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IEMbase 0034: PSPH-related phosphoserine phosphatase deficiency

Scope

Field Value
IEMbase ID 34
Nosology 1.6.03.01
Gene PSPH
External IDs OMIM:172480; OMIM:614023
Generated mapping UNMAPPED; best fuzzy candidate Pyruvate_Dehydrogenase_Deficiency.yaml
Candidate DisMech targets none currently valid
Review date 2026-07-07

IEMbase phenotype signal

IEMbase presents PSPH deficiency as a serine-biosynthesis disorder. The biochemical signature is low CSF serine and low-to-normal plasma serine.

The clinical signal is narrower than the PHGDH record: psychomotor delay, tonic-clonic seizures, growth retardation, and intellectual disability. IEMbase lists nutritional glycine and L-serine as treatments.

DisMech phenotype coverage

There is no local DisMech entry or subtype for PSPH-related phosphoserine phosphatase deficiency. The generated fuzzy candidate, Pyruvate_Dehydrogenase_Deficiency.yaml, should be rejected. It contains a PDH phosphatase regulatory subtype, but that is a mitochondrial pyruvate dehydrogenase complex disorder with lactic acidosis and impaired pyruvate oxidation, not a phosphoserine phosphatase defect in de novo serine synthesis.

Concordance and completeness

Judgement: generated unmapped status is correct, and the PDH candidate is a lexical false positive driven by the word phosphatase.

IEMbase supplies a compact phenotype set for a future PSPH curation target. Its distinguishing features are low CSF serine, relatively mild or variable plasma serine reduction, developmental delay, seizures, growth retardation, and serine/glycine supplementation.

Curation actions

  • Do not map this record to Pyruvate_Dehydrogenase_Deficiency.yaml.
  • Consider PSPH deficiency in the same future serine-biosynthesis work package as PHGDH and PSAT1 deficiency.
  • Preserve the distinction between low CSF serine and low-to-normal plasma serine if a future entry is created.