The clinical and genetic landscape of early-onset thrombophilia in Japan.

OBJECTIVES: To determine the optimal management for early-onset thrombophilia (EOT), the genetic and clinical features of protein C (PC)-, protein S (PS)-, or antithrombin (AT)-deficient patients of ≤20 years of age were studied in Japan. METHODS/RESULTS: Clinical and genetic information of all genetically diagnosed cases was collected through the prospective, retrospective study, and literature review. One-hundred-one patients had PC (n = 55), PS (n = 29), or AT deficiency (n = 18). One overlapping case had PC- and PS-monoallelic variant. Fifty-five PC-deficient patients (54%) had 26 monoallelic or 29 biallelic variant(s), and 29 (29%) PS-deficient patients had 20 monoallelic or nine biallelic variant(s). None of the patients had AT-biallelic variants. The frequent low-risk allele p.K193del (PC-Tottori) was found in five patients with monoallelic (19%) but not 29 with biallelic variant(s). The most common low-risk allele p.K196E (PS-Tokushima) was found in five with monoallelic (25%) and six with biallelic variant(s) (67%). One exceptional de novo PC variant was found in 32 families with EOT. Only five parents had a history of thromboembolism. Thrombosis concurrently developed in three mother-newborn pairs (two PC deficiency and one AT deficiency). The prospective cohort revealed the outcomes of 35 patients: three deaths with PC deficiency and 20 complication-free survivors. Neurological complications were more frequently found in patients with PC-biallelic variants than those with PC-, PS-, or AT-monoallelic variants (73% vs. 24%, p = .019). CONCLUSIONS: We demonstrate the need for elective screening for EOT targeting PC deficiency in Japan. Early prenatal diagnosis of PC deficiency in mother-infant pairs may prevent perinatal thrombosis in them.

Risk factor analyses for intraventricular hemorrhage in preterm infants: A retrospective cohort study.

BACKGROUND: Very-low-birthweight (VLBW) infants can experience severe intraventricular hemorrhage (IVH) that can lead to life-long disability by impairing neurodevelopment. The aim of this study was to identify the risk and protective factors for severe IVH in VLBW infants. METHODS: A retrospective, cross-sectional review of VLBW infants born at 22-28 weeks' gestation between January 2003 and December 2012 and listed in the Database of Neonatal Research Network in Japan was performed using a statistical model incorporating an odds ratio (OR) and medical center variation as a center variance ratio (CVR). A two-dimensional analysis using a combination of OR and the CVR described evolving measures of a clinical trial (for OR > 1) and standardization (for CVR > 1) concerning a factor of interest. RESULTS: The noteworthy significant protective factors were antenatal steroids (ANS) with and without premature rupture of membrane (OR: 0.43, CVR: 1.08, and OR: 0.68, CVR: 1.14, respectively) and the number of neonatal beds (OR: 0.94, CVR: 0.99) and staff nurses per neonatal bed (OR: 0.89, CVR: 0.99). CONCLUSIONS: Active promotion of ANS administration and consolidation of perinatal medical centers can mitigate the development of severe IVH in VLBW infants.

Protein C system in preterm babies with chronic lung disease: Prospective study.

BACKGROUND: Chronic lung disease (CLD) is a major neonatal pulmonary disorder associated with inflammation. Recent studies have shown that protein C anticoagulant pathways, such as those for protein C (PC), protein S (PS), and thrombomodulin (TM), could be useful indices for reflecting pulmonary injury. However, the involvement of these factors in preterm infants with very low birthweight (VLBW) who have developed CLD remains to be investigated. Here, we investigated whether PC pathway-related factors could predict the development of CLD in preterm infants with VLBW. METHODS: We collected plasma samples from 26 preterm infants with VLBW (13 each from those with and without CLD) at the time of birth and measured TM, PC, and PS levels in their plasmas. We analyzed prospectively the relationship between these factors in infants with and without CLD. RESULTS: There were significant differences in gestational age, birthweight, Apgar score (5 min), and duration of mechanical ventilation between the CLD and non-CLD groups. No significant differences in the PC and PS levels at birth were observed between the two groups, whereas the TM levels in the CLD group were significantly higher than those in the non-CLD group (P = 0.013). The TM levels correlated with gestational age and duration of mechanical ventilation. However, covariance analysis demonstrated that gestational age was significantly associated with TM levels, and consequently, development of CLD was not associated with TM level at birth. CONCLUSIONS: Thrombomodulin, PC, and PS levels at birth could not predict the development of CLD in preterm infants with VLBW.

Clinical Impact of Heritable Thrombophilia on Neonatal-Onset Thromboembolism: A Nationwide Study in Japan.

OBJECTIVE: To clarify the incidence and genetic risk of neonatal-thromboembolism, we conducted a nationwide study exploring the impact of thrombophilia on neonatal-thromboembolism in Japan. STUDY DESIGN: A questionnaire survey was conducted for perinatal centers in Japan, focusing on the clinical expression, genotype, treatment, and outcome of patients who developed thromboembolism within 28 days of birth from 2014 to 2018. RESULTS: The estimated incidence of neonatal-thromboembolism was 0.39 cases per 10 000 live births. Intracranial lesions and purpura fulminans occurred in 66 and 5 of 77 patients, respectively. Fifty-eight (75.3%) infants presented within 3 days after birth. Four (5.2%) died, and 14 (18.2%) survived with disability. At the diagnosis, <20% plasma activity of protein C was noted in 16 infants, protein S (in 2), and antithrombin (in 1). Thirteen genetic tests identified 4 biallelic and 5 monoallelic protein C-variants but no protein S- or antithrombin-variants. Protein C-variants had purpura fulminans (P < .01), ocular bleeding (P < .01), positive-family history (P = .01), and death or disability (P = .03) more frequently than others. Protein C-variants were independently associated with disability (OR 5.74, 95% CI 1.16-28.4, P = .03) but not death. Four biallelic variants had serious thrombotic complications of neurologic disability, blindness, and/or amputation. Three monoallelic variants survived without complications. The only protein C-variant death was an extremely preterm heterozygote infant. CONCLUSIONS: Monoallelic protein C-variants had a higher incidence of neonatal-thromboembolism than biallelic variants. Thrombophilia genetic testing should be performed in the setting of neonatal-thromboembolism and low protein C to identify the underlying genetic defect.

Modelling urea-cycle disorder citrullinemia type 1 with disease-specific iPSCs.

Citrullinemia type 1 (CTLN1) is a urea cycle disorder (UCD) caused by mutations of the ASS1 gene, which is responsible for production of the enzyme argininosuccinate synthetase (ASS), and classically presented as life-threatening hyperammonemia in newborns. Therapeutic options are limited, and neurological sequelae may persist. To understand the pathophysiology and find novel treatments, induced pluripotent stem cells (iPSCs) were generated from a CTLN1 patient and differentiated into hepatocyte-like cells (HLCs). CTLN1-HLCs have lower ureagenesis, recapitulating part of the patient's phenotype. l-arginine, an amino acid clinically used for UCD treatment, improved this phenotype in vitro. Metabolome analysis revealed an increase in tricarboxylic acid (TCA) cycle metabolites in CTLN1, suggesting a connection between CTLN1 and the TCA cycle. This CTLN1-iPSC model improves the understanding of CTLN1 pathophysiology and can be used to pursue new therapeutic approaches.

Incidence of febrile seizure in patients with Down syndrome.

BACKGROUND: It is unclear whether the incidence of febrile seizure (FS) in children with Down syndrome (DS) is higher or lower than in the general population. In this study, we investigated the incidence of FS in DS patients using mailed questionnaires. METHODS: The questionnaires were distributed to parents or caregivers of DS patients attending Osaka Medical College Hospital and six other facilities. The questionnaires were returned by mail from February 2012 to September 2013 from 323 families of DS patients (176 male, 147 female; age range, 3 months-47 years; median age, 5.0 years). To assess the incidence of FS in DS, we performed the following two analyses: (i) we calculated the incidence of FS among DS patients between the ages of 4 and 20 years (n = 199; 113 male, 86 female), and (ii) we extracted families with both DS and healthy siblings between the ages of 4 and 20 years (n = 150; 77 male, 73 female) and compared the incidence of FS in these sibling groups. RESULTS: Five DS patients had a past history of FS. The incidence of FS in DS was 2.5%. The incidence of FS was significantly lower in DS patients compared with healthy siblings (P < 0.003; OR, 0.14). CONCLUSION: The incidence of FS is lower in DS patients than in the general population.

Children with Down's syndrome display high rates of hyperuricaemia.

AIM: Several studies show that hyperuricaemia, abnormally high levels of uric acid in the blood, frequently occurs in adult Down's syndrome patients, but paediatric research is scarce. We aimed to clarify its prevalence in paediatric Down's syndrome patients and its association with lifestyle-related laboratory variables and nutritional intake, to consider possible effects in later life. METHODS: We compared 52 Down's syndrome patients, from one to 15 years of age, with age-matched controls. Hyperuricaemia was defined using reference values established for children, as uric acid z-scores of more than 2.0. Nutritional intake was estimated using 3-day dietary records. RESULTS: Hyperuricaemia occurred in 17 Down's patients (32.7%) and was significantly higher in Down's patients than the controls. The prevalence was also significantly higher in males. There were no significant differences between hyperuricaemia-positive and hyperuricaemia-negative patients in terms of age, body mass index standard deviation scores, fasting blood glucose, insulin, homeostasis model assessment-insulin resistance and triglyceride, and purine body intake was similar. There were differences in high-density lipoprotein cholesterol. CONCLUSION: We found high rates of hyperuricaemia from early childhood in Down's syndrome patients. This suggests careful management of Down's syndrome patients, as hyperuricaemia is an independent risk factor for lifestyle-related diseases in adulthood.

Anticoagulant effects of protein C, protein S, and antithrombin levels on the protein C pathway in young children.

The protein C (PC) pathway involves physiological anticoagulant factors (PC, protein S [PS], and factor V) and performs major anticoagulant functions in adults. Variations in overall PC pathway function due to dynamic changes in PC and PS in early childhood are poorly understood. We aimed to evaluate the contributions of PC pathway function during early childhood by measuring changes in plasma thrombin generation (TG) after administration of the PC activator protac. We evaluated correlations between anticoagulant factors and percentage of protac-induced coagulation inhibition (PiCi%). Before protac addition, TG in newborns (n = 35), infants (n = 42), young children (n = 35), and adults (n = 20) were 525 ± 74, 720 ± 96, 785 ± 53, and 802 ± 64 mOD/min, and PiCi% were 42.1 ± 9.9, 69.8 ± 11.0, 82.9 ± 4.4, and 86.9 ± 3.4%, respectively. The distribution of PiCi% on the two axes of TG (with or without protac) changed continuously with age and differed from that of warfarin-treated plasma and adult PC- or PS-deficient plasma. PiCi% increased dynamically during infancy and correlated with PS levels in newborns and PC levels in young children. Addition of PC or fresh frozen plasma equivalent to approximately 25% PC to PC-deficient plasma improved PiCi%. This automatic measurement requires only a small sample volume and is useful for analysis of developmental hemostasis.

Vitamin K prophylaxis in neonates: comparing two different oral regimens.

OBJECTIVE: This prospective study compared PIVKA-II and PT-INR levels in infants who received two vitamin K (VK) prophylactic regimens. METHODS: A single institution administered 119 healthy newborns 2 mg of VK syrup. Infants were assigned to a 3-time regimen (n = 56) with VK at birth, five days (5D), and 1-month-old (1 M), or a 13-time regimen (n = 63) with VK at birth, 5D, and then weekly for 11 weeks. RESULTS: The 13-time regimen significantly lowered PIVKA-II and reduced PT-INR at 1 M in both breastfed (PIVKA-II: 18-16 mAU/mL, p = 0.02; PT-INR: 1.37-1.13, p < 0.01) and formula-fed infants (PIVKA-II: 18-15 mAU/mL, p = 0.01; PT-INR: 1.54-1.24, p < 0.01), compared to baseline measurements taken at 5D. The 3-time regimen did not significantly alter PIVKA-II levels and only improved PT-INR (2.00-1.50, p < 0.01) in formula-fed infants. CONCLUSION: The 13-time VK regimen significantly enhanced coagulation profiles more effectively than the 3-time regimen.

Late-onset and congenital hearing loss detected using AABR due to congenital cytomegalovirus infection that improved with valganciclovir.

Congenital cytomegalovirus (cCMV) infection is the most common congenital viral infection and is the leading non-genetic cause of sensorineural hearing loss and an important cause of neurodevelopmental disabilities. Auto auditory brainstem response (AABR) is a simple hearing test and used for the purpose of neonatal hearing screening, but can use it for early detection hard of hearing within the study age of the model. We experienced two case of asymptomatic CMV infection in which congenital and late-onset hearing loss were diagnosed early with AABR, and hearing loss improved with valganciclovir.

Urinary lumirubin excretion in jaundiced preterm neonates during phototherapy with blue light-emitting diode vs. green fluorescent lamp.

Phototherapy converts lipophilic unconjugated bilirubin to hydrophilic bilirubin photoisomers, such as lumirubin. We comparatively used a blue light-emitting diode (LED) and a green fluorescent lamp (FL) as light sources for phototherapy of hyperbilirubinemic preterm neonates with the aim of examining potential differences in urinary lumirubin excretion between these two wavelengths. Urinary lumirubin levels were measured using a fluorescence assay with blue light exposure in the presence of the unconjugated bilirubin-inducible fluorescent protein UnaG, and denoted as urinary UnaG-bound bilirubin (UUB)/creatinine (Cr) (µg/mg Cr). Preterm neonates born at ≤ 33 weeks gestational age and treated with phototherapy were subjected to this study. The maximum UUB/Cr level during phototherapy per device intensity was compared between neonates treated with the blue LED and the green FL. A total of 61 neonates were examined to determine the maximum UUB/Cr levels. The median of maximum UUB/Cr excretion per light intensity of each device (µg/mg Cr/µW/cm2/nm) was 0.83 for the blue LED and 1.29 for the green FL (p = 0.01). Green light was found to be more effective than blue one for bilirubin excretion via urinary lumirubin excretion. This is the first spectroscopic study to compare the efficacy of phototherapy at different wavelengths using fluorescence assay.

Clinical and molecular delineation of classical-like Ehlers-Danlos syndrome through a comprehensive next-generation sequencing-based screening system.

Classical-like Ehlers-Danlos syndrome (clEDS) is an autosomal recessive disorder caused by complete absence of tenascin-X resulting from biallelic variation in TNXB. Thus far, 50 patients from 43 families with biallelic TNXB variants have been identified. Accurate detection of TNXB variants is challenging because of the presence of the pseudogene TNXA, which can undergo non-allelic homologous recombination. Therefore, we designed a genetic screening system that is performed using similar operations to other next-generation sequencing (NGS) panel analyses and can be applied to accurately detect TNXB variants and the recombination of TNXA-derived sequences into TNXB. Using this system, we identified biallelic TNXB variants in nine unrelated clEDS patients. TNXA-derived variations were found in >75% of the current cohort, comparable to previous reports. The current cohort generally exhibited similar clinical features to patients in previous reports, but had a higher frequency of gastrointestinal complications (e.g., perforation, diverticulitis, gastrointestinal bleeding, intestinal obstruction, rectal/anal prolapse, and gallstones). This report is the first to apply an NGS-based screening for TNXB variants and represents the third largest cohort of clEDS, highlighting the importance of increasing awareness of the risk of gastrointestinal complications.

Disease-associated mutations in the actin-binding domain of filamin B cause cytoplasmic focal accumulations correlating with disease severity.

Dominant missense mutations in FLNB, encoding the actin-cross linking protein filamin B (FLNB), cause a broad range of skeletal dysplasias with varying severity by an unknown mechanism. Here these FLNB mutations are shown to cluster in exons encoding the actin-binding domain (ABD) and filamin repeats surrounding the flexible hinge 1 region of the FLNB rod domain. Despite being positioned in domains that bind actin, it is unknown if these mutations perturb cytoskeletal structure. Expression of several full-length FLNB constructs containing ABD mutations resulted in the appearance of actin-containing cytoplasmic focal accumulations of the substituted protein to a degree that was correlated with the severity of the associated phenotypes. In contrast, study of mutations leading to substitutions in the FLNB rod domain that result in the same phenotypes as ABD mutations demonstrated that with only one exception disease-associated substitutions, surrounding hinge 1 demonstrated no tendency to form actin-filamin foci. The exception, a substitution in filamin repeat 6, lies within a region previously implicated in filamin-actin binding. These data are consistent with mutations in the ABD conferring enhanced actin-binding activity but suggest that substitutions affecting repeats near the flexible hinge region of FLNB precipitate the same phenotypes through a different mechanism.

Noninvasive monitoring of bilirubin photoisomer excretion during phototherapy.

Lumirubin is the most prevalently excreted hydrophilic bilirubin photoisomer in phototherapy for neonatal jaundice caused by excess hydrophobic unconjugated bilirubin (ZZ-bilirubin). We developed a simple method to estimate the amount of lumirubin by monitoring the reverse photoisomerization of lumirubin to ZZ-bilirubin. Although lumirubin formation was long considered irreversible, exposure to blue light in the presence of the fluorescent protein UnaG, which binds specifically and tightly to ZZ-bilirubin, enables the reverse photoisomerization of lumirubin. This reaction was first detected using a fluorescence assay of neonatal urine sampled during phototherapy and purified lumirubin. The phenomenon of reverse photoisomerization of lumirubin was validated using liquid chromatography-mass spectrometry, which confirmed that lumirubin is reconverted to ZZ-bilirubin in the presence of UnaG. Analyses of 20 urine samples from 17 neonates revealed a significant correlation (correlation coefficient [r] = 0.978; 95% confidence interval 0.867-0.979; P < .001) between lumirubin and ZZ-bilirubin concentration before and after reverse photoisomerization. In general, the rate of photo-reconversion of lumirubin to ZZ-bilirubin is approximately 40%. In conclusion, we demonstrate here that lumirubin can be photo-reconverted to ZZ-bilirubin via exposure to blue light in the presence of UnaG. Utilizing this approach, urinary lumirubin levels can be estimated using an easy-to-perform fluorescence assay.

The balance of comprehensive coagulation and fibrinolytic potential is disrupted in patients with moderate to severe COVID-19.

Coagulation and fibrinolytic mechanisms are enhanced in patients with coronavirus (COVID-19), but disturbances in the balance of both functions in COVID-19 patients remain unclear. We assessed global coagulation and fibrinolysis in plasma from 167 COVID-19 patients (mild/moderate/severe: 62/88/17, respectively) on admission using clot-fibrinolysis waveform analysis (CFWA). Maximum coagulation velocity (|min1|) and maximum fibrinolysis velocity (|FL-min1|) were expressed as ratios relative to normal plasma. Ten patients (6.0%) developed thrombosis, 5 (3.0%) had bleeding tendency, and 13 (7.8%) died during admission. FDP levels increased with severity of COVID-19 symptoms (mild/moderate/severe; median 2.7/4.9/9.9 µg/mL, respectively). The |min1| ratios were elevated in all categories (1.27/1.61/1.58) in keeping with enhanced coagulation potential, with significant differences between mild cases and moderate to severe cases. The |FL-min1| ratios were also elevated in all groups (1.19/1.39/1.40), reflecting enhanced fibrinolytic potential. These data identified coagulation dominance in moderate to severe cases, but balanced coagulation and fibrinolysis in mild cases. There were significant differences in FDP and TAT, but no significant differences in |min1| or |FL-min1| ratios, between patients with and without thrombosis. CFWA monitoring of coagulation and fibrinolysis dynamics could provide valuable data for understanding hemostatic changes and disease status in COVID-19 patients.

Immunohistochemistry and RNA-sequencing have been useful in evaluating the pathological significance of a non-consensus site intronic variant in suspected cases of Lynch syndrome.

Immunohistochemistry of mismatch repair proteins is a universal strategy for Lynch syndrome screening. In this case, Lynch syndrome was suspected, because MLH1 and PMS2 expression was negative by IHC. However, mismatch repair genetic analysis revealed a variant of unknown significance of c.454-13A > G in MLH1. Therefore, we performed reverse transcription-PCR using mRNA extracted from the patient's lymphocytes and detected a heterozygous gene allele indicating splicing abnormalities that complex splicing, with exon 5 followed by only the first codon (ACG) of exon 6 and leading to exon 7 of the MLH1. Two years later, this mutation was corrected to "likely pathogenic". For Lynch syndrome in which mismatch repair protein expression is undetectable by immunohistochemistry, reverse transcription-PCR may be useful to identify an intronic variant of unknown significance as the likely pathogenic variant.

A Pathological Clarification of Sepsis-Associated Disseminated Intravascular Coagulation Based on Comprehensive Coagulation and Fibrinolysis Function.

BACKGROUND: The functional dynamics of coagulation and fibrinolysis in patients with disseminated intravascular coagulation (DIC) vary due to the pathology and severity of various underlying diseases. Conventional measurements of hemostasis such as thrombin-antithrombin complex, plasmin-α2-plasmin-inhibitor complex, and fibrinogen-fibrin degradation products may not always reflect critical pathophysiologic mechanisms in DIC. This article aims to clarify the pathology of sepsis-associated DIC using assessment of comprehensive coagulation and fibrinolysis. METHODS: Plasma samples were obtained from 57 patients with sepsis-associated DIC at the time of initial diagnosis. Hemostasis parameters were quantified by clot-fibrinolysis waveform analysis (CFWA) and thrombin/plasmin generation assays (T/P-GA). The results were expressed as ratios relative to normal plasma. RESULTS: CFWA demonstrated that the maximum coagulation velocity (|min1|) ratio modestly increased to median 1.40 (min - max: 0.10 - 2.60) but the maximum fibrinolytic velocity (|FL-min1|) ratio decreased to 0.61 (0 - 1.19). T/P-GA indicated that the peak thrombin (Th-Peak) ratio moderately decreased to 0.71 (0.22 - 1.20), whereas the peak plasmin (Plm-Peak) ratio substantially decreased to 0.35 (0.02 - 1.43). Statistical comparisons identified a correlation between |min1| and Th-Peak ratios (ρ = 0.55, p < 0.001), together with a strong correlation between |FL-min1| and Plm-Peak ratios (ρ = 0.71, p < 0.001), suggesting that CFWA reflected the balance between thrombin and plasmin generation. With |min1| and |FL-min1| ratios, DIC was classified as follows: coagulation-predominant, coagulation/fibrinolysis-balanced, fibrinolysis-predominant, and consumption-impaired coagulation. The majority of patients in our cohort (80.7%) were coagulation-predominant. CONCLUSION: A pathological clarification of sepsis-associated DIC based on the assessment of coagulation and fibrinolysis dynamics may be useful for the hemostatic monitoring and management of optimal treatment in these individuals.