The main source of L-serine is de novo biosynthesis.

Besides its role in protein synthesis, serine is a neurotrophic factor and a precursor of a number of essential compounds.

Serine biosynthesis and transport defects present with neurological manifestations and growth delicacy.

Serine biosynthesis defects result in systemic serine deficiency and present in a broad phenotypic spectrum.

Serine transport defect results in neuronal serine deficiency and manifestations overlap with serine biosynthesis defects.