New variants in Spanish Niemann-Pick type c disease patients.

Niemann-Pick type C (NPC) disease is a rare inherited disease, with progressive neurodegeneration as the main symptom. It is a lysosomal storage disorder caused by mutations in NPC1 or NPC2 genes, leading to a lysosomal cholesterol trafficking impairment. Disease indicators are the clinical suspicion and biomarker levels. However, a genetic study is mandatory for the diagnosis, which is complicated due to the different variants with unknown significance. The aim of this work was to identify the variants responsible for NPC in our pediatric population. Twenty-two samples from non-related infants believed to have NPC disease were analyzed during the last 3 years. Surrogate biomarkers of the disease were evaluated whenever possible. Sanger sequencing for both genes is reported for all samples. Complementary genetic studies were performed when necessary. NPC disease was confirmed in 31.8% of subjects due to homozygous or compound heterozygous genetic variants in NPC1. The following four novel variants were identified: a gross deletion variant composed of the gene promoter and the first exon, NM_000271.3:c.385delT, NM_000271.3:c.1553+1342_1655-291del, and NM_000271.3:c.1757delA. None had functional activity and all resulted in important structural changes in the protein.

Liver transplantation for classical maple syrup urine disease: long-term follow-up.

OBJECTIVES: The aim of the study was to evaluate indications, results, and clinical and neurological evolution in children who have undergone liver transplantation for classical maple syrup urine disease (MSUD). METHODS: Descriptive study of liver transplantation for MSUD between 1991 and 2012. Eight patients were transplanted. RESULTS: Indications for transplant were poor metabolic control expressed as significant psychomotor disabilities (4 had psychomotor delays, 5 had spasticity, and 5 had epilepsy) and poor quality of life (mean number of acute metabolic decompensations and mean number of total hospitalizations before transplantation 5 and 12, respectively). Four required nasogastric tube, with a maximum 4 g/day protein-restricted diet in all of them. Seven sustained significant alterations in brain magnetic resonance imaging. Mean leucine and alloisoleucine levels were 608 (standard deviation [SD] 516) and 218 µmol/L (SD 216), respectively. All of the patients received transplants with deceased-donor livers, with ages between 1.5 and 2.5 years (mean 1.78 years). Mean posttransplantation follow-up period was 12.2 years (range 5-21 years). Final patient and graft survival was 87.5% and 75%, respectively. Following transplantation, none required hospitalization in the last 3 years nor did any have new acute metabolic decompensations following a normal diet. Five followed normal schooling, 2 had motor disabilities, and 2 had convulsive crises. Brain magnetic resonance imaging was taken in 4 patients, showing neuroimage improvement in 3 of them. Mean leucine levels were <350 µmol/L from the immediate posttransplantation period (mean 225 µmol/L, SD 78), with a maximum alloisoleucine level of 20 µmol/L. CONCLUSIONS: Liver transplantation is an effective treatment for classical MSUD that arrests brain damage, although it does not reverse the process.

Recurrence of bile salt export pump deficiency after liver transplantation.

Severe bile salt export pump (BSEP) deficiency is a hereditary cholestatic condition that starts in infancy and leads to end-stage liver disease. Three children who underwent orthotopic liver transplantation for severe BSEP deficiency had post-transplantation episodes of cholestatic dysfunction that mimicked the original disease. Remission of all episodes was achieved by intensifying the immunosuppressive regimen. The phenotypic recurrence of the disease correlated with the presence of circulating high-titer antibodies against BSEP that inhibit transport by BSEP in vitro. When administered to rats, these antibodies targeted the bile canaliculi and impaired bile acid secretion.

Efficacy and safety of valganciclovir in liver-transplanted children infected with Epstein-Barr virus.

Epstein-Barr virus (EBV) infection after liver transplantation (LT) is associated with increased risk of posttransplant lymphoproliferative disorder (PTLD). Lowering immunosuppression is the current method to prevent PTLD in LT children with a high viral load. The aim of this study was to assess the efficacy and safety of valganciclovir (VGCV) in children with EBV infection after LT. Forty-seven children showing detectable EBV-DNA (72% asymptomatic) were treated with VGCV (520 mg/sqm twice daily) with no immunosuppression decrease (except in 4 cases). VGCV treatment started 17 months (median) after the onset of EBV infection. A 30-day treatment applied to 26 patients led to undetectable EBV-DNA in 11/32 courses (34.3%), with 82% relapsing. A long VGCV treatment (median: 8 months) achieved undetectable EBV-DNA in 20/42 (47.6%), 60% of whom maintained response off therapy. There were no new PTLD cases. Symptoms worsened in 1 (2.1%) in whom PTLD was suspected but not confirmed in liver and jejunum biopsies. Factors associated with achievement of undetectable EBV-DNA were a longer time from LT and a lower rate of intervening infections in comparison with nonresponders. The safety profile for VGCV was excellent. Graft rejection occurred in 6%. In conclusion, in 47 LT children with a sustained increased EBV load treated with VGCV and unchanged immunosuppression, PTLD was suspected in 1 child (2.1%). A viral load decrease could be achieved as EBV-DNA was undetectable in 47% of patients under prolonged treatment.

Efficacy and safety of peginterferon-alpha2b and ribavirin combination therapy in children with chronic hepatitis C infection.

BACKGROUND: Interferon (IFN)-alpha2b plus ribavirin is approved for treatment of hepatitis C in children; however, little is known about efficacy and tolerability of pegylated IFN (PEG-IFN)-alpha2b in this population. The objective of this study was to test the efficacy and safety of PEG-IFN-alpha2b plus ribavirin in children with chronic hepatitis C. METHODS: Thirty children 3-16 years of age who had detectable hepatitis C virus (HCV) RNA for >or=3 years after exposure and elevated alanine aminotransferase values received PEG-IFN-alpha2b 1.0 microg/kg/wk plus ribavirin 15 mg/kg/d for 24 weeks (genotype 2/3) or 48 weeks (genotype 1/4). The primary endpoint was sustained virologic response (SVR), defined as undetectable HCV RNA (<50 IU/mL) at week 24 of follow-up. RESULTS: SVR was achieved in 50% of patients (3/3 genotype 3; 12/27 genotype 1/4). At week 12, 52% of patients were HCV RNA negative and 72% had a >2 log10 decrease in viral load, compared with baseline; 87% and 71% of these patients, respectively, attained an SVR. Therapy was discontinued in 3 patients as a result of adverse events. No patient required ribavirin dose reduction; PEG-IFN-alpha2b dose was reduced in 23% of patients to manage neutropenia. CONCLUSIONS: Combination therapy with PEG-IFN-alpha2b and ribavirin treatment was effective in children with chronic hepatitis C. Virologic status at week 12 identified future responders and nonresponders. PEG-IFN-alpha2b and ribavirin were reasonably well tolerated, with no unexpected or permanent adverse effects. Further studies are needed to identify the optimum treatment regimen for this patient population.

Reduced hepatic expression of farnesoid X receptor in hereditary cholestasis associated to mutation in ATP8B1.

Farnesoid X receptor (FXR) is a transcription factor that controls bile acid homeostasis. The phenotype of Fxr null mice is characterized by hypercholanaemia, impaired secretion of bile acids and failure to thrive. Human disorders with these characteristics include FIC1 disease (caused by mutations in ATP8B1, which encodes a putative aminophospholipid translocase, FIC1, whose function in bile handling is unknown) and bile salt export pump (BSEP) disease (caused by mutation in ABCB11, which encodes BSEP, the primary canalicular bile salt export pump). We investigated the possibility of hepatic down-regulation of FXR in FIC1 disease and BSEP disease. Three siblings with this phenotype, born to consanguine parents, were initially studied. The children were demonstrated to be compound heterozygotes for missense and nonsense mutations in ATP8B1. Expression of specific genes in liver was analysed, comparing one of these siblings with a child homozygous for missense mutation in ABCB11, as well as with a child having idiopathic cholestatic liver disease, a child with extrahepatic biliary atresia and a normal organ donor. The expression of two main FXR isoforms was specifically decreased in the liver of the FIC1 disease patient. A consistent and concomitant reduction in messenger RNA levels of FXR targets, such as BSEP and small heterodimer partner, was also found. Gene-profiling experiments identified 163 transcripts whose expression changed significantly in FIC1-disease liver. Of note was that several genes involved in synthesis, conjugation and transport of bile acids were down-regulated. A cluster of genes involved in lipid metabolism was also differentially expressed. Our findings suggest that hepatic down-regulation of FXR contributes to the severe cholestasis of FIC1 disease.