Epidermal integrity is essential for skin functions. It is maintained by adhesive structures between keratinocytes, mainly the desmosomes and adherens junctions, which provide resistance against mechanical stress and regulate the formation of the skin barrier. As a constituent of both types of intercellular junctions, plakoglobin has multiple interaction partners and mutations in its gene [junction plakoglobin (JUP)] have been associated with mild cutaneous disease, palmoplantar keratoderma and arrhythmogenic heart disease. Here we report a novel lethal phenotype caused by a homozygous nonsense JUP mutation, c.1615C>T, p.Q539X, which is very different from any human or murine JUP phenotype described so far. The patient suffered from severe congenital skin fragility with generalized epidermolysis and massive transcutaneous fluid loss, but apparently no cardiac dysfunction. In contrast to previously reported JUP mutations where truncated proteins were still present, in this case there was complete loss of plakoglobin in the patient's skin, as demonstrated by immunofluorescence and immunoblot analysis. As a consequence, only very few abnormal desmosomes were formed and no adhesion structures between keratinocytes were recognizable. The expression and distribution of desmosomal components was severely affected, suggesting an essential role for plakoglobin in desmosomal assembly. Adherens junction proteins were localized to keratinocyte plasma membrane, but did not provide proper cell-cell adhesion. This lethal congenital epidermolysis bullosa highlights the fundamental role of plakoglobin in epidermal cohesion.

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Pharmacokinetics after high-dose (HD) etoposide (Eto) (40 mg/kg i.v. once as 4-h infusion, one patient 20 mg/kg i.v. as 4-h infusion, for 3 consecutive days) were studied in 31 children and young adults (age 0.8-23.7 years, median: 8.0 years) undergoing bone marrow transplantation after different conditioning regimens. Blood samples were collected until 97 h after the end of infusion. The population analysis of the first part of data (112 samples/21 patients, well documented) served to establish the pharmacokinetic model. The same data combined with the second part of data (50 samples/10 patients, 'intention to treat') then served to calculate the final population model. Data were best described by a three-compartment model with t1/2alpha = 0.28 h +/- 3.2%, t1/2beta = 3.6 h +/- 16.9% and t1/2gamma = 44.2 h +/- 56.5%, respectively (mean(geom) +/- CV(geom)). Clearance (CL) was 15.5 ml/min/m2 +/- 30.6% (mean(geom) +/- CV(geom)) and thus at the lower range of data reported in the literature. The fraction of unbound Eto (fu) was 7.0% (4.3-11.9%) [median (range)], with high intra-individual variability. An increase in f(u) with increasing total Eto was observed. The question of a principally lower Eto CL in children, as compared to adults, after HD treatment remains open.

Limited data exist on therapeutic options for established hepatic veno-occlusive disease (VOD) in pediatric patients after stem cell transplantation (SCT). In this report, we present data on the successful treatment of VOD in three children following allogeneic SCT and report the duplex ultrasound criteria for the confirmation of the diagnosis and for the evaluation of the treatment progress. All patients were <2 years at the time of transplantation and had received preparative regimens containing busulfan and cyclophosphamide. There were no known pretransplant risk factors for VOD. Allogeneic stem cell transplantation was performed from a sibling donor for CMML and from unrelated donors for Wiskott-Aldrich syndrome and familial hemophagocytic lymphohistiocytosis (FHL). The onset of first clinical symptoms of VOD (as defined by the Seattle and Baltimore criteria) was relatively late in all three patients (days +19, +20, and +25, respectively). Time from onset of first symptoms until confirmation of diagnosis by serial duplex ultrasound examination was 4-11 days. Duplex ultrasound criteria are as follows: complete change of direction of blood flow in the portal vein, decrease of flow in the hepatic veins, and development of collateral circulation. Treatment was initiated upon confirmation of VOD by continuous infusion of prostaglandin E1 (initial dose 0.075 microg/kg/h) in addition to low-dose heparin (100 units/kg/d). Treatment was continued at the maximum tolerated dose of 0.3-0.5 microg/kg/h of PGE1. After 9, 14, and 25 days of treatment respectively, normal portal vein flow was restored and treatment could be discontinued. All three patients are alive and well without apparent sequelae.

In the case of etoposide, special dose-calculation guidelines for infants are not substantiated by age-dependent pharmacokinetics or tolerance.