Guide for diagnosis and treatment of hyperphenylalaninemia.

IMPORTANCE: Sapropterin hydrochloride, a natural coenzyme (6R-tetrahydrobiopterin) of phenylalanine hydroxylase, was first approved as a treatment for tetrahydrobiopterin deficiency in 1992 in Japan, and was then approved as a treatment for a tetrahydrobiopterin-responsive hyperphenylalaninemia in 2007 and 2008, in the USA and Japan, respectively. Guidelines are required on the proper use of sapropterin hydrochloride for tetrahydrobiopterin-responsive hyperphenylalaninemia. OBSERVATIONS: It is recommended that tetrahydrobiopterin-responsive hyperphenylalaninemia should be diagnosed in all cases of hyperphenylalaninemia, including phenylketonuria, by tetrahydrobiopterin administration tests rather than by phenotype or blood phenylalanine levels. CONCLUSIONS AND RELEVANCE: If tetrahydrobiopterin-responsive hyperphenylalaninemia is diagnosed, all ages can be treated with sapropterin hydrochloride. Although there are reports that sapropterin hydrochloride is effective and safe for the prevention of maternal phenylketonuria, further investigation is required.

Effect of L-Carnitine on Amino Acid Metabolism in Elderly Patients Undergoing Regular Hemodialysis.

INTRODUCTION: Among patients regularly undergoing hemodialysis, hypocarnitinaemia often develops as a consequence of inadequate dietary intake, reduced synthesis in the body, and considerable losses during hemodialysis. OBJECTIVES: To evaluate the effects of L-carnitine supplementation on patients with end-stage kidney disease (ESKD) who underwent hemodialysis. METHODS: Thirty-one patients with ESKD, comprising 18 men and 13 women, with a median age of 72 (range 58-89) years, who underwent regular hemodialysis received treatment with L-carnitine for 1 year. The total and free carnitine, acylcarnitine, and amino acids (AA) levels before and after L-carnitine treatment were analyzed, and the blood biochemistry results and clinical profiles of the subjects were compared before and after treatment. RESULTS: The median (interquartile range [IQR]) serum total and free carnitine and acylcarnitine levels significantly increased from 34.5 (28.2-44.3), 20.9 (15.8-27.6), and 14.1 (11.2-17.6) µmol/L, respectively to 407.4 (371.6-493.5), 270.2 (228.3-316.0), and 155.0 (136.1-168.5) µmol/L, respectively, after treatment (all p < 0.001). The median (IQR) blood valine, tyrosine, phenylalanine, and citrulline levels increased from 0.94 (0.80-1.09), 0.45 (0.39-0.55), 0.61 (0.56-0.79), and 1.04 (0.79-1.26) mg/dL, respectively to 1.24 (1.13-1.54), 0.76 (0.62-0.85), 0.90 (0.70-1.04), and 1.22 (0.92-1.39) mg/dL, respectively, following L-carnitine treatment (p < 0.001, p < 0.001, p = 0.002, and p = 0.030, respectively); however, the median (IQR) blood arginine level decreased from 0.20 (0.13-0.24) to 0.09 (0.06-0.14) mg/dL after treatment (p < 0.001). The median (IQR) percentage fractional shortening (41.5 vs. 41.9%; p = 0.012) and left ventricular ejection fraction (65.2 vs. 67.3%; p = 0.036) increased significantly following treatment. CONCLUSIONS: L-Carnitine increased the blood acylcarnitine levels, enhanced fatty acid metabolism, and affected AAs metabolism; this may be beneficial for energy production within the cardiac and skeletal muscles.

LSD1 mediates metabolic reprogramming by glucocorticoids during myogenic differentiation.

The metabolic properties of cells are formed under the influence of environmental factors such as nutrients and hormones. Although such a metabolic program is likely initiated through epigenetic mechanisms, the direct links between metabolic cues and activities of chromatin modifiers remain largely unknown. In this study, we show that lysine-specific demethylase-1 (LSD1) controls the metabolic program in myogenic differentiation, under the action of catabolic hormone, glucocorticoids. By using transcriptomic and epigenomic approaches, we revealed that LSD1 bound to oxidative metabolism and slow-twitch myosin genes, and repressed their expression. Consistent with this, loss of LSD1 activity during differentiation enhanced the oxidative capacity of myotubes. By testing the effects of various hormones, we found that LSD1 levels were decreased by treatment with the glucocorticoid dexamethasone (Dex) in cultured myoblasts and in skeletal muscle from mice. Mechanistically, glucocorticoid signaling induced expression of a ubiquitin E3 ligase, JADE-2, which was responsible for proteasomal degradation of LSD1. Consequently, in differentiating myoblasts, chemical inhibition of LSD1, in combination with Dex treatment, synergistically de-repressed oxidative metabolism genes, concomitant with increased histone H3 lysine 4 methylation at these loci. These findings demonstrated that LSD1 serves as an epigenetic regulator linking glucocorticoid action to metabolic programming during myogenic differentiation.

Urea cycle disorders-update.

The urea cycle is a metabolic pathway for the disposal of excess nitrogen, which arises primarily as ammonia. Nitrogen is essential for growth and life-maintenance, but excessive ammonia leads to life-threatening conditions. The urea cycle disorders (UCDs) comprise diseases presenting with hyperammonemia that arise in either the neonatal period (about 50% of cases) or later. Congenital defects of the enzymes or transporters of the urea cycle cause the disease. This cycle utilizes five enzymes, two of which, carbamoylphosphate synthetase 1 and ornithine transcarbamylase are present in the mitochondrial matrix, whereas the others (argininosuccinate synthetase, argininosuccinate lyase and arginase 1) are present in the cytoplasm. In addition, N-acetylglutamate synthase and at least two transporter proteins are essential to urea cycle function. Severity and age of onset depend on residual enzyme or transporter function and are related to the respective gene mutations. The strategy for therapy is to prevent the irreversible toxicity of high-ammonia exposure to the brain. The pathogenesis and natural course are poorly understood because of the rarity of the disease, so an international registry system and novel clinical trials are much needed. We review here the current concepts of the pathogenesis, diagnostics, including genetics and treatment of UCDs.

High-risk screening for Anderson-Fabry disease in patients with cardiac, renal, or neurological manifestations.

Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder caused by abnormalities in the α-galactosidase (Gal) A gene (GLA; MIM:300644). The reduced activity of the lysosomal enzyme, α-galactosidase A (α-Gal A) leads to classic early manifestations and vascular disease of the heart, kidneys, and brain. As a high-risk screening for symptomatic AFD using an enzymatic assay on dried blood spot samples, we enrolled 2325 individuals (803 females and 1522 males; median age: 66 years) with cardiac, renal, or neurological manifestations that met at least one of the following criteria: (a) family history of early-onset cardiovascular diseases; (b) typical classic manifestations, such as acroparesthesias, clustered angiokeratoma, cornea verticillata, and hypo-anhidrosis; (c) proteinuria; (d) receiving dialysis; (e) left ventricular hypertrophy on electrocardiography or echocardiography; or (f) history of stroke. Ninety-two patients displayed low α-Gal A activity. Four males and two females had different pathogenic GLA mutations (0.26%) including a novel mutation c.908-928del21. Four males (0.17%) harbored the GLA c.196G>C (p.E66Q) variant. This simple screening protocol using dried blood spot samples is useful for early diagnosis of AFD in high-risk and underdiagnosed patients suffering from various cardiac, renal, or neurological manifestations.

Newborn screening for Pompe disease in Japan: report and literature review of mutations in the GAA gene in Japanese and Asian patients.

A newborn screening program for Pompe disease using dried blood spots (DBSs) was initiated in Japan. Here, we summarized this screening program and described the results of the GAA gene analysis. From April 2013 to November 2016, 103,204 newborns were screened; 71 had low acid alpha-glucosidase (AαGlu) activity. GAA sequencing showed that 32 (45.1%) and 37 (52.1%) of these newborns were homozygous and heterozygous for pseudodeficiency alleles c.[1726G>A; 2965G>A], respectively. Moreover, 24 of 32 newborns with homozygous c.[1726G>A; 2965G>A] alleles had no mutations, and the other eight had one mutation each. Thirty-five of 37 newborns with heterozygous c.[1726G>A; 2965G>A] alleles had one mutation, and the other two had two mutations each. Only one newborn who had two mutations did not harbor c.[1726G>A; 2965G>A] alleles. Thus, it was difficult to distinguish newborns with c.[1726G>A; 2965G>A] alleles from newborns with pre-symptomatic Pompe disease using AαGlu assays in DBSs or fibroblasts; GAA gene sequencing was necessary. Seventy-one newborns had 50 variants, including 21 mutations or predictably pathogenic variants, and 29 polymorphisms or predictably non-pathogenic variants. Four of 21 mutations or predictably pathogenic variants and four of 29 polymorphisms or predictably non-pathogenic variants were novel. No infantile-onset Pompe disease was detected, and three newborns were diagnosed with potential late-onset Pompe disease. In the literature, 156 variants have been reported for 296 patients from 277 families in 41 articles from Japan, Korea, Taiwan, and China. Our results provide insights into GAA gene mutation profiles and the relationship between GAA and Pompe disease in Asian populations.

Unexpectedly High Prevalence of Coronary Spastic Angina in Patients With Anderson-Fabry Disease.

BACKGROUND: Although we and others have reported cases of patients with Anderson-Fabry disease (AFD) complicated by coronary spastic angina (CSA), the prevalence of CSA in these patients remains unknown. Methods and Results: We performed the acetylcholine-induced provocation test, according to the Japanese guidelines for the diagnosis and treatment of patients with CSA, in 9 consecutive patients having 5 independent AFD pedigrees. Coronary spasms were provoked in conjunction with symptoms and ECG ischemic changes in 8 of 9 (89%) patients with AFD. CONCLUSIONS: We found an unexpectedly high prevalence of CSA in patients with AFD.

High-risk screening for Gaucher disease in patients with neurological symptoms.

Gaucher disease (GD) is an autosomal recessive lysosomal storage disorder caused by the deficiency of glucocerebrosidase enzyme activity. Clinical phenotypes of GD are categorized into three groups: (i) non-neuronopathic GD (type 1), (ii) acute neuronopathic GD (type 2) and (iii) subacute neuronopathic GD (type 3). The high-risk screening of neuronopathic GD has been performed using an enzymatic assay on the dried blood spot (DBS) samples. We enrolled a total of 102 individuals (47 females, 55 males; 0-57 years old; median age 10.5 years) with various neurological symptoms. We detected two patients with very low enzyme activity and they were diagnosed with the disease by using glucocerebrosidase gene analysis. Patient 1 was found to be compound heterozygous for the p.R159W/p.R170C locus and patient 2 was found to harbor two mutations at the IVS7+1G>T (c.999+1G>T) and p.L483P sites. This simple screening protocol using DBS samples is useful for early diagnosis of GD in high-risk and underdiagnosed patients suffering from various neurological symptoms.

A Significant Difference in the Blood Carnitine Values Obtained by the Enzymatic Cycling and Tandem Mass Spectrometry Methods.

BACKGROUND: There are no reports in the literature of blood samples obtained from the same individual being subjected to analysis at the same time using the enzymatic cycling (EC) method along with electrospray tandem mass spectrometry (ESI/MS/MS) before and after carnitine treatment. METHODS: Blood samples from 29 patients (median age: 73 years old, age range: 41 - 89 years) receiving regular hemodialysis for chronic renal failure before and after carnitine treatment for 3 months were measured by the EC method, and using a dried blood spot (DBS) and ESI/MS/MS. RESULTS: Before the carnitine treatment, the rate of increase or decrease in the free and acyl-carnitine levels of the DBS using the ESI/MS/MS method to those measured by the EC methods was a median of -28.6% (-36.0 to -14.1%) and -20.8% (-30.0 to 1.5%), respectively. After carnitine treatment, the rate of increase or decrease in the free and acyl-carnitine levels of the DBS with the ESI/MS/MS method compared to the EC method was a median of 52.0% (28.4 to 66.7%) and -31.9% (-47.2 to -21.1%), respectively. CONCLUSIONS: There were significant differences in the blood carnitine values using the ESI/MS/MS and EC methods. Caution should be exercised when evaluating DBS values measured by the ESI/MS/MS method.

Early liver transplantation in neonatal-onset and moderate urea cycle disorders may lead to normal neurodevelopment.

Urea cycle disorders (UCDs) are inherited metabolic diseases that lead to hyperammonemia. Neurodevelopmental outcomes of patients with UCDs depend on the maximum ammonia concentration (MAC) in the blood during onset. MAC ≥360 µM is a marker of poor neurodevelopmental outcomes. We investigated the neurodevelopmental outcomes and MAC at onset for 177 patients with UCDs in Japan (median age, 8 years and 2 months; range, 10 days-72 years), including 57 patients with male ornithine transcarbamylase (OTCD), 59 patients with female OTCD, 23 patients with carbamoyl-phosphate synthetase 1 deficiency (CPSD), 28 patients with arginosuccinate synthetase deficiency, 9 patients with arginosuccinate lyase deficiency (ALD), and 1 patient with arginase 1 deficiency. Neurodevelopmental outcomes of patients with CPSD and ALD were poor because most had neonatal onset with blood MAC ≥300 µM at onset. Although OTCD, particularly female late-onset OTCD, has good neurodevelopmental outcomes among those with UCDs, it is not necessarily a mild disease with good long-term outcomes. Patients with severe UCDs and MAC ≥300 µM at onset should undergo liver transplantation (LT). Moreover, this study suggested that if the onset of UCD began during the neonatal period, then even UCD patients with MAC <300 µM at onset should undergo LT to protect the brain.

Prevalence of Fabry disease and GLA c.196G>C variant in Japanese stroke patients.

Fabry disease is an important underlying disease in young cryptogenic stroke patients. However, little is known regarding the frequency of Fabry disease in the general stroke population, especially in elderly patients. A total of 588 stroke patients (61.7% men; average age 74.1±12.5 years) were enrolled in this prospective study. Blood samples were obtained to produce blood spots to determine α-galactosidase A (α-GalA) activity and for GLA gene analysis. One 65-year-old female patient had a known GLA gene mutation, c.2T>C (p.M1T), causing Fabry disease. Five male patients and two female patients had GLA c.196G>C (p.E66Q) variant, which is not associated with the full clinical manifestations of Fabry disease. The allele frequency of GLA c.196G>C was significantly higher in male patients with small-vessel occlusion (odds ratio 3.95, P=0.048) and non-cardioembolism (odds ratio 4.08, P=0.012) than that in the general Japanese population. Fabry disease is rare in the general Japanese stroke population. However, screening identified one elderly female patient with Fabry disease. GLA c.196G>C variant is a genetic risk factor for cerebral small-vessel occlusion and non-cardioembolism in Japanese males but not in females.

Plasma exchange and chelator therapy rescues acute liver failure in Wilson disease without liver transplantation.

AIM: Wilson disease (WD) in patients with a New Wilson Index (NWI) score ≥ 11 is fatal, and these patients are good candidates for liver transplantation (LT). However, plasma exchange and chelator therapy are indispensable and effective even for WD with a score ≥ 11. Moreover, continuous hemodiafiltration (CHDF) with these treatments is essential for acute liver failure (ALF) in WD with hepatic encephalopathy because CHDF can exclude toxic metabolites that may cause damage to the brain. Here, we describe four rescued patients presenting with ALF in WD and discuss the available treatment options. METHODS: We have experienced 11 male and 8 female patients presenting with WD at the Department of Pediatrics, Kumamoto University Hospital between 1999 and 2014. A male and 4 female patients were diagnosed as WD with ALF using a combination of clinical findings and biochemical tests. RESULTS: The NWI score was ≥ 11 in cases 1 to 3. Cases 1 and 2 with hepatic encephalopathy received plasma exchange, CHDF, coagulation factor replacement treatment (CFRT) and LT. Cases 3 and 4 without encephalopathy obtained stable status without LT by plasma exchange, blood infusion, and CFRT. CONCLUSIONS: It is better to undergo LT for WD patients with a NWI score ≥ 11, however, there is a possibility of remission by plasma exchange and medical therapy even without LT. WD patients with a NWI score ≥ 11can be rescued by conservative therapy when the ALF of WD does not present with ALF and hepatic encephalopathy. Therefore, ALF with hepatic encephalopathy itself is an indication for LT in WD.

Liver transplantation may prevent neurodevelopmental deterioration in high-risk patients with urea cycle disorders.

UCDs are among the most common inherited metabolic diseases in Japan. We investigated the clinical manifestations, treatment, and prognoses of 177 patients with UCDs who were evaluated and treated from January 1999 to March 2009 in Japan, using a questionnaire survey. Among these 177 patients, 42 (seven with carbamoyl phosphate synthetase 1 deficiency, 27 with ornithine transcarbamylase deficiency, seven with argininosuccinate synthetase deficiency, and one with arginase 1 deficiency) underwent living-donor LT. Although this study was retrospective and included limited neurodevelopmental information before and after LT, we evaluated whether LT could improve neurodevelopmental outcomes in patients with UCDs. The neurodevelopmental outcomes of patients with a MAC of <300 µmol/L at the time of onset were not significantly different between the LT and non-LT groups (P=.222). LT may have prevented further neurodevelopmental complications in children with MAC ≥300 µmol/L (P=.008) compared with non-transplant management. Therefore, Liver transplant should be considered in patients with UCD with a MAC of ≥300 µmol/L at the time of disease onset.

Analysis of estrogen receptor ß gene methylation in autistic males in a Chinese Han population.

Autism spectrum disorder (ASD) is a neurodevelopment disorder with abnormalities of social interaction, communication and repetitive behaviors. The higher prevalence of ASD in men implies a potential relationship between sex hormones and ASD etiology. The ESR2 gene encodes estrogen receptor beta (ESR2) and plays an important role during brain development. A relationship between ESR2 and ASD has been suggested by studies on single nucleotide polymorphisms and mRNA and protein expression levels in ASD patients. Here, we explored the possible epigenetic regulation of the ESR2 gene in autism. We collected genomic DNA from the peripheral blood of Chinese Han males with autism and age-matched normal males and measured DNA methylation of CpG islands in the ESR2 gene, which consisted of 41 CpG sites among the proximal promoter region and an untranslated exon, by bisulfite sequencing. We also investigated a relationship between DNA methylation and phenotypic features of autism, as assessed by the Children Autism Rating Scale. We found little overall difference in the DNA methylation of the ESR2 5'-flanking region in individuals with autism compared with normal individuals. However, detailed analyses revealed that eight specific CpG sites were hypermethylated in autistic individuals and that four specific CpG sites were positively associated with the severity of autistic symptoms. Our study indicates that the epigenetic dysregulation of ESR2 may govern the development of autism.

Tyrosinemia Type I in Japan: A Report of Five Cases.

Tyrosinemia type I in Japan was reported for the first time in 1957 by Sakai et al. (Jikei Med J 2:1-10, 1957) and Kitagawa et al. (Proc Jpn Acad Ser B 88:192-200, 1957). Five cases of patients with tyrosinemia type I were reported to be definitively diagnosed in Japan. The first case was reported by Sakai et al. and Kitagawa et al. To the best of our knowledge, this was the first definite report in the world. The second and third cases were those of a brother and a sister who underwent liver transplantation and who were the children of a Japanese-descent migrant worker; the fourth case was that of a girl who underwent liver transplantation after 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) treatment, which was reported by Hata et al.; and the fifth case was that of a patient who was administered NTBC, which was reported by Ito et al. These were of the subacute type, wherein residual activity was considerably present. When combined therapy with a low phenylalanine and tyrosine diet and NTBC administration is started after early diagnosis, patients can survive without liver transplantation. Development of liver cancer is not found in the cases in Japan, but performing liver transplantation without delay is necessary when liver cancer is found.

Medically dependent severe motor and intellectual disabilities: Time study of medical care.

BACKGROUND: Improvements in neonatal medicine and pediatric emergency medicine have led to an increasing number of children with severe disabilities requiring medical care, such as tracheal suction, on a daily basis. Most of these children, discharged directly from hospitals to their parents' homes, need home medical support. To provide data for the establishment of appropriate support systems, we analyzed the care for such children in a time study conducted at an institution. METHODS: A minute-by-minute time study of the work of 33 staff members in a ward for patients (medically dependent severe motor and intellectual disabilities [SMID]) requiring frequent medical care was carried out over 48 h. Data were compared with those from a ward for ordinary non-medically dependent SMID patients. RESULTS: Time of life care for medically dependent SMID and ordinary SMID was almost identical, but the time for medical care for the former was 10-fold longer than that of the latter. Also, tasks involving information exchange and recording of the time of care were performed fourfold more frequently in the medically dependent SMID than in the ordinary SMID ward. CONCLUSIONS: Medically dependent SMID children and adults, predominantly with tracheostomies, needed much more medical care and more concentrated involvement of the staff compared with ordinary SMID. This study provides valuable data for the development of support systems for medically dependent SMID children being cared for at home. In addition, it sheds light on the situation faced by non-SMID children requiring frequent medical care.

Citrulline for urea cycle disorders in Japan.

BACKGROUND: The amino acid l-citrulline is used as a therapeutic agent for urea cycle disorders (UCD) including ornithine transcarbamylase deficiency (OTCD), carbamoyl phosphate synthetase I deficiency (CPSD), and N-acetylglutamate synthase deficiency. There are few reports, however, on the use of l-citrulline in Japan and little consensus regarding the effects of l-citrulline. METHODS: We conducted a questionnaire survey of patients undergoing l-citrulline treatment for a UCD to evaluate the current status of this therapy. The survey included patient background, details of l-citrulline treatment, clinical examination data, treatment, frequency of vomiting, and liver transplantation. RESULTS: We retrospectively investigated 43 questionnaire respondents (OTCD, n = 33; CPSD, n = 10). The weight of male OTCD patients improved by +0.79 SD, and the ammonia level decreased by a mean of 44.3 µmol/L in all patients. The protein intake of all patients and of male OTCD patients increased by 0.14 g/kg/day and 0.17 g/kg/day, respectively. CONCLUSIONS: l-Citrulline effectively reduced ammonia level, increased protein intake, and improved weight gain in UCD patients. l-Citrulline should be considered a standard therapy in OTCD and CPSD patients.

Amelioration by glycine of brain damage in neonatal rat brain following hypoxia-ischemia.

BACKGROUND: Glycine protected adult brains against injury in an experimental model of stroke, but, because the ischemic response of neonatal brains differs from that of adult brains, we examined the neuroprotective efficacy of glycine and associated mechanisms in an experimental model of neonatal hypoxic-ischemic (HI) encephalopathy. METHODS: Neonatal (postnatal day 7) Wistar rats were randomly divided into an untreated group (non-HI) and two HI groups that were treated with left common carotid artery ligation and saline control or glycine. After recovery, pups that received surgery were injected i.p. with saline or glycine (800 mg/kg; optimal dose determined in pilot experiments) and were placed in a controlled 8% O2 chamber for 120 min. Brains were harvested at various times after return to normoxia (several hours-days after HI) for analysis of infarct area, glial activation, cell apoptosis, and tumor necrosis factor-α (TNF-α) expression on histology and reverse transcription-polymerase chain reaction. RESULTS: Glycine injections induced large (approx. 15-fold) but brief (approx. 2 h) increases in cerebrospinal fluid concentrations. In particular, the glycine group had a >70% decrease in infarct areas compared with controls at 7 days after HI. Glycine also significantly reduced astrocyte reactive transformation, microglia activation, and terminal deoxynucleotidyl transferase dUTP nick end labeling-positive (apoptotic) cell numbers in peri-lesional areas at 3 days after HI, and TNF-α mRNA expression in the injured hemisphere at 12 and 24 h after HI. CONCLUSION: Glycine protected neonatal rat brains against HI, in part by inhibiting TNF-α-induced inflammation and gliosis. Hence, systemic glycine infusions may have clinical utility for the treatment of HI injury in human newborns.

Mechanism for increased hepatic glycerol synthesis in the citrin/mitochondrial glycerol-3-phosphate dehydrogenase double-knockout mouse: Urine glycerol and glycerol 3-phosphate as potential diagnostic markers of human citrin deficiency.

The mitochondrial aspartate-glutamate carrier isoform 2 (citrin) and mitochondrial glycerol-3-phosphate dehydrogenase (mGPD) double-knockout mouse has been a useful model of human citrin deficiency. One of the most prominent findings has been markedly increased hepatic glycerol 3-phosphate (G3P) following oral administration of a sucrose solution. We aimed to investigate whether this change is detectable outside of the liver, and to explore the mechanism underlying the increased hepatic G3P in these mice. We measured G3P and its metabolite glycerol in plasma and urine of the mice under various conditions. Glycerol synthesis from fructose was also studied using the liver perfusion system. The citrin/mGPD double-knockout mice showed increased urine G3P and glycerol under normal, fed conditions. We also found increased plasma glycerol under fasted conditions, while oral administration of different carbohydrates or ethanol led to substantially increased plasma glycerol. Fructose infusion to the perfused liver of the double-knockout mice augmented hepatic glycerol synthesis, and was accompanied by a concomitant increase in the lactate/pyruvate (L/P) ratio. Co-infusion of either pyruvate or phenazine methosulfate, a cytosolic oxidant, with fructose corrected the high L/P ratio, leading to reduced glycerol synthesis. Overall, these findings suggest that hepatic glycerol synthesis is cytosolic NADH/NAD(+) ratio-dependent and reveal a likely regulatory mechanism for hepatic glycerol synthesis following a high carbohydrate load in citrin-deficient patients. Therefore, urine G3P and glycerol may represent potential diagnostic markers for human citrin deficiency.

Clinical manifestations and growth of patients with urea cycle disorders in Japan.

We have previously examined the clinical manifestations, treatments and prognosis of 177 patients with urea cycle disorders (UCDs) from January 1999 to March 2009 in Japan. In this study, we investigated the incidence of clinical manifestations in different peak blood ammonia level at onset in UCD patients, and examined the growth of OTCD (ornithine transcarbamylase deficiency) patients. The UCD patients who had a high peak blood ammonia level at onset showed significantly high incidence of convulsion and abnormal head computed tomography or magnetic resonance imaging. The patients also showed significantly high incidence of hemodialysis and liver transplantation. Choice of therapeutic agents for long-term treatment is not different between peak blood ammonia levels at the onset, except for the use of special amino-acid formulas. Growth retardation is not affected by high peak blood ammonia level at onset; however, 32% of male and 52% of female OTCD patients over 1 year old were plotted under the 10th percentile, and showed growth failure. The final height of the male and female OTCD patients were 166.2±5.5 and 150.3±7.2 cm, respectively. Although the prognosis of UCDs was improved significantly, it is considered that there are still many difficulties in the UCD patient's life.