Cobalamin F disease detected by newborn screening and follow-up on a 14-year-old patient.

The cobalamin F (cblF) defect is caused by disturbed lysosomal release of cobalamin (vitamin B(12)) into the cytoplasm caused by mutations in the LMBRD1 gene. We present the clinical and biochemical characterization of a patient with newly diagnosed cblF disease and a follow-up on a 14-year-old patient. The new patient presented with elevation of propionyl carnitine found on a newborn screen.

Tetrahydrobiopterin therapy for phenylketonuria in infants and young children.

Objective: To describe patient selection, treatment administration, response evaluation, and side effect management associated with sapropterin therapy in infants and children aged <4 years.

Study Design: Six case reports are presented from 4 US metabolic clinics treating phenylketonuria with sapropterin in patients aged 7 months to 4 years. Outcomes included blood phenylalanine (Phe) levels before and during treatment.