Neonatal Corneal Clouding as the Initial Manifestation of Biotinidase Deficiency.

Biotinidase deficiency is a treatable metabolic disorder associated with neurological and ophthalmic manifestations. The authors describe a newborn presenting with corneal clouding at birth. To the best of the authors' knowledge, only one similar case has previously been reported in the literature. Biotinidase activity was markedly reduced, and genetic testing confirmed a pathogenic biotinidase deficiency variant. Corneal opacity resolved completely after biotin therapy, indicating a rare but reversible ocular manifestation. Biotinidase deficiency should be considered in the differential diagnosis of neonatal corneal clouding. Early recognition is critical because prompt biotin therapy may lead to complete reversal of ocular findings and prevent irreversible neurological complications.