Disorders affecting vitamin B₆ metabolism.

Area of Science:

• Biochemistry
• Neuroscience
• Genetics

Background:

• Vitamin B6 exists in multiple dietary forms, but only pyridoxal 5'-phosphate (PLP) serves as an essential enzyme cofactor.
• PLP's reactive aldehyde group is vital for amino acid, neurotransmitter, and other metabolic pathways.
• Beyond its cofactor role, B6 vitamers function as antioxidants and influence gene expression and immune function.

Purpose of the Study:

• To review the clinical and biochemical features of inborn errors causing PLP deficiency.
• To describe the treatment strategies for B6-responsive epilepsy linked to PLP metabolism disorders.
• To highlight the importance of PLP in neurological function and the management of related genetic disorders.

Main Methods:

• Literature review of inborn errors affecting PLP metabolism and function.
• Analysis of clinical manifestations, including B6-responsive epilepsy.
• Examination of biochemical pathways involving PLP and its precursors/metabolites.

Main Results:

• Inborn errors in PLP synthesis, brain import, or inactivation lead to B6-responsive epilepsy.
• Specific genetic disorders discussed include pyridox(am)ine phosphate oxidase deficiency, ALDH7A1 deficiency, and others.
• Patients often require lifelong, high-dose vitamin B6 or PLP for seizure control.

Conclusions:

• PLP deficiency due to various genetic defects is a treatable cause of early-onset epilepsy.
• Prompt diagnosis and treatment with vitamin B6 or PLP are critical for managing these neurological disorders.
• Understanding PLP's multifaceted roles is essential for diagnosing and treating related metabolic and neurological conditions.