Diagnosis of inborn errors of metabolism

Systematic detection of inborn errors of metabolism (IEM) has usually encou ntered difficulties in developing countries. We present our experience in a high-risk population in Mexico between 1973 and 1998 with particular refer ence to the last 10 years, during which time infrastructure and support wer e considerably improved. Only disorders of intermediary metabolism were sou ght. The total number of patients studied is not available, but in the last 10 years, patients numbered 5,186. Routine metabolic screening was per for med on all patients, with additional tests according to the clinical pictur e and screening results. The referral criteria have increasingly diversifie d, one-third being neurological conditions. Of the referrals, 33.8% were fr om pediatricians (31.1% of whom were at critical medicine departments) and the remainder from specialists. The number of diagnosed patients has increa sed to 1 per 43.9 patients studied. Amino acid defects have been the most p revalent, the proportion of organic acid and carbohydrate disorders having increased in the last 10 years, associated with improved diagnostic facilit ies. The most frequently diagnosed diseases were PKU, type la glycogen stor age, and maple syrup urine disease (MSUD), their frequency apparently varyi ng among different regions of Mexico. Other results of our program include training of specialists and technicians, development of the Latin American Metabolic Information Network, a procedure to locally prepare a special foo d product low in phenylalanine for the treatment of PKU patients, and exten sion of approaches for these disorders to the investigation metabolic deran gements of infant malnutrition. This work demonstrates that inherited metab olic diseases constitute a significant load in pediatric pathology and that their study can and should be pursued in developing nations. (C) 2000 IMSS . Published by Elsevier Science Inc.