Abstract
Serine deficiency disorders comprise a new group of inborn errors of serine metabolism.
Patients affected with these disorders present with major neurological symptoms including
congenital microcephaly, seizures, psychomotor retardation or polyneuropathy. The
diagnosis of serine deficiency is based on the detection of low concentrations of
the amino acids serine and glycine in fasted plasma and cerebrospinal fluid (CSF).
Amino acid analysis of cerebrospinal fluid is preferable over plasma analysis, because
the deficiencies are more pronounced in CSF. Because of the interference of amino
acids absorbed from the diet, diagnostic procedures have to be performed in the fasted
state. Although the disorders are probably rare and not many cases have been reported,
recognition of serine deficiency is important, given the fact that the disorders are
potentially treatable. The clinical symptoms respond well to amino acid replacement
therapy. So far, three serine deficiency disorders have been reported; 3-phosphoglycerate
dehydrogenase deficiency, 3-phosphoserine phosphatase deficiency and a still unexplained
serine deficiency disorder. In this paper, we will discuss the various serine deficiency
disorders, their biochemical abnormalities and the results of amino acid replacement
therapy.
Key words
Serine biosynthesis - Serine deficiency - 3-phosphoglycerate dehydrogenase - 3-phosphoserine
phosphatase
