[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.
Pinto
A L
AL
Departmento de Pediatria, Universidade Federal do Paraná (UFPr), Curitiba, PR, Brasil.
Raymond
K M
KM
Bruck
I
I
Antoniuk
S A
SA
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