Three cases of untreated classical PKU: a report on cataracts and brain calcification.

There are only four previous reports of cataracts in untreated classical phenylketonuria (PKU) patients. Brain calcification, which has been known to occur in patients with dihydropteridine reductase (DHPR) deficiency, has been reported, as far as we know, in only one (albeit unusual) case. We report on three patients with untreated classical PKU; all have cataracts and normal serum levels of glucose and galactose. One of the patients (whose endocrinological tests and biochemistry including folate were normal) has bilateral brain calcifications remarkably similar to that seen in DHPR deficiency. To what extent cataracts and brain calcification occur with classical PKU is unknown because of the lack of case reports addressing these symptoms. Our cases combined with previous reports call attention to the fact that they may be frequently overlooked manifestations of classical PKU.