Valfs*15 mutation results in a complete lack of kinase activity, although it did not affect wild-type cMLCK activity. ADP-Glo assays confirmed that the mutant cMLCK had no kinase activity, whereas wild-type cMLCK had a Km value of 5.93 ± 1.47 μM and a Vmax of 1.28 ± 0.03 mol/min/mol kinase. Conclusions These results demonstrate that a truncation mutation in the cMLCK gene p.Pro639Valfs*15 can be associated with significant impairment of MLC2v phosphorylation and possibly with development of DCM, although a larger study of DCM patients is required to determine the prevalence of this mutation and further strengthen its association with disease development.

A major challenge in current exome sequencing in autosomal recessive (AR) families is the lack of an effective method to prioritize single-nucleotide variants (SNVs). AR families are generally too small for linkage analysis and length of homozygous regions is unreliable for identification of causative variants. Various common filtering steps usually result in a list of candidate variants that cannot be narrowed down further or ranked. To prioritize shortlisted SNVs we consider each homozygous candidate variant together with a set of SNVs flanking it. We compare the resulting array of genotypes between an affected family member and a number of control individuals and argue that, in a family, differences between family member and controls should be larger for a pathogenic variant and SNVs flanking it than for a random variant. We assess differences between arrays in two individuals by the Hamming distance and develop a suitable test statistic, which is expected to be large for a causative variant and flanking SNVs. We prioritize candidate variants based on this statistic and applied our approach to six patients with known pathogenic variants and found these to be in the top 2 to 10 percentiles of ranks.

Variability in intracoronary computed tomography (CT) number may influence vessel quantification. We confirmed the feasibility of a novel method for measuring vessel diameter and area using coronary CT angiography (CCTA) with an optimized intracoronary CT number, 350 HU. We performed intravascular ultrasound (IVUS) imaging in 52 patients with significant stenosis detected by coronary CT angiography targeting 350 HU using a CT number-controlling system. We measured 0-to-0 HU distances in the cross-sectional coronary images of 32 patients. We analyzed the ratio of 0-to-0 HU distances in CT images to media-to-media distances in IVUS images (C:I ratio). The area of ≥0 HU for 103 representative points in the remaining 20 patients was compared to the area of the traced external elastic membrane (EEM) in IVUS images. There was a strong correlation between 0-to-0 HU distance in CT images and media-to-media diameter in IVUS images (r = 0.97, p<0.001). The C:I ratio was 1.1. EEM area was estimated by dividing the area of ≥0 HU by the square of C:I. There was also a strong correlation between the estimated EEM area and the EEM area in IVUS images (r = 0.95, p<0.001). Media-to-media diameter and EEM area can be estimated by CCTA targeting the optimized intracoronary CT number when blood vessel borders are defined at 0 HU.