Biotinidase activity in patients with phenylketonuria

Biotin recycling impairment in phenylketonuric children with seborrheic dermatitis

“…According to our findings, the dermatologic problems often observed in PKU patients with elevated Phe levels were reflected by an altered plasma biotinidase activity, but not by serum biotin levels. Furthermore, these in vitro findings support the suggestion made elsewhere 7 that increased plasma Phe may influence biotinidase activity, acting as an enzyme inhibitor. Finally, it is expected that biotin supplementation in PKU patients with seborrheic dermatitis will have no beneficial effect.…”

“…4,5 Phenylketonuric (PKU) patients who do not strictly adhere to the above special diet often exhibit dermatologic problems In addition, according to our preliminary data, biotinidase activity was found to be normal in PKU patients with good compliance to the special diet, but was decreased in PKU patients who did not adhere well to this treatment. 6,7 In an attempt to explain the seborrheic dermatitis in PKU patients on a ''loose'' diet, we determined the serum biotin levels as well as the effect of the Phe concentration in biotinidase activity.…”

“…In other words, there must be a large reduction in animal products (meat, milk, eggs) in the diet and an increase in the intake of foodstuffs of vegetable origin (vegetarian diet) 4 , 5 . Phenylketonuric (PKU) patients who do not strictly adhere to the above special diet often exhibit dermatologic problems In addition, according to our preliminary data, biotinidase activity was found to be normal in PKU patients with good compliance to the special diet, but was decreased in PKU patients who did not adhere well to this treatment 6 , 7 …”