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Biotin recycling impairment in phenylketonuric children with seborrheic dermatitis
Author(s) -
Schulpis Kleopatra H.,
Nyalala John O.,
Papakonstantinou Evangelos D.,
Leondiadis Leon,
Livaniou Evangelia,
Ithakisios Dionyssios,
Georgala Sophia
Publication year - 1998
Publication title -
international journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 93
eISSN - 1365-4632
pISSN - 0011-9059
DOI - 10.1046/j.1365-4362.1998.00603.x
Subject(s) - medicine , biotin , seborrheic dermatitis , biotinidase deficiency , group b , group a , endocrinology , phenylketonurias , phenylalanine , gastroenterology , dermatology , biochemistry , newborn screening , pediatrics , chemistry , amino acid
Objective To investigate the effect of a therapeutic diet on serum biotin levels and to explain the seborrheic dermatitis in phenylketonuric (PKU) patients on a “loose” diet. Design Forty‐seven patients were divided into two groups: group A ( n = 21) demonstrated good compliance to a special diet and group B ( n = 26) were on a “loose” diet. Most of the patients in group B (20/26), who suffered from mild seborrheic dermatitis, were requested to return to phenylalanine (Phe)‐restricted diet for at least 15 days. Seventy‐nine healthy children of comparable age were used as controls. Biotin serum levels and plasma biotinidase activity were measured in patients as well as controls. In addition, biotinidase activity was evaluated in vitro after incubation with various concentrations of Phe. Results Biotin levels in group A patients (636 ± 118 ng/L) were statistically significantly elevated ( P < 0.01) compared with those of group B patients before (412 ± 184 ng/L) and after (501 ± 160 ng/L) 15 days on a Phe‐restricted diet, as well as with those of controls (337 ± 290 ng/L). Furthermore, biotinidase activities were decreased in group B patients (4.2 ± 1.68 nmol/min/L) compared with those of group A patients (6.4 ± 0.7 nmol/min/L) and controls (6.10 ± 0.8 nmol/min/L). Additionally, biotinidase activities in the patients of group B were restored to normal (5.78 ± 0.81 nmol/min/L), with a simultaneous remission of their skin lesions, after 15 days on a Phe‐restricted diet. Moreover, the in vitro findings showed a 51% inhibition of biotinidase activity when incubated with Phe (20 mg/dL). Conclusions It is suggested that the high biotin levels in group A patients reflect the intake of water‐soluble biotin of vegetable origin. In contrast, the low biotinidase activity in group B patients may be attributed to their high Phe plasma levels, which acts as an enzyme inhibitor, as shown by the in vivo and in vitro results. Consequently, the observed seborrheic dermatitis in PKU children (group B) is associated with an impairment of biotin recycling.