J. Inherit. Metab. Dis. 23 449 È 452 (2000) SSIEM and Kluwer Academic Publishers. Printed in the Netherlands ( Annotation Proceedings of the 4th International Workshop of the Adrenoleukodystrophy International Research Group (ALD-IRG), University of York, 3 September 1998 S. ALGER1*, A. GREEN1, W. KO  HLER2, P. SOKOLOWSKI2 and H. MOSER3 1 Department of Clinical Chemistry, Birmingham ChildrenÏs Hospital, Birmingham, UK; 2 Sachsisches Krankenhaus, Hubertsburg, Department of Neurology, W ermsdorf, Germany ; 3 Neurogenetics, Kennedy Krieger Institute, Baltimore, Maryland, USA * Correspondence : Department of Clinical Chemistry, Birmingham ChildrenÏs Hospital, Steelhouse L ane, Birmingham B4 6NH, UK The question whether LorenzoÏs oil has any beneÐt as a treatment for X-linked adrenoleukodystrophy (ALD, McKusick 300100) is still unanswered. Many centres worldwide are using LorenzoÏs oil but none individually has sufficient patients to produce statistically signiÐcant data to answer the question. For this reason, a small group of professionals (neurologists, biochemists and paediatricians) met at the SSIEM meeting of 1994 in Edinburgh. The objective of the meeting was to share data on boys with biochemically proven ALD who were asymptomatic when treat- ment with LorenzoÏs oil was begun. Eight centres provided information on a total of 100 boys who had been on LorenzoÏs oil for periods of 3 to 78 months (mean 33 months). Side-e†ects reported were thrombocytopenia, lymphocytopenia, raised liver enzymes and reduction of plasma essential fatty acids in some boys. A number of boys deteriorated during therapy. However, the data collected were insufficient for statistical analysis of the outcome of treatment because of the variable natural history of ALD and short length of time for follow-up. The ALD International Research Group (ALD-IRG) was formed to combine retrospective and prospective data over a 5-year period. The primary aims of the group were to study the e†ect of LorenzoÏs oil and diet in asymptomatic patients with ALD and to assess whether the treatment modiÐes the age of onset, rate of progression and eventual outcome of cerebral childhood ALD (CCALD). The inÑu- ence of variables such as age at which treatment started was also studied and pos- sible secondary e†ects of LorenzoÏs oil on blood cells and essential fatty acid levels or changes in growth velocity were monitored. In addition, data collected on 449