WP4228 - Vitamin B6-dependent and responsive disorders - Homo sapiens

Vitamin B6 is absorbed in different vitamers, which undergo several (de)phosphorylation steps, to be able to pas the blood-brain barrier. Within the brain, PLP (pyridoxal-P) is the only active cofactor for intracellular enzyme reactions. PLP catalyses over 100 reactions, mainly related to amino acids and neurotransmitter metabolism. Bold lines in the pathway diagram show how the major source of PLP is divided in the body.
A number of genetic defects have been identified as the underlying cause of vitamin B6 dependent epilepsies, particularly occurring in the neonatal life stage, which could lead to irreversible brain damage or death.
The disorders related to this pathway can be divided in two categories: reduced production/availability of PLP or inactivation of PLP by formation of Knoevenagel products.
Specific biomarkers from urine, plasma or cerebrospinal fluid (CSF) exist to distinguish the disorders.
Oral treatment with PL or PLP is available, as well as intrauterine treatment with vitamin B6 for mothers in the early stages of pregnancy.

This pathway was inspired by Ed. 5 Chapter 34 of the book of Blau (ISBN 9783030677268) (ed.4 Chapter 11).