[Prevalence study of biotinidase deficiency in newborns].
BACKGROUND
Biotinidase deficiency is an inheritable disorder of biotin metabolism. This disorder fulfills major criteria for consideration for newborn screening: the affected children do no show clinical signs in the newborn period; the disease is highly disabling; treatment is effective in preventing neurological sequelae if undertaken promptly.


METHODS
Screening of 125,000 infants born in Paraná State was carried out to establish the prevalence of biotinidase deficiency. A simple colorimetric procedure was used to detect two infants with biotinidase deficiency (1:62,500), one of them with profound deficiency (1:125,000) and the other with partial deficiency (1:125,000) of the enzyme.


RESULTS
There were no known false-negative test results and 0.12% were false-positive, defined by further blood samples which were negative upon repeated testing. Sensitivity was 100% and specificity was 99.88%. Repeat blood samples could not be obtained in 63 (30%) suspected cases.


CONCLUSIONS
Newborn screening for biotinidase is useful in identifying affected children, is inexpensive and allows early intervention, which may prevent irreversible neurological damage.
Departmento de Pediatria, Universidade Federal do Paraná (UFPr), Curitiba, PR, Brasil.
A L
AL
Pinto
K M
KM
Raymond
I
I
Bruck
S A
SA
Antoniuk
D000581:Amidohydrolases / Q000172:deficiency* / Q000378:metabolism; D043523:Biotinidase; D003365:Costs and Cost Analysis; D006801:Humans; D007231:Infant, Newborn; D008661:Metabolism, Inborn Errors / Q000453:epidemiology* / Q000628:therapy; D015997:Neonatal Screening; D015995:Prevalence; D011446:Prospective Studies
D000581:Amidohydrolases; D043523:Biotinidase