PIP: Dr. Holger Hansen comments on an article by Buist and Jhavarie on maternal hyperphenylalaninemia. The noted that the condition causes prenatal brain damage and recommended a low-phenylalanine diet during pregnancy for women with blood phyenylalanine levels greater than 10 to 15 mg per 100 ml. In the same Journal of Pediatrics issue in which their article appeared, there was a report of a mother with hyperphenylalaninemia who had 2 normal children. In 8 women out of 20 with maternal hyperphenylalaninemia, phenylalanine levels were greater than 10 mg per 100 ml. 12 normal children were born and 10 mentally retarded children were born. Dr. Hansen suggests that that termination of pregnancy in hyperphenylalaninemic mothers should not continue to be the treatment of choice. Buist and Jhaveri respond that Dr. Hansen does not provide all the data and that there are reports in which all the children of affected mothers were severely brain damaged. They contend that the controlled use of some form of phenylalanine-restricted diet during pregnancy should be the treatment of choice.