Should PNPO Deficiency Be Treated In Utero? Clinical Findings From Prenatal Pyridoxine Therapy

Area of Science:

• Biochemistry
• Genetics
• Neurology

Background:

• Pyridox(am)ine-5'-phosphate oxidase (PNPO) deficiency causes early-onset epileptic encephalopathy refractory to standard treatments.
• Genetic variants in the PNPO gene lead to deficient enzyme activity, impairing the conversion of vitamin B6 vitamers to the active cofactor, pyridoxal-5'-phosphate (PLP).
• Current treatments with PLP or pyridoxine have suboptimal long-term outcomes.

Purpose of the Study:

• To evaluate the efficacy and safety of in utero pyridoxine supplementation for PNPO deficiency.
• To assess the long-term neurodevelopmental outcomes in infants treated prenatally and postnatally.

Main Methods:

• Described two cases of unrelated children treated with vitamin B6 (pyridoxine) in utero.
• One patient had a confirmed prenatal PNPO diagnosis; the other was at risk due to family history.
• Treatment involved in utero pyridoxine followed by early postnatal PLP administration.

Main Results:

• Excellent seizure control and normal long-term neurodevelopment were achieved in the PNPO-deficient patient treated prenatally and postnatally.
• The first patient is the oldest reported PNPO-deficient individual treated from birth at 10 years old.
• Prenatal B6 supplementation was safe in an unaffected fetus, highlighting its potential in at-risk pregnancies.

Conclusions:

• Prenatal pyridoxine supplementation, combined with postnatal PLP, is a safe and potentially beneficial strategy for pregnancies at risk for PNPO deficiency.
• This approach may significantly improve seizure control and neurodevelopmental outcomes in affected infants.
• Further research is warranted to confirm these findings in larger cohorts.