Cost-Effectiveness of Primary Liver Transplantation Versus Hepatoportoenterostomy in the Management of Biliary Atresia in the United States.

Biliary atresia (BA) is the leading indication to perform a pediatric liver transplantation (LT). Timely hepatoportoenterostomy (HPE) attempts to interrupt the natural history and allow for enteric bile flow; however, most patients who are treated with HPE require LT by the age of 10 years. We determined the cost-effectiveness of foregoing HPE to perform primary LT (pLT) in children with BA compared with standard-of-care HPE management. A Markov model was developed to simulate BA treatment over 10 years. Costs were measured in 2018 US dollars and effectiveness in life-years (LYs). The primary outcome was incremental cost-effectiveness ratio (ICER) between treatments. Model parameters were derived from the literature. In the base model, we assumed similar LT outcomes after HPE and pLT. Sensitivity analyses on all model parameters were performed, including a scenario in which pLT led to 100% patient and graft survival after LT. Children undergoing HPE accumulated $316,692 in costs and 8.17 LYs per patient. Children undergoing pLT accumulated $458,059 in costs and 8.24 LYs per patient, costing $1,869,164 per LY gained compared with HPE. With parameter variation over plausible ranges, only post-HPE and post-LT costs reduced the ICER below a typical threshold of $100,000 per LY gained. On probabilistic sensitivity analysis, 93% of iterations favored HPE at that threshold. With 100% patient and graft survival after pLT, pLT cost $283,478 per LY gained. HPE is more economically favorable than pLT for BA. pLT is unfavorable even with no graft or patient loss. The ability to predict those patients who may experience high costs after HPE or low costs after LT may help identify those patients for whom pLT could be considered.

Living Related Liver Transplantation for Metabolic Liver Diseases in Children.

ABSTRACT: Metabolic liver diseases (MLDs) are a heterogeneous group of inherited conditions for which liver transplantation can provide definitive treatment. The limited availability of deceased donor organs means some who could benefit from transplant do not have this option. Living related liver transplant (LrLT) using relatives as donors has emerged as one solution to this problem. This technique is established worldwide, especially in Asian countries, with shorter waiting times and patient and graft survival rates equivalent to deceased donor liver transplantation. However, living donors are underutilized for MLDs in many western countries, possibly due to the fear of limited efficacy using heterozygous donors. We have reviewed the published literature and shown that the use of heterozygous donors for liver transplantation is safe for the majority of MLDs with excellent metabolic correction. The use of LrLT should be encouraged to complement deceased donor liver transplantation (DDLT) for treatment of MLDs.

Long-term liver transplant outcomes for progressive familial intrahepatic cholestasis type 1: The Pittsburgh experience.

BACKGROUND: Progressive familial intrahepatic cholestasis type 1 (PFIC1) arises from biallelic variants in the ATP8B1 gene that annul FIC1 activity, resulting in progressive liver disease. Liver transplant (LT) is indicated in refractory disease; however, post-LT complications including worsening diarrhea and steatohepatitis progressing to fibrosis with graft loss have been reported. We aim to describe long-term outcomes of PFIC1 LT recipients at our center, focusing on the histological changes of the allografts. METHODS: We assessed 7 PFIC1 patients post-LT at the Children's Hospital of Pittsburgh (CHP). All pre-transplant, explant, and sequential post-transplant pathology samples were reviewed. Continuous data are presented as the mean ± SD. We compared the pre- and post-transplant height and weight z-scores using Wilcoxon signed-rank test. RESULTS: Seven (29% male) patients with PFIC1 received a LT (n = 6) or had post-LT care (n = 1) at CHP. Six had confirmed or suspected identical genetic. At a mean follow-up of 10.9 years, both patient survival and graft survival were 100%. Diarrhea persisted (n = 3) or newly developed (n = 4) in all patients after LT contributing to ongoing growth failure, with mean z-scores -2.63 (weight) and -2.98 (height) at follow-up. Histologically, allograft steatosis was common but was not accompanied by significant inflammation, ballooning, or fibrosis. CONCLUSION: We show that extrahepatic disease persists and near-universal allograft steatosis occurs. However, at a mean follow-up period of over 10 years, no patients developed steatohepatitis or significant fibrosis, and both patient survival and graft survival are excellent.

Liver transplant for inherited metabolic disease among siblings.

Liver transplantation is a successful option for inherited metabolic disease yet little is published on the outcome among siblings. We report outcomes of siblings who have undergone liver transplantation for metabolic disease in a single program. Seventy-one siblings (35 males) from 33 individual families underwent liver transplantation since 1982. Outcomes were compared over three consecutive eras. Twenty-eight families had two siblings, four had three siblings, and one had four siblings. In half of families where dates of listing were known, siblings were listed simultaneously. Mean (SD) age at listing for the oldest and second sibling was 13.2 (7.1) and 9.8 (5.7) years, respectively (p < .01). In 18/33 families, the oldest sibling underwent transplantation first. Mean (SD) age at transplant fell from the oldest to second sibling from 12.9 (7.2) to 9.5 (6.3) years, respectively (p < .001). Ten-year patient survival was 83.5% which improved over the eras: era 1 (1982-1994) 65.0%, era 2 (1995-2007) 87.5%, and era 3 (2008-2019) 93.8%: p < .03. Sex, age at transplant, order of transplant, and presence of structural liver disease did not significantly impact survival. When siblings undergo liver transplant for inherited metabolic disease, later siblings are listed and transplanted at a significantly younger age.

Successful liver transplantation in short telomere syndromes without bone marrow failure due to DKC1 mutation.

Short telomere syndromes are a heterogenous spectrum of disorders leading to premature cellular aging. These may involve bone marrow failure, adult-onset idiopathic pulmonary fibrosis, and liver disease, and classical entities such as dyskeratosis congenita. We report a patient who presented with common variable immunodeficiency at 3 years of age and autoimmune cytopenias at 8 years of age. He was found to have short telomeres, and genetic testing confirmed a hemizygous mutation NM_001363.4: c.-142C > G in DKC1 gene. He subsequently developed cirrhosis with severe portal hypertension and hepatopulmonary syndrome, prompting liver transplantation at 11 years of age. He remains well 10 years after transplant with no progression of bone marrow failure or progressive lung disease. In conclusion, short telomere syndromes should be considered as a potential cause of pediatric liver disease of unknown etiology, and in severe cases, isolated liver transplantation may be both appropriate and successful.

Evolving Trends in Liver Transplant for Metabolic Liver Disease in the United States.

Indications for liver transplantation (LT) in metabolic disease are evolving. We reviewed the US experience with primary LT for metabolic disease in the Scientific Registry for Transplant Recipients (October 1987 to June 2017) to determine the following: temporal changes in indications, longterm outcomes, and factors predicting survival. Patients were grouped by the presence of structural liver disease (SLD) and whether the defect was confined to the liver. There were 5996 patients who underwent LT for metabolic disease, 2354 (39.3%) being children. LT for metabolic disease increased in children but not in adults. Children experienced a 6-fold increase in LT for metabolic disease without SLD. Indications for LT remained stable in adults. Living donor liver transplantation increased between era 1 and era 3 from 5.6% to 7.6% in children and 0% to 4.5% in adults. Patient and graft survival improved with time. The latest 5-year patient survival rates were 94.5% and 81.5% in children and adults, respectively. Outcomes were worse in adults and in those with extrahepatic disease (P < 0.01), whereas SLD did not affect outcomes. Survival improved with younger age at LT until age <2 years. On multivariate analysis, diagnostic category, inpatient status, age at LT, and transplant era significantly predicted outcomes in all ages with male sex predicting survival in childhood only. Children without structural disease were less likely to die awaiting LT and had improved post-LT survival compared with children with chronic liver disease. In conclusion, LT for metabolic disease is increasingly used for phenotypic correction in children; extrahepatic manifestations significantly impact survival at all ages; where indicated, transplantation should not be unnecessarily delayed; and the development of new allocation models may be required.

Biallelic Mutations in NBAS Cause Recurrent Acute Liver Failure with Onset in Infancy.

Acute liver failure (ALF) in infancy and childhood is a life-threatening emergency. Few conditions are known to cause recurrent acute liver failure (RALF), and in about 50% of cases, the underlying molecular cause remains unresolved. Exome sequencing in five unrelated individuals with fever-dependent RALF revealed biallelic mutations in NBAS. Subsequent Sanger sequencing of NBAS in 15 additional unrelated individuals with RALF or ALF identified compound heterozygous mutations in an additional six individuals from five families. Immunoblot analysis of mutant fibroblasts showed reduced protein levels of NBAS and its proposed interaction partner p31, both involved in retrograde transport between endoplasmic reticulum and Golgi. We recommend NBAS analysis in individuals with acute infantile liver failure, especially if triggered by fever.

Hepatopulmonary Syndrome in Children: A 20-Year Review of Presenting Symptoms, Clinical Progression, and Transplant Outcome.

Hepatopulmonary syndrome (HPS) in stable patients with cirrhosis can easily be overlooked. We report on the presenting symptoms, disease progression, and outcomes after liver transplantation (LT) in children with HPS. Twenty patients were diagnosed with HPS between 1996 and 2016. The etiologies were as follows: biliary atresia (n = 9); alpha-1-antitrypsin deficiency (n = 2); cryptogenic liver disease (n = 3); and others (n = 6). HPS presentations were as follows; dyspnea (n = 17) and pneumonia (n = 3). For diagnostic confirmation, the following techniques were used: technetium-99m-labeled macroaggregated albumin lung perfusion scan (n = 13) or contrast echocardiogram (n = 7). There were 16 patients listed for LT, with a median age at HPS diagnosis of 10 years and an average wait from listing to LT of 9 weeks. A marked rise in hemoglobin (Hb; median, 125-143.5 g/L) and modest decrease in oxygen saturation (SpO2 ; median 91% to 88% room air) were evident over this time. Patients' need for assisted ventilation (1 day), pediatric intensive care unit (PICU) stay (3 days), and total hospital stay (20 days) were similar to our general LT recipients-the key difference in the postoperative period was the duration of supplementary O2 requirement. Hb of ≥130 g/L on the day of LT correlated with a longer PICU stay (P value = 0.02), duration of supplementary O2 (P value = 0.005), and the need for the latter beyond 7 days after LT (P value = 0.01). Fifteen patients had resolution of their HPS after LT. The 5-, 10-, and 20-year survival rates were unchanged at 87.5%. None had a recurrence of HPS. In conclusion, HPS is a life-threatening complication of cirrhosis which usually develops insidiously. This combined with the often-stable nature of the liver disease leads to delays in diagnosis and listing for LT. Progressive polycythemia extends the need for supplementary O2 and PICU stay. We advocate screening for HPS with a combination of SpO2 and Hb monitoring to facilitate earlier recognition, timely LT, and shortened recovery periods.

Survival of children after liver transplantation for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) in childhood differs from adult HCC because it is often associated with inherited liver disease. It is, however, unclear whether liver transplantation (LT) for HCC in childhood with or without associated inherited disease has a comparable outcome to adult HCC. On the basis of data from the European Liver Transplant Registry (ELTR), we aimed to investigate if there are differences in patient and graft survival after LT for HCC between children and adults and between patients with underlying inherited versus noninherited liver disease, respectively. We included all 175 children who underwent LT for HCC and were enrolled in ELTR between 1985 and 2012. Of these, 38 had an associated inherited liver disease. Adult HCC patients with (n = 79) and without (n = 316, matched by age, sex, and LT date) inherited liver disease served as an adult comparison population. We used multivariable piecewise Cox regression models with shared frailty terms (for LT center) to compare patient and graft survival between the different HCC groups. Survival analyses demonstrated a superior longterm survival of children with inherited liver disease when compared with children with HCC without inherited liver disease (hazard ratio [HR], 0.29; 95% CI, 0.10-0.90; P = 0.03) and adults with HCC with inherited liver disease (HR, 0.27; 95% CI, 0.06-1.25; P = 0.09). There was no survival difference between adults with and without inherited disease (HR, 1.05; 95% CI, 0.66-1.66; P = 0.84). In conclusion, the potential survival advantage of children with an HCC based on inherited disease should be acknowledged when considering transplantation and prioritization for these patients. Further prospective studies accounting for tumor size and extension at LT are necessary to fully interpret our findings. Liver Transplantation 24 246-255 2018 AASLD.

Daily variation of NTBC and its relation to succinylacetone in tyrosinemia type 1 patients comparing a single dose to two doses a day.

INTRODUCTION: In hereditary tyrosinemia type 1 (HT1) patients, the dose of NTBC that leads to the absence of toxic metabolites such as succinylacetone (SA) is still unknown. Therefore, the aims of this study were to investigate the variation and concentrations of 2-(2-nitro-4-trifluormethyl-benzyl)-1,3-cyclohexanedione (NTBC) during the day in relation to the detection of SA, while comparing different dosing regimens. METHODS: All patients were treated with NTBC (mean 1.08 ± 0.34 mg/kg/day) and a low phenylalanine-tyrosine diet. Thirteen patients received a single dose of NTBC and five patients twice daily. Home bloodspots were collected four times daily for three consecutive days measuring NTBC and SA concentrations. Statistical analyses were performed by using mixed model analyses and generalized linear mixed model analyses to study variation and differences in NTBC concentrations and the correlation with SA, respectively. RESULTS: NTBC concentrations varied significantly during the day especially if NTBC was taken at breakfast only (p = 0.026), although no significant difference in NTBC concentrations between different dosing regimens could be found (p = 0.289). Momentary NTBC concentrations were negatively correlated with SA (p < 0.001). Quantitatively detectable SA was only found in subjects with once daily administration of NTBC and associated with momentary NTBC concentrations <44.3 µmol/l. DISCUSSION: NTBC could be less stable than previously considered, thus dosing NTBC once daily and lower concentrations may be less adequate. Further research including more data is necessary to establish the optimal dosing of NTBC.

Transjugular Intrahepatic Portosystemic Shunt Insertion for the Management of Portal Hypertension in Children.

OBJECTIVES: the aim of the study was to describe our 20-year experience with transjugular intrahepatic portosystemic shunt (TIPSS) procedures for children with resistant portal hypertension (PHTN). METHODS: Retrospective review of all children that had a TIPSS performed at Birmingham Children's Hospital from January 1, 1995 to January 1, 2015. RESULTS: Forty children underwent 42 attempted TIPSS for resistant PHTN with recurrent variceal bleeding (n = 35), refractory ascites (n = 4), and hypersplenism (n = 1). Median age at operation was 12 years (range 7 months-17 years). Thirty-four procedures were elective and 8 were emergency cases. TIPSS was established in 33 cases (79%). Median portal venous pressure reduction was 10 mmHg. Variceal bleeding ceased in 27 (96%) and ascites improved in all. Clinical improvement following TIPSS enabled 7 children to be bridged to transplantation and 7 others to become suitable for transplantation. The 1-year and 5-year survival with TIPSS was 57% and 35%, respectively. Child-Pugh score C was an independent risk factor for adverse outcome (Likelihood ratio (LR) = 8.0; 95% confidence interval (CI) 2.7 to 23.5; P = 0.001). There were 6 major complications: hepatic artery thrombosis and infarction (n = 1), hepatic artery pseudoaneurysm (n = 1), bile leak (n = 1), and hepatic encephalopathy (n = 3). Encephalopathy was resistant to medical treatment in 2 cases, necessitating staged closure in 1. Ten patients (30%) required intervention to maintain TIPSS patency. The 1-year and 5-year freedom from reintervention was 71% and 55%, respectively. CONCLUSIONS: A TIPSS is highly successful in controlling symptoms in children with resistant PHTN and facilitating liver transplantation. It is technically demanding and not without risk. Patients must be appropriately selected and counselled.

UK guideline on transition of adolescent and young persons with chronic digestive diseases from paediatric to adult care.

The risks of poor transition include delayed and inappropriate transfer that can result in disengagement with healthcare. Structured transition care can improve control of chronic digestive diseases and long-term health-related outcomes. These are the first nationally developed guidelines on the transition of adolescent and young persons (AYP) with chronic digestive diseases from paediatric to adult care. They were commissioned by the Clinical Services and Standards Committee of the British Society of Gastroenterology under the auspices of the Adolescent and Young Persons (A&YP) Section. Electronic searches for English-language articles were performed with keywords relating to digestive system diseases and transition to adult care in the Medline (via Ovid), PsycInfo (via Ovid), Web of Science and CINAHL databases for studies published from 1980 to September 2014. The quality of evidence and grading of recommendations was appraised using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. The limited number of studies in gastroenterology and hepatology required the addition of relevant studies from other chronic diseases to be included.These guidelines deal specifically with the transition of AYP living with a diagnosis of chronic digestive disease and/or liver disease from paediatric to adult healthcare under the following headings;1. Patient populations involved in AYP transition2. Risks of failing transition or poor transition3. Models of AYP transition4. Patient and carer/parent perspective in AYP transition5. Surgical perspective.

Glycogen storage disease type III: diagnosis, genotype, management, clinical course and outcome.

Glycogen storage disease type III (GSDIII) is a rare disorder of glycogenolysis due to AGL gene mutations, causing glycogen debranching enzyme deficiency and storage of limited dextrin. Patients with GSDIIIa show involvement of liver and cardiac/skeletal muscle, whereas GSDIIIb patients display only liver symptoms and signs. The International Study on Glycogen Storage Disease (ISGSDIII) is a descriptive retrospective, international, multi-centre cohort study of diagnosis, genotype, management, clinical course and outcome of 175 patients from 147 families (86 % GSDIIIa; 14 % GSDIIIb), with follow-up into adulthood in 91 patients. In total 58 AGL mutations (non-missense mutations were overrepresented and 21 novel mutations were observed) were identified in 76 families. GSDIII patients first presented before the age of 1.5 years, hepatomegaly was the most common presenting clinical sign. Dietary management was very diverse and included frequent meals, uncooked cornstarch and continuous gastric drip feeding. Chronic complications involved the liver (hepatic cirrhosis, adenoma(s), and/or hepatocellular carcinoma in 11 %), heart (cardiac involvement and cardiomyopathy, in 58 % and 15 %, respectively, generally presenting in early childhood), and muscle (pain in 34 %). Type 2 diabetes mellitus was diagnosed in eight out of 91 adult patients (9 %). In adult patients no significant correlation was detected between (non-) missense AGL genotypes and hepatic, cardiac or muscular complications. This study demonstrates heterogeneity in a large cohort of ageing GSDIII patients. An international GSD patient registry is warranted to prospectively define the clinical course, heterogeneity and the effect of different dietary interventions in patients with GSDIII.

Recurrent acute liver failure due to NBAS deficiency: phenotypic spectrum, disease mechanisms, and therapeutic concepts.

BACKGROUND: Acute liver failure (ALF) in infancy and childhood is a life-threatening emergency and in about 50% the etiology remains unknown. Recently biallelic mutations in NBAS were identified as a new molecular cause of ALF with onset in infancy, leading to recurrent acute liver failure (RALF). METHODS: The phenotype and medical history of 14 individuals with NBAS deficiency was studied in detail and functional studies were performed on patients' fibroblasts. RESULTS: The phenotypic spectrum of NBAS deficiency ranges from isolated RALF to a multisystemic disease with short stature, skeletal dysplasia, immunological abnormalities, optic atrophy, and normal motor and cognitive development resembling SOPH syndrome. Liver crises are triggered by febrile infections; they become less frequent with age but are not restricted to childhood. Complete recovery is typical, but ALF crises can be fatal. Antipyretic therapy and induction of anabolism including glucose and parenteral lipids effectively ameliorates the course of liver crises. Patients' fibroblasts showed an increased sensitivity to high temperature at protein and functional level and a disturbed tethering of vesicles, pointing at a defect of intracellular transport between the endoplasmic reticulum and Golgi. CONCLUSIONS: Mutations in NBAS cause a complex disease with a wide clinical spectrum ranging from isolated RALF to a multisystemic phenotype. Thermal susceptibility of the syntaxin 18 complex is the basis of fever dependency of ALF episodes. NBAS deficiency is the first disease related to a primary defect of retrograde transport. Identification of NBAS deficiency allows optimized therapy of liver crises and even prevention of further episodes.

Interobserver Agreement on Endoscopic Classification of Oesophageal Varices in Children.

OBJECTIVES: Data regarding agreement on endoscopic features of oesophageal varices in children with portal hypertension (PH) are scant. The aim of this study was to evaluate endoscopic visualisation and classification of oesophageal varices in children by several European clinicians, to build a rational basis for future multicentre trials. METHODS: Endoscopic pictures of the distal oesophagus of 100 children with a clinical diagnosis of PH were distributed to 10 endoscopists. Observers were requested to classify variceal size according to a 3-degree scale (small, medium, and large, class A), a 2-degree scale (small and large, class B), and to recognise red wales (presence or absence, class Red). Overall agreement was considered fair if Fleiss and Cohen κ test was ≥0.30, good if ≥0.40, excellent if ≥0.60, and perfect if ≥0.80. RESULTS: Agreement between observers was fair with class A (κ = 0.34) and class B (κ = 0.38), and good with class Red (κ = 0.49). The agreement was good on presence versus absence of varices (class A = 0.53, class B = 0.48). The agreement among the observers was good in class A when endoscopic features of severe PH (medium and large sizes, red marks) were grouped and compared with mild features (absent and small varices) (κ = 0.58). CONCLUSIONS: Experts working in different centres show a fairly good agreement on endoscopic features of PH in children, although a better training of paediatric endoscopists may improve the agreement in grading severity of varices in this setting.

Early nitisinone treatment reduces the need for liver transplantation in children with tyrosinaemia type 1 and improves post-transplant renal function.

BACKGROUND: Tyrosinaemia type 1 (HT1) is a rare disorder of tyrosine metabolism leading to liver failure and hepatocellular carcinoma. Treatment previously consisted of dietary restriction and orthotopic liver transplantation (OLT) but was transformed by the introduction of nitisinone in 1992. We describe the impact of nitisinone on the outcome and need for OLT in a single centre. METHODS: A retrospective analysis was performed of patients treated for HT1 at Birmingham Children's Hospital from 1989-2009. RESULTS: Thirty eight patients were treated during the study period. Prior to 1992 6/7 (85.7 %) underwent OLT compared to 7/31 (22.6 %) after 1992 (p = 0.004) when nitisinone treatment was available. Furthermore, nitisinone-treated patients proceeding to OLT started treatment at a median age of 428 (86-821) days compared to 52 (2-990) days in those who did not (p = 0.004). Pre-OLT calculated glomerular filtration rate (cGFR) was similar in both groups but nitisinone prevented early decline after OLT (pre-nitisinone median 99.8 to 45.8 ml/min/1.73 m2, p = 0.02 versus nitisinone-treated group median 104.3 to 89.9 ml/min/1.73 m2, p = 0.5). Urinary protein:creatinine ratio (PCR) fell post-OLT to within the normal range for those treated with nitisinone but remained elevated in those not treated with nitisinone. Tubular reabsorption of phosphate (TRP) was normal or near normal in both groups pre-OLT and post-OLT. Hypertension was commoner and more severe in those not treated with nitisinone. CONCLUSIONS: Nitisinone reduces the need for OLT particularly when started early. For those progressing to OLT the use of prior nitisinone therapy results in a preservation of their subsequent renal function.

Population pharmacokinetic and pharmacogenetic analysis of tacrolimus in paediatric liver transplant patients.

AIMS: To build a population pharmacokinetic model that describes the apparent clearance of tacrolimus and the potential demographic, clinical and genetically controlled factors that could lead to inter-patient pharmacokinetic variability within children following liver transplantation. METHODS: The present study retrospectively examined tacrolimus whole blood pre-dose concentrations (n = 628) of 43 children during their first year post-liver transplantation. Population pharmacokinetic analysis was performed using the non-linear mixed effects modelling program (nonmem) to determine the population mean parameter estimate of clearance and influential covariates. RESULTS: The final model identified time post-transplantation and CYP3A5*1 allele as influential covariates on tacrolimus apparent clearance according to the following equation: TVCL = 12.9 x (Weight/13.2)(0.75) x EXP(-0.00158 x TPT) x EXP(0.428 x CYP3A5) where TVCL is the typical value for apparent clearance, TPT is time post-transplantation in days and the CYP3A5 is 1 where *1 allele is present and 0 otherwise. The population estimate and inter-individual variability (%CV) of tacrolimus apparent clearance were found to be 0.977 l h(-1) kg(-1) (95% CI 0.958, 0.996) and 40.0%, respectively, while the residual variability between the observed and predicted concentrations was 35.4%. CONCLUSION: Tacrolimus apparent clearance was influenced by time post-transplantation and CYP3A5 genotypes. The results of this study, once confirmed by a large scale prospective study, can be used in conjunction with therapeutic drug monitoring to recommend tacrolimus dose adjustments that take into account not only body weight but also genetic and time-related changes in tacrolimus clearance.

Plasma succinylacetone is persistently raised after liver transplantation in tyrosinaemia type 1.

BACKGROUND: Tyrosinaemia type 1 (HT1) is a rare disorder leading to accumulation of toxic metabolites such as succinylacetone (SA) and a high risk of hepatocellular carcinoma. Children with HT1 traditionally required liver transplantation (OLT) and while the need for this has been reduced by the introduction of nitisinone some still require OLT. SA inhibits the enzyme porphobilinogen (PBG) synthase and its activity can be used as a marker of active SA. Elevated urinary SA post OLT has been reported previously. This study describes a novel finding of elevated plasma SA following OLT for HT1. METHODS: A retrospective analysis was performed of patients treated for HT1 at our institution from 1989-2010. RESULTS: Thirteen patients had an OLT for HT1. In patients who received nitisinone prior to OLT, mean urinary and plasma SA were elevated prior to treatment but normalised by the time of OLT (p ≤ 0.01). Mean PBG synthase activity increased from 0.032 to 0.99 nkat/gHb (ref range 0.58-1.25) at the time of OLT (p < 0.01). Mean urinary SA in patients not treated with nitisinone was also elevated prior to OLT; plasma levels and PBG synthase activity were not available prior to OLT for this group. Following OLT, mean urinary and plasma SA were elevated in all for the duration of follow-up and associated with low-normal PBG synthase activity. CONCLUSION: Urinary and plasma SA levels are elevated following OLT for HT1. Low-normal PBG synthase activity suggests the plasma SA may be active. The clinical significance of this is unclear.