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A cautionary tale of pyridoxine toxicity in cystathionine beta‐synthase deficiency detected by two‐tier newborn screening highlights the need for clear pyridoxine dosing guidelines
- Source :
- American Journal of Medical Genetics Part A. 182:2704-2708
- Publication Year :
- 2020
- Publisher :
- Wiley, 2020.
-
Abstract
- Classic homocystinuria is due to deficiency of cystathionine beta-synthase (CBS), a pyridoxine-dependent enzyme that, depending on the molecular variants, may be co-factor responsive. Elevated methionine is often used as the primary analyte to detect CBS deficiency (CBSD) on newborn screening (NBS), but is limited by increased detection of other biochemical disorders with less clear clinical significance such as methionine aminotransferase (MAT) I/III heterozygotes. Our state has implemented a two-tier NBS algorithm for CBSD that successfully reduced the number of MATI/III heterozygotes, yet effectively detected a mild, co-factor responsive form of CBSD. After initial diagnosis, newborns with CBSD often undergo a pyridoxine challenge with high-dose pyridoxine to determine responsiveness. Here we describe our NBS-identified patient with a mild form of pyridoxine responsive CBSD who developed respiratory failure and rhabdomyolysis consistent with pyridoxine toxicity during a pyridoxine challenge. This case highlights the need for weight-based dosing and duration recommendations for pyridoxine challenge in neonates.
- Subjects :
- Newborn screening
Methionine
biology
business.industry
Physiology
Homocystinuria
medicine.disease
Pyridoxine
Cystathionine beta synthase
chemistry.chemical_compound
chemistry
Genetics
medicine
biology.protein
Clinical significance
Hypermethioninemia
business
Rhabdomyolysis
Genetics (clinical)
medicine.drug
Subjects
Details
- ISSN :
- 15524833 and 15524825
- Volume :
- 182
- Database :
- OpenAIRE
- Journal :
- American Journal of Medical Genetics Part A
- Accession number :
- edsair.doi...........ab1a73a449026f70b42067d1282a89e6