A Screening Method for Biotinidase Deficiency in Newborns

We describe a method for neonatal screening for biotinidase (EC 3.5.1.12) deficiency. Biotinidase activity is assessed colorimetrically from dried samples of whole blood spotted on the same filter papers as used inthe neonatal screening for phenylketonuria. After the reaction, samples from normal infants are characteristically purple, whereas those from affected individuals are straw-colored. To confirm the defi-ciency, the enzyme is quantitatively assayed in additional blood spots or serum. A pilot study has been initiated with samples obtained by the Commonwealth of Virginia for phenylketonuria testing Additional Keyphrases: heritable disorders colorimetsy screening Late-onset, biotin-responsive, multiple carboxylase defi-ciency (LMCD)3 is an inherited, autosomal recessive disor-der characterized by skin rash, conjunctivitis, alopecia, ataxia, and often candidiasis and developmental delay (1,2). Symptoms usually first appear during the first several postnatal months, but may not occur for several years. Patients with the disorder may exhibit ketolactic acidosis and organic acidemia, caused by deficient activities of the biotin-dependent enzymes propionyl CoA carboxylase (EC 4.6.1.3), pyruvate carboxylase (EC 4.6.1.1), and /3-methyl