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OBJECTIVE: To compare the clinical and genetic characteristics of patients with neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) and idiopathic neonatal cholestasis (INC). METHODS: The clinical data of 30 patients with NICCD and 30 patients with INC admitted in Children’s Hospital of Chongqing Medical University during September 2012 and December 2017 were retrospectively analyzed. The clinical manifestations, biochemical indicators and genetic characteristics were compared between two groups. RESULTS: Patients in both groups presented similar clinical manifestations, however the chubby face and clay-colored stool were more common in NICCD patients (both PA and c.919G>T were two novel mutations. CONCLUSIONS: The manifestations of chubby face and clay-colored stool may provide clue for early diagnosis of NICCD along with the elevated biochemical parameters, such as ammonium, alpha-fetal protein, citrulline in blood and 4-hydroxyphenyllactic acid, 4-hydroxyphenylpyruvic acid, phenyllactic acid in urine. Target gene trapping and high-throughput sequencing have the key values in diagnosis and differential diagnosis of NICCD.

Citrin deficiency is characterized by a wide range of symptoms from infancy through adulthood and presents a distinct preference for a diet composed of high protein, high fat, and low carbohydrate. The present study elucidates the important criteria by patients with citrin deficiency for food selection through detailed analysis of their food preferences. The survey was conducted in 70 citrin-deficient patients aged 2–63 years and 55 control subjects aged 2–74 years and inquired about their preference for 435 food items using a scale of 1–4 (the higher, the more favored). The results showed that the foods marked as “dislike” accounted for 36.5% in the patient group, significantly higher than the 16.0% in the controls. The results also showed that patients clearly disliked foods with 20–24 (% of energy) or less protein, 45–54% (of energy) or less fat, and 30–39% (of energy) or more carbohydrate. Multiple regression analysis showed carbohydrates had the strongest influence on patients’ food preference (β = −0.503). It also showed female patients had a stronger aversion to foods with high carbohydrates than males. The protein, fat, and carbohydrate energy ratio (PFC) of highly favored foods among patients was almost the same as the average PFC ratio of their daily diet (protein 20–22: fat 47–51: carbohydrates 28–32). The data strongly suggest that from early infancy, patients start aspiring to a nutritional balance that can compensate for the metabolism dissonance caused by citrin deficiency in every food.

To evaluate the feasibility of incorporating genetic screening for neonatal intrahepatic cholestasis, caused by citrin deficiency (NICCD), into the current newborn screening (NBS) program. We designed a high-throughput iPLEX genotyping assay to detect 28 SLC25A13 mutations in the Chinese population. From March 2018 to June 2018, 237 630 newborns were screened by tandem mass spectrometry at six hospitals. Newborns with citrulline levels between 1/2 cutoff and cutoff values of the upper limit were recruited for genetic screening using the newly developed assay. The sensitivity and specificity of the iPLEX genotyping assay both reached 100% in clinical practice. Overall, 29 364 (12.4%) newborns received further genetic screening. Five patients with conclusive genotypes were successfully identified. The most common SLC25A13 mutation was c.851_854del, with an allele frequency of 60%. In total, 658 individuals with one mutant allele were identified as carriers. Eighteen different mutations were observed, yielding a carrier rate of 1/45. Notably, Quanzhou in southern China had a carrier rate of up to 1/28, whereas Jining in northern China had a carrier rate higher than that of other southern and border cities. The high throughput iPLEX genotyping assay is an effective and reliable approach for NICCD genotyping. The combined genetic screening could identify an additional subgroup of patients with NICCD, undetectable by conventional NBS. Therefore, this study demonstrates the viability of incorporating genetic screening for NICCD into the current NBS program.

PurposeAccurate profiling of population-specific recessive diseases is essential for the design of cost-effective carrier screening programs. However, minority populations and ethnic groups, including Vietnamese, are still under-represented in existing genetic studies. Here we reported the first comprehensive study of recessive diseases in the Vietnamese population.MethodsClinical exome sequencing (CES) data of 4,503 disease-associated genes obtained from a cohort of 985 Vietnamese individuals was analyzed to identify pathogenic variants, associated diseases and their carrier frequencies in the population.ResultsEighty-five recessive diseases were identified in the Vietnamese population, among which seventeen diseases had carrier frequencies of at least 1% (1 in 100 individuals). Three diseases were especially prevalent in the Vietnamese population with carrier frequencies of 2-12 times higher than in other East Asia or the world populations, including Beta-thalassemia (1 in 25), citrin deficiency (1 in 33) and phenylketonuria (1 in 40). Seven novel pathogenic and three likely pathogenic variants associated with nine recessive diseases were also discovered.ConclusionsThe comprehensive profile of recessive diseases identified in this study shall enable the design of cost-effective carrier screening programs specific to the Vietnamese population. The newly discovered pathogenic variants may also exist in other populations at extremely low frequencies, thus representing a valuable resource for future research. Our study has demonstrated the advantage of population-specific genetic studies to advance the knowledge and practice of medical genetics.

Citrin deficiency caused by SLC25A13 genetic mutations is an autosomal recessive disease, and four prevalent mutations including c.851_854del, c.1638_1660dup, IVS6+5G>A, and IVS16ins3kb make up >80% of total pathogenic mutations within the Chinese population. However, suitable assays for detection of these mutations have not yet been developed for use in routine clinical practice. In the current study, a real-time PCR-based multicolor melting curve analysis (MMCA) was developed to detect the four prevalent mutations in one closed-tube reaction. The analytical and clinical performances were evaluated using artificial templates and clinical samples. All four mutations in the test samples were accurately genotyped via their labeling fluorophores and Tm values, and the standard deviations of Tm values were indicated to be SLC25A13-mutation carriers, indicating a carrier rate of 2%. The genotypes of 107 carriers and 112 random non-carriers were validated using direct sequencing and Long-range PCR with 100% concordance. In conclusion, the assay developed in this study may potentially serve as a rapid genetic diagnostic tool for citrin deficiency.

Urea cycle disorders (UCDs) are a group of rare metabolic conditions characterized by hyperammonemia and a broad spectrum of phenotypic severity. They are caused by the congenital deficiency in the eight biomolecules involved in urea cycle. In the present study, five cases of UCD were recruited and submitted to a series of clinical, biochemical, and genetic analysis with a combination of high throughput techniques. Moreover, in silico analysis was conducted on the identified missense genetic variants. Various clinical and biochemical indications (including profiles of amino acids and urinary orotic acids) of UCD were manifested by the five probands. Sequence analysis revealed nine diagnostic variants, including three novel ones, which caused Argininosuccinic aciduria (ASA) in one case, Carbamoyl phosphate synthetase 1deficiency (CPS1D) in two cases, Ornithine transcarbamylase deficiency (OTCD) in one case, and Citrin deficiency in 1case. Results of in silico biophysical analysis strongly suggested the pathogenicity of each the five missense variants and provided insight into their intramolecular impacts. In conclusion, this study expanded the genetic variation spectrum of UCD, gave solid evidence for counselling to the affected families, and should facilitate the functional study on the proteins in urea cycle.

Amaç: Kalıtsal metabolik hastalıklar (KMH), insan biyokimyasal yolaklarında görev alan tüm moleküllerin kalıtsal bozukluklarını kapsayan oldukça geniş bir hastalık grubudur. Tedavi edilme potansiyelleri ile öne çıkan KMH’lar, ilk bulgularını erişkin yaşta da verebilirler. Bu çalışma ile kliniğimizde erişkin yaşta kalıtsal metabolik hastalık tanısı alan olguların klinik fenotipleri ve tanısal özellikleri derlenerek, bu konuda farkındalık yaratılması amaçlanmıştır. Gereç ve yöntem: Erişkin yaşta KMH tanısı almış olguların dosyaları geriye dönük olarak incelenmiştir. Bulgular: Yaşları 19-88 yıl arasında değişen, 14 aileden 39 erişkin olguya 9 özgül KMH tanısı konulmuştur; Fabry Hastalığı (%59), Sitrin eksikliği (%10), Multipl açil-KoA dehidrogenaz eksikliği (%8), Alkaptonüri (%8), Adrenolökodistrofi (%5), ve birer olgu ile Akut intermitan porfiri, Serebral kreatin transport bozukluğu, Mitokondriyal nörogastrointestinal ensefalomiyelopati, Ornitin transkarbamilaz eksikliği. Olguların %80’i aile taramasında, %18’i klinik bulgularla, %2’si selektif tarama ile tanı almıştır. Tanı esnasında olguların %77‘si semptomatik, %23’ü asemptomatiktir. Semptomatik olguların hastanede ilk başvurdukları klinikler nöroloji (%30), nefroloji (%14), göğüs hastalıkları (%14), ortopedi (%10), dahiliye (%7) ve kardiyolojidir (%7). Semptomatik olguların %60’ına KMH tanısı biyokimyasal testler ile konulmuştur. Olgularımızın %93’ü için hastalığa spesifik tedavi mevcut olup, ancak takipsizlik ya da tedavi reddi nedeniyle sadece %67’sine tedavi uygulanabilmiştir. Sonuç: Erişkin başlangıçlı kalıtsal metabolik hastalıklar konusunda farkındalığın artması hastaların erken tedavi olmalarını sağlayarak morbidite ve mortaliteyi azaltacaktır. Kalıtsal metabolizma hastalıkları alanında özelleşmiş erişkin branş hekimlerinin yetişmesine ihtiyaç vardır. Purpose: Inherited metabolic diseases (IMDs), are genetic diseases of human biochemical pathways and can present at adulthood. IMDs, which stand out for their potential to be treated, can also make their first findings in adulthood. In this study, we aimed to document clinical and diagnostic features of the patients with adult onset IMDs in our clinic and to raise awareness on this subject. Materials and methods: Medical files of patients diagnosed with IMD at adulthood were retrospectively analyzed. Results: 39 adult cases from 14 families, aged between 19-88 years, were diagnosed with 9 specific IMDs; Fabry disease (59%), Citrin deficiency (10%), Multiple acyl-CoA dehydrogenase deficiency (8%), Alkaptonuria (8%), Adrenoleukodystrophy (5%), and Acute hepatic porphyria, Cerebral creatine transport defect, Mitochondrial neurogastrointestinal encephalomylopathy, Ornithine transcarbamylase deficiency. The cases were diagnosed with family screening in 80%, clinical findings in 18%, and selective screening in 2%. 77% of the cases were symptomatic and 23% were asymptomatic at the time of diagnosis. The outpatient clinics where the symptomatic patients had first admitted were neurology (30%), nephrology (14%), chest diseases (14%), orthopedics (10%), internal medicine (7%) and cardiology (7%). In symptomatic cases, the diagnosis of IMD was made by biochemical tests in 60%. Disease-specific treatments were available for 93%, but 67% were treated due to patient refusal of treatment or lost to follow-up. Conclusion: Morbidity and mortality related to adult-onset inherited metabolic diseases can be reduced, by increasing awareness and timely management. There is a need for dedicated physicians, trained to diagnose and manage adult patients with IMDs.

Background Citrin deficiency (CD) is a recessive metabolic disease caused by biallelic pathogenic variants in SLC25A13. Although previous studies have reported ketosis in CD, it was observed at the time of euglycemia or mild hypoglycemia. Blood ketone levels concomitant with symptomatic or severe hypoglycemia in CD have not been a topic of focus despite its importance in identifying the etiology of hypoglycemia and assessing the ability of fatty acid utilization. Herein, we describe a patient with CD who had repeated episodes of hypoglycemia with insufficient ketosis. Case presentation A 1-year-old boy with repetitive hypoglycemia was referred to us to investigate its etiology. The fasting load for 13 h led to hypoketotic hypoglycemia, indicating the possibility of partial β-oxidation dysfunction. A genetic test led to the diagnosis of CD. The hypoglycemic episodes disappeared after switching to a medium-chain triglyceride-containing formula. Conclusions This case report suggests that symptomatic or severe hypoglycemia in patients with CD could be associated with relatively low levels of ketone bodies, implying that β-oxidation in these patients might possibly be partially disrupted. When encountering a patient with hypoglycemia, clinicians should check blood ketone levels and bear in mind the possibility of CD because excessive intravenous administration of glucose can cause decompensated symptoms in patients with CD as opposed to other disorders presenting with hypoketotic hypoglycemia, such as fatty acid oxidation disorders. Further studies in a large-scale cohort are warranted to confirm our speculation.

Background Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) has high prevalence in East Asia, and has been reported in other parts of the world. NICCD is also the most common form of genetic cholestasis among East Asians. There has been reports of mortalities or liver transplants associated with NICCD, but risk factors associated with poor outcome were unknown. Our objective is to report NICCD mortalities in a tertiary pediatric hepatology center, and to explore associated risk factors along with implications to clinical practice. Method This is a retrospective analysis of NICCD cases collected from June 2003 until January 2017 in the Children’s Hospital of Fudan University. Clinical, biochemical, and genetic data were compared between deceased cases and survivors without liver transplant. Results Sixty-one confirmed NICCD cases, including 52 cases in the survival group, and 9 cases in the mortality group, were included in the analysis. Mean age at referral in the mortality group was significantly higher when compared to the survival group (9.58 ± 5.03 VS 3.96 ± 3.13 months, p

Citrin deficiency is a recessively inherited metabolic disorder with age-dependent clinical manifestations. It causes neonatal intrahepatic cholestasis (NICCD) and adult-onset type II citrullinemia (CTLN2). Patients with NICCD present with intrahepatic cholestasis in the neonatal period and usually respond to the treatment with medium-chain triglyceride (MCT) supplement and lactose-restricted formula. In adulthood, CTLN2 develops in

Background and objectives: This retrospective study analysed a case series of subjects with citrin deficiency, and aims to present the molecular and clinical characterization of this disease in the Hong Kong Chinese population for the first time. Patients and Methods: Data from medical records of eighteen patients with citrin deficiency (years 2006–2015) were retrieved. Demographic data, biochemical parameters, radiological results, genetic testing results, management, and clinical outcome were collected and analysed. Results: Eighteen patients with diagnosis of citrin deficiency were recruited. All 18 patients carried at least one common pathogenic variant c.852_855delTATG in SLC25A13. Prolonged jaundice (neonatal intrahepatic cholestasis caused by citrin deficiency, NICCD) was the most common presenting symptom, in conjunction with elevated plasma citrulline, threonine, alkaline phosphatase, and alpha-fetoprotein levels. The abnormal biochemical parameters including liver derangement returned to normal range in most of the cases by 6 months of age after the introduction of a lactose-free formula. There were a few cases with atypical presentations. Two subjects did not present with NICCD, and were subsequently diagnosed later in life after their siblings presented with symptoms of citrin deficiency at one month of age and subsequently received a molecular diagnosis. One patient with citrin deficiency also exhibited multiple liver hemangioendotheliomas, which subsided gradually after introduction of a lactose-free formula. Only one patient from this cohort was offered expanded metabolic screening at birth. She was not ascertained by conducted newborn screening and was diagnosed upon presentation with cholestatic jaundice by 1 month of age. Conclusion: This is the first report of the clinical and molecular characterization of a large cohort of patients with citrin deficiency in Hong Kong. The presentation of this cohort of patients expands the clinical phenotypic spectrum of NICCD. Benign liver tumors such as hemangioendotheliomas may be associated with citrin deficiency in addition to the well-known association with hepatocellular carcinoma. Citrin deficiency may manifest in later infancy period with an NICCD-like phenotype. Furthermore, this condition is not always ascertained by expanded newborn metabolic screening testing. Keywords: Citrin deficiency, NICCD, FTTDCD, CTLN2, Hemangioendothelioma

// Zhan-Hui Zhang 1, * , Wei-Xia Lin 2, * , Qi-Qi Zheng 2 , Li Guo 2 and Yuan-Zong Song 2 1 Clinical Medicine Research Institute, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China 2 Department of Pediatrics, The First Affiliated Hospital, Jinan University, Guangzhou 510630, China * These authors have contributed equally to this study Correspondence to: Yuan-Zong Song, email: songyuanzong@hotmail.com, songyuanzong@vip.tom.com Keywords: citrin deficiency, intrahepatic cholestasis, SLC25A13 , mutation, Western blotting Received: December 06, 2016 Accepted: July 18, 2017 Published: August 03, 2017 ABSTRACT Neonatal Intrahepatic Cholestasis caused by Citrin Deficiency (NICCD) arises from biallelic SLC25A13 mutations, and SLC25A13 analysis provides reliable evidences for NICCD definite diagnosis. However, novel large insertions/deletions in this gene could not be detected just by conventional DNA analysis. This study aimed to explore definite diagnostic evidences for an infant highly-suspected to have NICCD. Prevalent mutation screening and Sanger sequencing of SLC25A1 3 gene just revealed a paternally-inherited mutation c.851_854del4. Nevertheless, neither citrin protein nor SLC25A13 transcripts of maternal origin could be detected on Western blotting and cDNA cloning analysis, respectively. On this basis, the hidden maternal mutation was precisely positioned using SNP analysis and semi-quantitative PCR, and finally identified as a novel large deletion c.-3251_c.15+18443del21709bp, which involved the SLC25A13 promoter region and the entire exon 1 where locates the translation initiation codon. Hence, NICCD was definitely diagnosed in the infant. To the best of our knowledge, the novel gross deletion, which silenced the transcriptional and translational expression of the affected SLC25A13 allele, is the hitherto largest deletion in SLC25A13 mutation spectrum. The Western blotting approach using mitochondrial protein extracted from expanded peripheral blood lymphocytes, of particular note, might be a new minimally-invasive and more-feasible molecular tool for NICCD diagnosis.

Sodium taurocholate cotransporting polypeptide (NTCP), a carrier protein encoded by the gene SLC10A1, is expressed in the basolateral membrane of the hepatocyte to uptake bile acids from plasma. As a new inborn error of bile acid metabolism, NTCP deficiency remains far from being well understood in terms of the clinical and molecular features. Citrin deficiency is a well-known autosomal recessive disease arising from SLC25A13 mutations, and in neonates or infants, this condition presents as transient intrahepatic cholestasis which usually resolves before 1 year of age. All the three patients in this paper exhibited cholestatic jaundice and elevated total bile acids in their early infancy, which were attributed to citrin deficiency by SLC25A13 genetic analysis. In response to feeding with lactose-free and medium-chain triglycerides-enrich formula, their clinical and laboratory presentations disappeared gradually while the hypercholanemia persisted, even beyond 1 year of age. On subsequent SLC10A1 analysis, they were all homozygous for the well-known pathogenic variant c.800C > T (p.Ser267Phe), and NTCP deficiency was thus definitely diagnosed. The findings in this paper indicated that NTCP deficiency could be covered up by citrin deficiency during early infancy; however, in citrin-deficient patients with intractable hypercholanemia following resolved cholestatic jaundice, NTCP deficiency should be taken into consideration.

Citrin deficiency initially presents as neonatal intrahepatic cholestasis (NICCD) and often resolves within first year of infancy. Failure to thrive and dyslipidemia caused by citrin deficiency (FTTDCD) has been recently proposed as a novel post-NICCD phenotype and its clinical features are still being established. Herein, we encountered a 2-year-old girl who was hospitalized for intermittent fever lasting 10 days. Besides pneumonia, we observed an NICCD-like phenotype with the presence of liver dysfunction, dyslipidemia, aminoacidemia, organic academia, and extremely high levels of alpha-fetoprotein (AFP). Genetic testing confirmed the diagnosis of citrin deficiency and, liver histology revealed she had already developed cirrhosis. Although, improvement of biochemical parameters and liver histology were observed after treatment that included dietary restrictions and symptomatic treatments, AFP levels remained elevated (>400 ng/ml) during a 3-year follow-up period. Moreover, liver magnetic resonance imaging (MRI) examination performed on the patient at age 5 revealed the development of multiple liver nodules with diffusion restriction on diffusion-weighted imaging (DWI). These observations highly indicate the possibility of hepatocellular carcinoma (HCC). Thus, this case reveals that an NICCD-like phenotype complicated with cirrhosis can exist during FTTDCD stage without any prior signs. It also emphasizes the necessity of monitoring AFP levels during follow-up for citrin deficiency patients with persistently high AFP level after treatment as FTTDCD may progress to HCC. Individualized treatment strategy for patients with FTTDCD also need to be explored.

Mutations in the solute carrier family 25 (SLC25A13) gene may result in neonatal intrahepatic cholestasis caused by citrin deficiency and/or adult-onset type II citrullinemia. These conditions are inherited in an autosomal recessive manner. The current case report describes a 43-year-old man who presented with sudden delirium and upper limb weakness. Upon admission, the patient was fully conscious and alert but later lost consciousness subsequent to a sudden convulsive seizure. Hyperammonemia was detected and analysis of the SLC25A13 gene identified an 851del4 mutation. Thus, the possibility of genetic disease should be considered as a potential cause of the symptoms of patients with altered states of consciousness, such as delirium and loss of consciousness, in cases where the cause of the disturbance is unknown.

Background: Little is known about the optimal dietary treatment for citrin deficiency. Our aim is to describe the management of UK citrin deficiency patients. Methods: A longitudinal retrospective review was performed. Data were collected from medical records on presenting signs and symptoms, dietary management and clinical outcome. Results: data were collected on 32 patients from 21 families. 50% were females (16/32). Median age at diagnosis was 4 y (5 days&ndash, 35 y) with 12 patients diagnosed in the neonatal period with neonatal intrahepatic cholestasis (NICCD), eight later in childhood (FTTDCD) and 12 by family screening based on index cases from five families. No patient had adult-onset type II citrullinemia. The patient age at the time of data collection was a median of 11 y (1&ndash, 44 y). 91% (29/32) of patients had normal physical and neurological development, 47% (15/32) experienced recurrent unexplained abdominal pain and 9% (3/32) episodes of hypoglycaemia. Siblings had different phenotypes (5 families had &gt, 1 affected patient). Most patients preferred high protein foods, limiting sugar-containing foods. Only 41% (13/32) were prescribed a low CHO, high protein, high fat diet (restriction varied) and two used medium chain triglyceride (MCT) supplements. No patient was prescribed drug therapy. Twenty-five per cent (8/32) of patients were underweight and 41% (13/32) had height &lt, &minus, 1 z-scores. Conclusions: patients presented with various phenotypes, symptoms and suboptimal growth. Symptoms and biochemical markers improved with age, but height remained low in some. More research is necessary to assess the effectiveness of dietary approaches in improving clinical outcomes and symptoms in citrin deficiency.

Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), failure to thrive and dyslipidemia (FTTDCD), and adult-onset type II citrullinemia (CTLN2). Owing to a defect in the NADH-shuttle, citrin deficiency impairs hepatic glycolysis and de novo lipogenesis leading to hepatic energy deficit. To investigate the physiological role of citrin, we studied the growth of 111 NICCD-affected subjects (51 males and 60 females) and 12 NICCD-unaffected subjects (five males and seven females), including the body weight, height, and genotype. We constructed growth charts using the lambda-mu-sigma (LMS) method. The NICCD-affected subjects showed statistically significant growth impairment, including low birth weight and length, low body weight until 6 to 9 months of age, low height until 11 to 13 years of age, and low body weight in 7 to 12-year-old males and 8-year-old females. NICCD-unaffected subjects showed similar growth impairment, including low birth weight and height, and growth impairment during adolescence. In the third trimester, de novo lipogenesis is required for deposition of body fat and myelination of the developing central nervous system, and its impairment likely causes low birth weight and length. The growth rate is the highest during the first 6 months of life and slows down after 6 months of age, which is probably associated with the onset and recovery of NICCD. Adolescence is the second catch-up growth period, and the proportion and distribution of body fat change depending on age and sex. Characteristic growth impairment in citrin deficiency suggests a significant role of citrin in the catch-up growth via lipogenesis.

Biallelic mutations of the SLC25A13 gene result in citrin deficiency (CD) in humans. Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is the major CD phenotype in pediatrics; however, knowledge on its genotypic and phenotypic characteristics remains limited. The present study aimed to explore novel molecular and clinical characteristics of CD. An infant suspected to have NICCD as well as her parents were enrolled as the research subjects. SLC25A13 mutations were investigated using various methods, including cDNA cloning and sequencing. The pathogenicity of a novel mutation was analyzed bioinformatically and functionally with a yeast model. Both the infant and her father were heterozygous for c.2T>C and c.790G>A, while the mother was only a c.2T>C carrier. The novel c.790G>A mutation proved bioinformatically and functionally pathogenic. The infant had esophageal atresia and an accessory hepatic duct, along with bile plug formation confirmed by laparoscopic surgery. However, the father seemed to be healthy thus far. The findings of the present study enrich the genotypic and phenotypic characteristics of CD patients, and provided clinical and molecular evidence suggesting the possible non-penetrance of SLC25A13 mutations and the likely involvement of this gene in primitive foregut development during early embryonic life.

Citrin-deficient children and adolescents between adult-onset type II citrullinemia and neonatal intrahepatic cholestasis by citrin deficiency do not have clear clinical features except for unusual diet of high-fat, high-protein, and low-carbohydrate food. The aims of the present study are to characterize fatigue and quality of life (QOL) in citrin-deficient patients during adaptation and compensation stage, and to define the relationship between fatigue and QOL. The study subjects were 55 citrin-deficient patients aged 1-22years (29 males) and 54 guardians. Fatigue was evaluated by self-reports and proxy-reports of the PedsQL Multidimensional Fatigue Scale. QOL was evaluated by the PedsQL Generic Core Scales. Both scale scores were significantly lower in child self-reports (p0.01 and p0.05, respectively) and parent proxy-reports (p0.01 and p0.01, respectively) than those of healthy children. Citrin-deficient patients with scores of 50 percentile or less of healthy children constituted 67.5% of the sample for the Fatigue Scale and 68.4% for the Generic Core Scales. The PedsQL Fatigue Scale correlated with the Generic Core Scales for both the patients (r=0.56) and parents reports (r=0.71). Assessments by the patients and their parents showed moderate agreement. Parents assessed the condition of children more favorably than their children. The study identified severe fatigue and impaired QOL in citrin-deficient patients during the silent period, and that such children perceive worse fatigue and poorer QOL than those estimated by their parents. The results stress the need for active involvement of parents and medical staff in the management of citrin-deficient patients during the silent period.

Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is characterized by conjugated hyperbilirubinemia and increased plasma bile acid concentrations. However, the underlying mechanisms remain unclear. We established a liquid chromatography tandem mass spectrometry (LC-MS/MS) method for simultaneously quantifying plasma bile acids and examined bile acid profiles in NICCD infants.We measured 15 bile acids within 15min and found a wide linear range for individual bile acids.The within-run and run-to-run CV of all bile acids was 1.2-10.9% and 3.1-10.8%, respectively, with a mean recovery of 90.5-112.6%. Compared to infants with citrullinemia without mutations in SLC25A13 (non-NICCD), NICCD infants showed increased plasma total bile acid concentrations (mean: 201 vs. 42μM, p0.001), with a distinct bile acid profile characterized by increased conjugated primary bile acid concentrations. The calculated ratios, including primary/secondary bile acid (714 vs. 235, p0.05) and conjugated/free bile acid (371 vs. 125, p0.05) ratios, were higher in NICCD infants. The area under receiver operating characteristic curve for conjugated/free bile acid ratio to identify infants with NICCD was 0.871 (95% confidence interval, 0.713-1.0).Together, our findings indicated plasma bile acid profile as a potential noninvasive diagnostic biomarker for NICCD.

Citrin is the liver-specific isoform of the mitochondrial aspartate/glutamate carrier (AGC2). AGC2 deficiency is an autosomal recessive disorder with two age related phenotypes: neonatal intrahepatic cholestasis (NICCD, OMIM#605814) and adult-onset type II citrullinemia (CTLN2, OMIM#603471). NICCD arises within the first few weeks of life resulting in prolonged cholestasis and metabolic abnormalities including aminoacidemia and galactosuria. Usually symptoms disappear within the first year of life, thus making a diagnosis difficult after this time. In this study we report a new Caucasian case of NICCD, a seven week old Romanian boy with prolonged jaundice. Sequencing of the AGC2 gene showed a novel homozygous missense double-nucleotide (doublet) mutation, which produces the change of the glycine at position 437 into glutamate. Functional studies, carried out on the recombinant mutant protein, for the first time demonstrated, that NICCD is caused by a reduced transport activity of AGC2. The presence of AGC2 deficiency in other ethnic groups besides Asian population suggests further consideration for NICCD diagnosis of any neonate with an unexplained cholestasis; a prompt diagnosis is crucial to resolve the metabolic decompensation with an appropriate dietary treatment.

Etiology determination of neurodevelopmental disabilities (NDDs) currently remains a worldwide common challenge on child health. We herein reported the etiology distribution feature in a cohort of 285 Chinese patients with NDDs. Although concrete NDD etiologies in 48.4% of the total patients could not be identified, genetic diseases (with the proportion of 35.8% in the total cases) including inborn errors of metabolism (IEM) and congenital dysmorphic diseases, constituted the commonest etiology category for NDDs in this study. The two key experimental technologies in pediatric metabolomics, gas chromatography-mass spectrometry (GC-MS), and tandem mass spectrometry (MS-MS), proved to be substantially helpful for the exploration of the NDD etiologies in this clinical investigation. The findings in this paper provided latest epidemiologic information on the etiology distribution of NDDs in Chinese, and the syndromic NDDs caused by citrin deficiency and the novel chromosomal karyotype, respectively, further expanded the etiology spectrum of NDDs.

SLC25A13 gene mutations cause citrin deficiency, which leads to neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD). Information on the mutation spectrum of SLC25A13 in the Chinese population is limited. The aim of this study was to explore the mutation spectrum of the SLC25A13 gene in Chinese infants with intrahepatic cholestasis and various forms of aminoacidemia.Sequence analyses were performed on 39 infants with intrahepatic cholestasis and various forms of aminoacidemia. Novel mutations were subjected to homology and structural analyses. Western blots were performed when liver specimens available.Genetic testing revealed the presence of SLC25A13 gene mutations (9 heterozygotes, 6 homozygotes and 13 compound heterozygotes) in 28 infants. Subsequent Western blot analysis revealed 22 cases of citrin deficiency, accounting for 56.4% of the 39 patients. Twelve types of mutations, including nine known mutations and three novel mutations, were found. Of the 49 mutated alleles, known ones include 851del4 (26 alleles, 53.1%), 1638ins23 (6 alleles, 12.2%), IVSl6ins3kb (3 alleles, 6.1%), IVS6+5GA (2 alleles, 4.1%), E601K (2 alleles, 4.1%) and IVS11+1GA, R184X, R360X and R585H (1 allele each, 2.0%). The three novel mutations were a splice site change (IVS6+1GA), a deletion mutation (1092_1095delT) and a missense mutation (L85P), each in one allele.The mutation spectrum of the SLC25A13 gene in a Chinese population of infants with intrahepatic cholestasis with various forms of aminoacidemia was found to be different from that of other population groups in East Asia. The SLC25A13 gene mutation is the most important cause of infantile intrahepatic cholestasis with various forms of aminoacidemia.

In this paper, we describe the historical aspects of citrin and citrin deficiency, characteristic food preference and food aversion of citrin-deficient subjects, and carbohydrate toxicity in relation to ureogenesis and issues of the conventional treatment procedures for hyperammonemia in citrin deficiency, leading to current treatment concepts for citrin deficiency. We also emphasize the importance of a citrin deficiency mouse model in elucidating the pathophysiology and developing novel therapeutics based on the pathophysiology, such as sodium pyruvate.

Citrin deficiency caused by SLC25A13 gene mutations develops into adult-onset type II citrullinemia (CTLN2) presenting with hepatic encephalopathy. Recent studies have suggested that excessive loading of carbohydrates is harmful in citrin-deficient individuals. Here we report a CTLN2 patient who showed further deterioration of encephalopathy after the employment of conventional low-protein diet therapy for chronic liver failure. Owing to the high carbohydrate content, the conventional low-protein diet therapy should be avoided in patients with hepatic encephalopathy associated with citrin deficiency. In addition, our observation may suggest that carbohydrate-restricted diet in which the content of carbohydrate is below 50% of daily energy intake can have therapeutic efficacy in CTLN2 patients., Article, INTERNAL MEDICINE. 49(3):243-247 (2010)

Citrin deficiency is a disorder with two phenotypes: neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and adult-onset type II citrullinaemia (CTLN2). NICCD presents in the first few weeks of life with prolonged cholestasis and metabolic abnormalities including aminoacidaemia (notably citrulline, tyrosine, threonine, arginine and methionine) and galactosuria. Symptoms resolve within the first year of life, thus making a diagnosis difficult after this time. Although patients subsequently remain generally healthy, some may develop more severe symptoms of CTLN2, characterized by neurological changes, one or more decades later. To date more than 400 cases have been reported, almost all from East Asia (mainly Japan). Here we describe the first two cases of NICCD in infants from the UK, one of caucasian origin and one of Pakistani origin. Both showed typical clinical and biochemical changes with a diagnosis confirmed by the presence of previously unreported mutations in the SLC25A13 gene. The presence of citrin deficiency in other ethnic groups means that NICCD needs to be considered in the diagnosis of any neonate with an unexplained cholestasis. We discuss both the difficulties in diagnosing these patients in populations where very few DNA mutations have been identified and the problems faced in the management of these patients. These findings also raise the possibility of adults with CTLN2 in whom a diagnosis has yet to be made.

Purpose The aim of this article is to differentiate neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) from biliary atresia (BA) by total hexose. Methods A total of 11 patients with NICCD, 29 patients with BA, and 4,898 children as controls were involved in this study. The blood concentration of amino acids, carnitine, acylcarnitines, and total hexose were measured in dry blood spots (DBS) using tandem mass spectrometry (MS/MS). Results In the patients with NICCD, the blood concentration of the total hexose (15.3 ± 9.0 mmol/L vs. 7.3 ± 2.7 mmol/L; p 0.001), citrulline (Cit) (197.9 ± 93.7 µmol/L vs. 17.5 ± 7.4 µmol/L; p 0.001) were higher than those of patients with BA. Using total hexose (10 mmol/L), Cit (55 µmol/L) to diagnose NICCD, the sensitivity and specificity were 66.7 and 97.8% and 90.0 and 99.1%, respectively, and all of the areas under the receiver-operating characteristic curves were greater than 0.85. Conclusion Elevated total hexose in DBS measured by MS/MS associated with elevated amino acids, especially Cit can be used to diagnose NICCD and differentiate it from BA.

Citrin deficiency is an autosomal recessive genetic disorder caused by a defect in the mitochondrial aspartate/glutamate antiporter, citrin. The disorder manifests either as neonatal intra-hepatic cholestasis or occurs in adulthood with recurrent hyperammonemia and neuropsychiatric disturbances. It has a high prevalence in the East Asian population, but is actually pan-ethnic. We report the case of a 26-year-old male patient presenting with episodes of abnormal neuro-psychiatric behavior associated with hyperammonemia, who was diagnosed to be having citrin deficiency. Sequencing of the SLC25A13 gene revealed two novel mutations, a single base pair deletion, c. 650delT (p.Phe217SerfsFNx0133) in exon 7, and a missense mutation, c. 869T>C (p.Ile290Thr) in exon 9. Confirmation of the diagnosis allowed establishment of the appropriate management. The latter is an essential pre-requisite for obtaining a good prognosis as well as for family counseling.

For this study, we investigated why cholestasis develops into neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and concluded that primary mitochondrial impairment associated with the delayed maturity of bile acid metabolism may contribute to the occurrence of NICCD.

3 páginas, 1 figura, We report citrin deficiency in a neonatal non-East-Asian patient, the ninth Caucasian reported with this disease. The association of intrahepatic cholestasis, galactosuria, very high alpha-fetoprotein and increased plasma and urine citrulline, tyrosine, methionine and threonine levels suggested citrin deficiency. Identification of a protein-truncating mutation (c.1078C>T; p.Arg360*) in the SLC25A13 gene confirmed the diagnosis. An immediate response to a high-protein, lactose-free, low-carbohydrate formula was observed. Our report illustrates the need for awareness on citrin deficiency in Western countries., This work was supported in part by grants BFU2011-30407 and Prometeo 2009/051 of the Spanish and Valencian Governments

Deficiency of citrin encoded by SLC25A13 causes adult-onset type II citrullinemia (CTLN2) and idiopathic neonatal hepatitis (NICCD). So far we have diagnosed 126 (3) CTLN2 and 103 (4) NICCD patients in Japan (and other countries). From preliminary population analysis of the known nine SLC25A13 mutations, we found that the carrier frequency is high in China (1/79), Taiwan (1/98), and Korea (1/50) as well as Japan (1/69), suggesting that many patients with citrin deficiency exist in East Asia.

Citrullinemia is the earliest identifiable biochemical abnormality in neonates with intrahepatic cholestasis due to a citrin deficiency (NICCD) and it has been included in newborn screening panels using tandem mass spectrometry. However, only one neonate was positive among 600,000 infants born in Sapporo city and Hokkaido, Japan between 2006 and 2017. We investigated 12 neonates with NICCD who were initially considered normal in newborn mass screening (NBS) by tandem mass spectrometry, but were later diagnosed with NICCD by DNA tests. Using their initial NBS data, we examined citrulline concentrations and ratios of citrulline to total amino acids. Although their citrulline values exceeded the mean of the normal neonates and 80% of them surpassed +3 SD (standard deviation), all were below the cutoff of 40 nmol/mL. The ratios of citrulline to total amino acids significantly elevated in patients with NICCD compared to the control. By evaluating two indicators simultaneously, we could select about 80% of patients with missed NICCD. Introducing an estimated index comprising citrulline values and citrulline to total amino acid ratios could assure NICCD detection by NBS.

Inborn errors of metabolism (IEMs) are a group of genetic diseases that have protean clinical manifestations and can involve several organ systems. The age of onset is highly variable but IEMs afflict mostly the pediatric population. However, in the past decades, the advancement in management and new therapeutic approaches have led to the improvement in IEM patient care. As a result, many patients with IEMs are surviving into adulthood and developing their own set of complications. In addition, some IEMs will present in adulthood. It is important for internists to have the knowledge and be familiar with these conditions because it is predicted that more and more adult patients with IEMs will need continuity of care in the near future. The review will focus on Wilson disease, alpha-1 antitrypsin deficiency, citrin deficiency, and HFE-associated hemochromatosis which are typically found in the adult population. Clinical manifestations and pathophysiology, particularly those that relate to hepatic disease as well as diagnosis and management will be discussed in detail.

Background: Citrin, encoded by SLC25A13, is a component of the malate-aspartate shuttle, which is the main NADH-transporting system in the liver. Citrin deficiency causes neonatal intrahepatic cholestasis (NICCD), which usually resolves within the first year of life. However, small numbers of adults with citrin deficiency develop hyperammonemic encephalopathy, adult-onset type II citrullinemia (CTLN2), which leads to death due to cerebral edema. Liver transplantation is the only definitive therapy for patients with CTLN2. We previously reported that a lactose (galactose)-restricted and medium-chain triglyceride (MCT)-supplemented formula is notably effective for patients with NICCD. Citrin deficiency may impair the glycolysis in hepatocytes because of an increase in the cytosolic NADH/NAD+ ratio, leading to an energy shortage. MCT administration can provide energy to hepatocytes and was expected to have a good effect on CTLN2. Methods: An MCT supplementation therapy under a low-carbohydrate formula was administered to five patients with CTLN2. Four of the patients had episodes of hyperammonemic encephalopathy, and one patient had postprandial hyperammonemia with no symptoms. Results: One of the patients displaying hyperammonemic encephalopathy completely recovered with all normal laboratory findings. Others notably improved in terms of clinical and or laboratory findings with no hyperammonemic symptoms; however, the patients displayed persistent mild citrullinemia and occasionally had postprandial mild hyperammonemia most likely due to an irreversible change in the liver. Conclusions: An MCT supplement can provide energy to hepatocytes and promote hepatic lipogenesis, leading to a reduction in the cytosolic NADH/NAD+ ratio. MCT supplementation under a low-carbohydrate formula could be a promising therapy for CTLN2 and should also be used to prevent CTLN2 to avoid irreversible liver damage.

Seker-Yilmaz B, Kor D, Tumgor G, Ceylaner S, Onenli-Mungan N. p.Val452Ile mutation of the SLC25A13 gene in a Turkish patient with citrin deficiency. Turk J Pediatr 2017; 59: 311-314. Citrin deficiency is an autosomal recessive metabolic disorder, which is caused by pathogenic mutations in the SLC25A13 gene on chromosome 7q21.3, as the causative gene that encodes the liver type aspartate/glutamate carrier isoform 2 (AGC2). One of the main clinical presentations is neonatal intrahepatic cholestatic hepatitis caused by citrin deficiency. We report a Turkish child presented with prolonged neonatal jaundice associated with elevated plasma citrulline and galactosuria. NICCD was suspected at this point and mutation study of SLC25A13 showed that she was homozygous for the missense NM_014251.2:c.1354G > A (NP_055066.1:p.Val452Ile) (dbSNP: rs143877538) mutation. Dramatic response was observed to the dietary treatment with medium-chain triglycerides containing formula, ursodeoxycholic acid and fat-soluble vitamin supplementation. The minor allele frequency of this variant was given as nearly as 0.01 in the South Asian population; it seems like a disease causing variant. This is the first report of this variant in the Turkish and European population.

Background Tandem mass spectrometry (MS/MS) analysis is a powerful tool for newborn screening, and many rare inborn errors of metabolism are currently screened using MS/MS. However, the sensitivity of MS/MS screening for several inborn errors, including citrin deficiency (screened by citrulline level) and carnitine uptake defect (CUD, screened by free carnitine level), is not satisfactory. This study was conducted to determine whether a second-tier molecular test could improve the sensitivity of citrin deficiency and CUD detection without increasing the false-positive rate. Methods Three mutations in the SLC25A13 gene (for citrin deficiency) and one mutation in the SLC22A5 gene (for CUD) were analyzed in newborns who demonstrated an inconclusive primary screening result (with levels between the screening and diagnostic cutoffs). Results The results revealed that 314 of 46 699 newborns received a second-tier test for citrin deficiency, and two patients were identified; 206 of 30 237 newborns received a second-tier testing for CUD, and one patient was identified. No patients were identified using the diagnostic cutoffs. Although the incidences for citrin deficiency (1:23 350) and CUD (1:30 000) detected by screening are still lower than the incidences calculated from the mutation carrier rates, the second-tier molecular test increases the sensitivity of newborn screening for citrin deficiency and CUD without increasing the false-positive rate. Conclusions Utilizing a molecular second-tier test for citrin deficiency and carnitine transporter deficiency is feasible.