Abstract
A group of 90 patients over the age of 2 years with untreated phenylketonuria was
studied by 3 independent observers in 3 different ways for evidence of mental deterioration.
In a small subset (N=10), psychometric tests showed a fall in Intelligence or Developmental
Quotients between the ages of 4 and 18 years; the same was found in a matched group
of nonphenylketonuric patients from the same institution. In a second subset (N =
83), a Habit Score derived from the observations of the patients' caretakers showed
a small overall improvement in adaptive behaviour over an average span of 19 years.
In a third subset (N = 81), clinical assessment by one observer detected no significant
change in mental ability over an average span of 11 years. No evidence of progressive
mental deterioration was found in untreated phenylketonuria from middle childhood
to middle age.
See also Long Term Studies of Untreated Phenylketonuria II in the journal Neuropädiatrie, issue
3 1978 .
Keyword
Mental retardation - Phenylketonuria
