Determination of Biotinidase Enzyme Levels in Umbilical Cord Blood and Comparisons with Dried Blood Spot Testing in Newborns

Biotinidase deficiency (BD) is an autosomal recessive inherited metabolic disorder caused by enzymatic deficiency. Untreated patients may develop neurologic symptoms, hearing loss, optic atrophy, skin eruptions and/or alopecia. Although cord blood has been explored as a possible sampling type for various newborn screening tests, there is limited data on its use to measure biotinidase activity. In particular, there are no standard reference ranges or established cut-off values for BD detection in cord blood. In this prospective cohort study, we aimed to determine biotinidase activity levels in cord blood samples from newborns and to investigate their comparability with dried blood spot (DBS) measurements.