Recurrent acute liver failure and mitochondriopathy in a case of Wolcott-Rallison syndrome.

A 10-year-old Arabic boy of consanguineous parents has suffered eight episodes of acute liver failure with haemolysis triggered by intercurrent febrile illnesses. The first crisis occurred at 9 months of age, after which diabetes mellitus developed. By the age of 6 years, short stature, mild myopathy and later skeletal epiphyseal dysplasia also became evident. His psychosocial development and educational achievements have remained within normal limits. While there were no clear biochemical indicators of a mitochondrial disorder, an almost complete deficiency of complex I of the respiratory chain was demonstrated in liver but not in fibroblast or muscle samples. Molecular analysis of the eukaryotic translation initiation factor 2alpha kinase gene (EIF2AK3) demonstrated a homozygous mutation, compatible with a diagnosis of Wolcott-Rallison syndrome (WRS). This patient's course adds a new perspective to the presentation of WRS caused by mutations in the EIF2AK3 gene linking it to mitochondrial disorders: recoverable and recurrent acute liver failure. The findings also illustrate the diagnostic difficulty of mitochondrial disease as it cannot be excluded by muscle or skin biopsy in patients presenting with liver disease. The case also further complicates the decision-making process for liver transplantation in cases of acute liver failure in the context of a possible mitochondrial disorder. Such patients may be more likely to recover spontaneously if a mitochondrial disorder underlies the liver failure, yet without neurological features liver transplantation remains an option.

Indications for pediatric liver transplantation. Data from the Heidelberg pediatric liver transplantation program.

Nowadays liver transplantation is an established treatment for children with end-stage liver disease with very good 1- and 5-year survival. This has been achieved through constant improvement of surgical techniques, new immunosuppressive drugs and clinical management. Indications for liver transplantation in infants and children include acute liver failure (ALF), chronic liver failure with pruritus, complications of cholestasis and failure to thrive. In young children, the most common liver disease leading to transplantation is biliary atresia. Biliary atresia accounts for at least 50 percent of all liver transplants in children and is characterized by the failure of the bile ducts to develop normally and drain bile from the liver. Several models to assess prognosis of liver disease have been developed. In acute liver failure leukocyte count, bilirubin, International Normalized Ratio (INR) and age have a strong correlation with outcome. In chronic liver failure, PELD (Pediatric end-stage liver disease) Score and the occurrence of complications of liver disease are important prognostic tools. Since the start of our own paediatric liver transplantation program at the University of Heidelberg in 2003, already 15 Children between 5 months and 14 years have been transplanted. Indications and outcome of these patients are reviewed in this paper.

Crosstalk between Myc and activating transcription factor 2 (ATF2): Myc prolongs the half-life and induces phosphorylation of ATF2.

Myc is a key regulator of cell growth, differentiation and apoptosis, and affects cell fate decisions by activating as well as by inhibiting the expression of cellular genes. Myc is a member of the basic region-helix-loop-helix-leucine zipper (b-HLH-Zip) class of transcription factors, which heterodimerizes with the Max protein and recognizes a consensus Myc binding motif. Stimulation of gene expression by Myc is thought to be mediated by direct binding of Myc-Max heterodimers to specific target genes. So far, only a few genes have been identified as direct binding targets of Myc, raising the possibility that Myc affects gene expression also by indirect mechanisms. In this work we present evidence that v-Myc encoded by the avian retrovirus MC29 stimulates activating transcription factor 2 (ATF2)-dependent transcription. Analysis of the effect of Myc on ATF2 shows that v-Myc prolongs the half-life of ATF2 and induces the phosphorylation of N-terminal sites of ATF2 (Thr-69 and Thr-71) which have previously been identified as the target sites of stress-activated protein kinases and implicated in the regulation of ATF2 activity. Taken together, our results suggest that v-Myc can affect gene expression indirectly by modulating the activity of ATF2.