§ Mr. Maclean
To ask the Secretary of State for Health (1) what assessment his Department has made of the alleged linkage of L-tryptophan to Eosinophilia Myalgia Syndrome; 
- (2) how many Eosinophilia Myalgia Syndrome sufferers there are in the UK; and if he will estimate the number who contracted it from L-tryptophan; 
- (3) what information he has collated on genetically modified L-tryptophan. 
§ Ms Jowell
There is no system of mandatory notification in the United Kingdom of cases of Eosinophilia Myalgia Syndrome (EMS) and no central register. Cases of EMS are thought to occur only in association with exposure to L-tryptophan. There were 11 possible cases reported to the Committee on Safety of Medicines by 1991, and there have been 7 possible cases subsequent to the reintroduction of Optimax in 1994, although a causal relationship for these cases has not been established. Several of the cases do not meet the internationally agreed definition of Eosinophilia Myalgia Syndrome. It is not known how many of these patients continue to have symptoms: several of the patients recovered completely after stopping their medicine.
EMS was first recognised as a condition in late-1989. There was extensive investigation into the association between EMS and L-tryptophan by the Medicines Control Agency at that time and the issue was considered in detail by the Committee on Safety of Medicines. It is considered likely that the reported cases of EMS were caused by an impurity or contaminant in L-tryptophan made by a single manufacturer in Japan.
The assessment then and subsequently included review of the worldwide published literature, examination of data submitted by the manufacturers of L-tryptophan and involved liaison with other regulatory authorities in Europe and the USA. In addition, there has been continuing evaluation of individual cases of adverse reactions reported in the United Kingdom under the Yellow Card scheme and via a monitoring scheme operated by the Marketing Authorisation Holder.
L-tryptophan is a simple chemical which cannot be modified genetically. As for all medicines made using biotechnology methods, all the steps taken in the manufacturing process are carefully controlled and have to comply with the specifications stipulated in the marketing authorisation (licence) for the product. All the relevant information is made available by the manufacturers and assessed by the Medicines Control Agency at the time of submission of an application for marketing authorisation and may be subject to ongoing site inspections.