sck@elsie.UUCP (Steve Kaufman) (07/29/85)
References: <771@burl.UUCP> <11518@brl-tgr.ARPA> <792@mtuxo.UUCP> <196@steinmetz.UUCP> In article <196@steinmetz.UUCP>, connolly@steinmetz.UUCP (C. Ian Connolly) writes: > > I know of a few people who claim to suffer adverse effects from drinking > diet soft drinks with Nutrasweet, but none of them know whether or not > they are Phenylketonurics. A) this is anecdotal, and must be taken with > a grain of salt, but this might indicate that B) PKU tests were not routine > until recently, or C) something other than PKU is the problem here. You bet this is anecdotal & should be taken with _at_least_ a grain of salt (perhaps using KCl instead of NaCl if you're hypertensive :) In the course of trying to find out how recently PKU screening became routine, I came acoss the following (as well as 2 other interesting tidbits which have been appended below): [Abbreviations: phe = phenylalanine # = number ] 1. A simple test for PKU well-suited to mass screening was described in 1961 by R. Guthrie: "Blood screening for PKU" (letter) JAMA 178:863 I do not know when mass screening of all newborns for PKU became routine but, at least in Massachusetts, "screening for virtually all disorders of amino acid and organic acid metabolism, galactosemia, and of other disorders" has been done since 1968. [Henry Nadler & Barbara Burton, "Genetics", 1980, p. 100 in _Fetal_and_Maternal_Medicine_, Quilligan & Kretchmer, eds., Wiley] 2. "In addition to those ... with classic PKU about an equal # ... have hyperphenylalaninemia without mental retardation or any other manifestations. Although such individuals are now also identified by neonatal screening, there would have been, in the past, no way of clinically recogniziing such an individual. It has been suggested that dietary restriction of phe during pregnancy in women with hyperphenylalaninemia may avert damage to the fetus. Adequate clinical studies in this population of pregnant women have not yet been reported. Because of the high risk of recurrence of mental retardation, a blood phe determination is indicatedin any woman who has given birth to [ a child ] with undiagnosed mental retardation." [Henry L. Nadler & Barbara K. Burton, "Genetics", pp. 68-9 in _Fetal_and_Maternal_Medicine_ 1980 Wiley] 3. "... public health programs have effectively prevented mental retardation associated with PKU since, in those states or countries that have instituted systematic programs, few cases [of retardation due to PKU] have been discovered in recent years. Previously, PKU contributed about 1% of the mentally retarded in institutions. [Zena A. Stein & Marvyn Susser "Mental Retardation", 1981 p. 298 in _Preventive_&_Commujity_Medicine_ Duncan Clark & Brian MacMahon, eds, Little] On the other hand, "it has been estimated that at least 5% of affected individuals may be missed by the screening procedures in operation in this country. Infants with PKU are born with normal phe levels and must be exposed to protein feedings for a certain period of time before elevated levels can be documented. The exact length of time required is dependent on the sex, protein intake [I have been told that breast-feeding prolongs the lag time], and a # of other factors. The current policy of early hospital discharge forces many infants to be screened at an earlier than optimal time. An additional problem in this country is the not infrequent delay in the institution of therapy in this country." [Nadler & Burton, "Genetics", p. 100 in _Fetal_and_Maternal_Medicine_ 1980 Wiley]