Current status of surviving patients with arginase 1 deficiency in Japan.

Arginase 1 (ARG1) deficiency is a rare urea cycle disorder (UCD), with an estimated frequency of 1 per 2,200,000 births in Japan. Patients with ARG1 deficiency develop symptoms in late infancy or pre-school age with progressive neurological manifestations and sometimes present with severe hepatic disease. We previously investigated the status of UCDs in Japan; however, only one patient was identified as having ARG1 deficiency. Therefore, we aimed to investigate the current status of patients with ARG1 deficiency in 2018-2021 because almost 10 years have passed since the previous study. We present the disease history, clinical outcome, and treatment of five surviving patients with ARG1 deficiency and discuss the features of ARG1 deficiency in Japan. We found that clinicians often face difficulty in diagnosing ARG1 deficiency at the early stage of onset because of interpatient variability in onset time and clinical manifestations. Blood L-arginine and guanidino compounds were considered to be the major factors causing adverse neurodevelopmental outcomes. Therefore, early detection and intervention of ARG1 deficiency is essential for improved neurodevelopmental outcomes. Liver transplantation has been considered an effective treatment option that can dramatically improve the quality of life of patients, prior to the neurological manifestation of symptoms caused by ARG1 deficiency.

Complications in patients with neurological impairment after gastrostomy.

BACKGROUND: Neurological impairment (NI) is responsible for most conditions that require a permanent gastrostomy tube. The present study assessed the occurrence of short- and long-term complications after video-assisted gastrostomy (VAG) in patients with NI. METHODS: The incidence of short- (<6 months) and long-term (over 2 years) complications of VAG were analyzed in a retrospective study. The differences between the incidence of the complications of VAG according to the age at surgery (≤15 years vs. ≥16 years) were also evaluated. The short- and long-term complications observed were granulation tissue formation, infection requiring antibiotic treatment, skin problems, perigastrostomy leakage, vomiting, accidental tube dislodgement, dumping syndrome, ileus, and peritonitis. RESULTS: Eighty-two patients were evaluated for short- and long-term complications. The long-term complication rate was significantly lower than the short-term complication rate (P = 0.0026). Onodera's prognostic nutritional index before VAG in patients with long-term complications was significantly lower than in patients without such complications (P = 0.046). The incidence of long-term granulation tissue formation, infection, and vomiting were significantly lower than those of similar short-term complications. Long-term skin problems were associated with short-term skin problems (odds ratio: 18.95; 95% confidence interval: 4.53-92.98; P < 0.001). The number of patients ≥16 years old with short- and long-term skin problems was significantly higher than in patients ≤15 years old (P = 0.0014 and P = 0.0073, respectively). CONCLUSIONS: The incidence rate of granulation tissue formation and infection after VAG were lower in the long term than in the short term. However, patients ≥16 years old presented with persistent complications.

Sodium phenylbutyrate improved the clinical state in an adult patient with arginase 1 deficiency.

An adult female patient was diagnosed with arginase 1 deficiency (ARG1-D) at 4 years of age, and had been managed with protein restriction combined with sodium benzoate therapy. Though the treatment was successful in ameliorating hyperammonemia, hyperargininemia persisted. After being under control with a strict restriction of dietary protein, severe fall of serum albumin levels appeared and her condition became strikingly worsened. However, after sodium phenylbutyrate (NaPB) therapy was initiated, the clinical condition and metabolic stability was greatly improved. Current management of ARG1-D is aimed at lowering plasma arginine levels. The nitrogen scavengers, such as NaPB can excrete the waste nitrogen not through the urea cycle but via the alternative pathway. The removal of nitrogen via alternative pathway lowers the flux of arginine in the urea cycle. Thereby, the clinical complications due to insufficient amount of protein intake can be prevented. Thus, NaPB therapy can be expected as a useful therapeutic option, particularly in patients with ARG1-D.

Factor XII Shizuoka, a novel mutation (Ala392Thr) identified and characterized in a patient with congenital coagulation factor XII deficiency.

We identified a novel mutation (Ala392Thr) in the factor XII (FXII) gene of a patient with congenital FXII deficiency, designated Factor XII Shizuoka. The proband was an asymptomatic 63-year-old Japanese male with an abnormal coagulation test, discovered by chance during preoperative testing. The FXII activity was under 3% and antigen level was under 10%. Sequence analysis of the proband's FXII gene revealed a homozygous nucleotide substitution G to A in exon 10, resulting in the amino acid substitution Ala392 to Thr in the catalytic domain. We constructed the mutant FXII cDNA in an expression plasmid vector and transfected it into Chinese hamster ovary (CHO) cells. The recombinant wild-type FXII antigen was detected in the culture medium by immunoprecipitation assay, but the mutant FXII (A392T) was not observed. Both the wild-type FXII and A392T cell lysates, however, contained equivalent levels of FXII antigen and FXII mRNA, as estimated by Western blotting and quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. These findings suggest that the Ala392 to Thr substitution impairs intracellular protein processing and causes a cross-reacting material -negative FXII deficiency.

Elevated urine pregnanetriolone definitively establishes the diagnosis of classical 21-hydroxylase deficiency in term and preterm neonates.

Elevated blood 17alpha-hydroxyprogesterone (17OHP) level, although widely used for the screening of classical 21-hydroxylase deficiency (21OHD) in neonates, has frequently been found in some neonates without classical 21OHD, particularly preterm neonates. We studied the diagnostic value of the metabolite of 21-deoxycortisol (pregnanetriolone, Ptl) and the metabolite of 17OHP (pregnanetriol, PT) in identifying 21OHD in term and preterm neonates with elevated blood 17OHP on the newborn screening. Spot urine samples from 59 classical 21OHD neonates (50 term, 9 preterm), 83 neonates without 21OHD having transiently elevated blood 17OHP (non-21OHD) (49 term, 34 preterm), and 62 control term neonates were studied using gas chromatography/mass spectrometry in selected ion monitoring analysis for Ptl, PT, 5beta-tetrahydrocortisone (betaTHE), and 5alpha-tetrahydrocortisone (alphaTHE). Ptl and Ptl/(betaTHE+alphaTHE) showed no overlap between 21OHD and non-21OHD, and 21OHD and controls, respectively (Ptl was 0.46-124 mg/g creatinine in 21OHD term, 0.80-26.9 mg/g creatinine in 21OHD preterm, < or = 0.08 mg/g creatinine in non-21OHD term, < or =0.06 mg/g creatinine in non-21OHD preterm, and < or = 0.07 mg/g creatinine in controls). PT and PT/(betaTHE+alphaTHE) showed significant overlap between 21OHD and non-21OHD. The above data indicate that spot urine Ptl is a highly specific marker of 21OHD with a cutoff value of 0.1 mg/g creatinine, yielding an unambiguous separation between 21OHD and non-21OHD in term and preterm neonates.

Genetic analyses and expression studies identified a novel mutation (W486C) as a molecular basis of congenital coagulation factor XII deficiency.

We analyzed the factor XII (FXII) gene of a patient with congenital FXII deficiency and identified a novel amino acid substitution (W486C) in the catalytic domain. The proband was an asymptomatic 49-year-old Japanese female with abnormal coagulation test, discovered by chance. The FXII activity and antigen level were both under 10%, suggesting a cross-reacting material-negative FXII deficiency. Sequence analysis of the proband's FXII gene revealed a homozygous nucleotide substitution G --> C in exon 12, resulting in the amino acid substitution W486C in the catalytic domain. We constructed the mutant FXII cDNA in an expression plasmid vector and transfected it into Chinese hamster ovary cells. The recombinant wild-type FXII antigen was detected in the culture medium by immunoprecipitation assay, but the mutant FXII (W486C) was not observed. On the other hand, both the wild-type FXII and W486C cell lysates contained FXII antigen and FXII mRNA, as estimated by western blotting and quantitative reverse transcriptase-polymerase chain reaction. These findings suggest that the W486C substitution of FXII impairs intracellular processing of the protein and/or transport system.

Endothelin-1 regulates cardiac sympathetic innervation in the rodent heart by controlling nerve growth factor expression.

The cardiac sympathetic nerve plays an important role in regulating cardiac function, and nerve growth factor (NGF) contributes to its development and maintenance. However, little is known about the molecular mechanisms that regulate NGF expression and sympathetic innervation of the heart. In an effort to identify regulators of NGF in cardiomyocytes, we found that endothelin-1 specifically upregulated NGF expression in primary cultured cardiomyocytes. Endothelin-1-induced NGF augmentation was mediated by the endothelin-A receptor, Gibetagamma, PKC, the Src family, EGFR, extracellular signal-regulated kinase, p38MAPK, activator protein-1, and the CCAAT/enhancer-binding protein delta element. Either conditioned medium or coculture with endothelin-1-stimulated cardiomyocytes caused NGF-mediated PC12 cell differentiation. NGF expression, cardiac sympathetic innervation, and norepinephrine concentration were specifically reduced in endothelin-1-deficient mouse hearts, but not in angiotensinogen-deficient mice. In endothelin-1-deficient mice the sympathetic stellate ganglia exhibited excess apoptosis and displayed loss of neurons at the late embryonic stage. Furthermore, cardiac-specific overexpression of NGF in endothelin-1-deficient mice overcame the reduced sympathetic innervation and loss of stellate ganglia neurons. These findings indicate that endothelin-1 regulates NGF expression in cardiomyocytes and plays a critical role in sympathetic innervation of the heart.

[Genetic risk factors for ischemic cerebrovascular disease--analysis on fifteen candidate prothrombotic gene polymorphisms in the Japanese population].

Accumulating evidence suggests that several polymorphisms in factors regulating blood coagulation, platelet function, and lipid metabolism are relevant for susceptibility to ischemic cerebrovascular diseases (CVD). The present study analyzed 15 genetic polymorphisms possibly associated with atherosclerosis and thrombosis in a case-control study involving a total of 200 genetically unrelated Japanese patients with ischemic CVD (mean age 58.3 +/- 7.6 y) and 281 age- and gender-matched control subjects (59.0 +/- 4.1 y). Control subjects were randomly selected from unrelated donors with no history of documented CVD or any type of cardiovascular disease with normal resting electrocardiograms. Among the factors genotyped, two factors, platelet glycoprotein (GP) Ib alpha (Thr145Met) and NADPH oxidase p22phox (His72Tyr), were significantly associated with CVD after adjustment for acquired risk factors including hypertension, diabetes mellitus, hyperlipidemia, and smoking. For those with age < 60 y, 10.6% of the CVD patients and 2.9% of the control subjects had both of the two risk genotypes (GPIb alpha 145Met and p22phox 72Tyr, p < 0.05). The mean onset-age of CVD was 58.6 +/- 7.7 y for those having no or only one risk genotype, while 53.3 +/- 5.5 y for those having both of the risk genotypes (p < 0.05). Thus, GPIb alpha 145Met and p22phox 72 Tyr are the genetic factors associated with the risk of ischemic CVD in the Japanese. Carrying both of the two mutations might be associated with developing CVD at a younger age.

Reference values for urinary steroids in Japanese newborn infants: gas chromatography/mass spectrometry in selected ion monitoring.

Urinary steroid profile analysis using gas chromatography/mass spectrometry (GC/MS) has been reported for the diagnosis of abnormal steroidogenesis in newborn infants with some success. We tried to establish the reference values of 63 urinary steroids in Japanese newborn infant, using GC/MS in selected ion monitoring (SIM) that utilizes two characteristic mass ions for each steroid for definitive identification. We studied 36 healthy full-term newborn infants (1-56 days of age) on spot urine samples to define the reference values (mg/g creatinine, median and 10-90 percentile range) and to investigate the possible difference between daytime and nighttime levels. We also studied 23 healthy adult females (20-24 years of age) on 24-hour-urine for the comparison of the reference values of newborn infants. Fifty metabolites of DHEA, pregnenolone, 17-hydroxypregnenolone, androstenedione, progesterone, 17-hydroxyprogesterone, 21-deoxycortisone, corticosterone, 18-hydroxycorticosterone, aldosterone, 18-hydroxycortisol, 11-deoxycortisol, cortisone, cortisol, and estrogen in each infant were measurable without interference, but 13 metabolites of 11-hydroxyandrostenedione, pregnenolone, 11-deoxycorticosterone, corticosterone, 11-dehydrocorticosterone, 21-deoxycortisol, 11-deoxycortisol and cortisol were unmeasurable in each infant due to the interference of fetal cortex steroids as confirmed by abnormal peak area ratios of two mass ions. All 63 metabolites in each control adult were measurable without interference. 16alpha-, 16beta-, and 15beta-hydroxy metabolites of 3beta-hydroxy-5-en-steroids, and 6beta-, 18-hydroxy and 11-oxo-metabolites of corticosteroids were significantly higher in full-term newborn infants than those in adults as previously reported. Urinary steroids showed little circadian variation in the newborn infants, indicating that spot urine can substitute for 24-hour urine.

[Study of genotype frequencies of ANP 664G/A polymorphism in normal subjects and CVD patients, and its association with plasma ANP levels].

Atrial natriuretic peptide (ANP) plays a crucial role in regulating body fluid volume and blood pressure, by promoting natriuresis and vasodilatation and by inhibiting the renin-angiotensin system. Plasma levels of ANP are elevated in heart failure and hypertension, and ANP is thus believed to be involved in the pathogenesis of cardiovascular disorders. Previous case-control studies have shown that a single nucleotide polymorphism in the first exon of ANP gene, 664G/A, is associated with a risk of cerebrovascular disease (CVD) in white populations. Plasma ANP levels, however, were not evaluated in these studies in relation to the 664G/A, although the nucleotide substitution causes an amino-acid change in the propeptide of ANP. In this study, we analyzed the genotype frequencies of the 664G/A in Japanese patients with CVD (n = 199) and age- and gender-matched control subjects(n = 176). Genotypes with the 664A allele in the Japanese control subjects (G/A and A/A 12.5%) were apparently more frequent compared to the published frequency of the white control population (G/A and A/A 6.6%, p = 0.0437). Genotypes with the 664A allele, however, were not significantly different between our CVD patients(15.1%) and controls (12.5% p = 0.4714). In the control group (n = 137), the mean plasma ANP levels were not different between the 664G/G (15.7 +/- 10.7 pg/ml) and 664G/A genotypes (15.6 +/- 6.8 pg/ml, p = 0.9708). These results suggest that there is a racial difference in the allele frequency of 664G/A, and that this polymorphism may not be a major risk factor for CVD in the Japanese, nor is it a major determinant of plasma ANP level.