The European Union (EU) Council Recommendation on rare diseases urged the member states to implement national and EU collaborative actions to improve the health care of rare disease patients. Following this recommendation, the European Commission launched a tender on newborn screening (NBS) to report on current practices of laboratory testing, form a network of experts and provide guidance on how to further implement NBS screening in a responsible way, the latter of which was provided in an Expert Opinion document. After consultation of experts from EU member states, (potential) candidate member states and European Free Trade Association countries, in a consensus meeting in June 2011, 70 expert opinions were finalized. They included the need to develop case definitions for all disorders screened for to facilitate assessment and international outcome studies. Decision whether a screening program should be performed can be based on screening criteria updated from the traditional Wilson and Jungner (1968) criteria, relating to disease, treatment, test and cost. The interest of the child should be central in the assessment of pros and cons. A European NBS body should assess evidence on (new) screening candidate disorders. For rare conditions, best level evidence should be used. The health system should ensure treatment to cases diagnosed by screening, controlled and revised by follow-up outcome studies. Screening methodology should aim to avoid unintended findings, such as mild forms and carrier status information, as much as possible. Activities to improve NBS in Europe, such as training and scientific evaluation, could benefit from collaboration at EU level and beyond.

The oxidative and reductive cytochrome P450 (P450)-mediated chloroform bioactivation has been investigated in human liver microsomes (HLM), and the role of human P450s have been defined by integrating results from several experimental approaches: cDNA-expressed P450s, selective chemical inhibitors and specific antibodies, correlation studies in a panel of phenotyped HLM. HLM bioactivated CHCl₃ both oxidatively and reductively. Oxidative reaction was characterized by two components, suggesting multiple P450 involvement. The high affinity process was catalyzed by CYP2E1, as clearly indicated by kinetic studies, correlation with chlorzoxazone 6-hydroxylation (r = 0.837; p < 0.001), and inhibition by monoclonal antihuman CYP2E1 and 4-methylpyrazole. The low affinity phase of oxidative metabolism was essentially catalyzed by CYP2A6. This conclusion was supported by the correlation with coumarin 7-hydroxylase (r = 0.777; p < 0.01), inhibition by coumarin and by the specific antibody, in addition to results with heterologously expressed P450s. Chloroform oxidation was poorly dependent on pO₂, whereas the reductive metabolism was highly inhibited by O₂. The production of dichloromethyl radical was significant only at CHCl₃concentration ≥1 mM, increasing linearly with substrate concentration. CYP2E1 was the primary enzyme involved in the reductive reaction, as univocally indicated by all the different approaches. The reductive pathway seems to be scarcely relevant in the human liver, since it is active only at high substrate concentrations, and in strictly anaerobic conditions. The role of human CYP2E1 in CHCl₃ metabolism at low levels, typical of actual human exposure, provides insight into the molecular basis for eventual difference in susceptibility to chloroform-induced effects due to either genetic, pathophysiological, or environmental factors.