Component
SAM/SAH accumulation in human AHCY deficiency
Context-specific entity; species, compartment and exposure are stated on each claim.
2 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
What it acts on
Despite SAH accumulation, the index case showed leukocyte DNA hypermethylation, along with low plasma choline/phosphatidylcholine and high guanidinoacetate.
Experimental context and source evidence
- availability_state
- biomarker_context Imported condition classification; unverified.
- evidence_access
- Primary abstract
- experimental_model
- Human AHCY-deficiency case; different tissues and biochemical readouts.
- limitations
- No universal high-SAH-to-all-DNA-hypomethylation rule is inferred.
- nutrient_topic
- L-Methionine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Methionine
- plain_language
- A blood metabolite pattern does not predict every methylation endpoint in one direction.
- primary_references
- S-adenosylhomocysteine hydrolase deficiency in a human: a genetic disorder of methionine metabolism. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15024124/ · DOI 10.1073/pnas.0400658101
- trigger_kind
- biomarker_context Imported condition classification; unverified.
L-Methionine: transport, methylation, sulfur metabolism and cross-nutrient mechanisms (2026-09-19) · lines 188–194
AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human AHCY-deficiency case; different tissues and biochemical readouts. · source_derived_draft · unverified_draft
## methionine-ahcy-methylation-boundary A blood metabolite pattern does not predict every methylation endpoint in one direction. Despite SAH accumulation, the index case showed leukocyte DNA hypermethylation, along with low plasma choline/phosphatidylcholine and high guanidinoacetate. Model: Human AHCY-deficiency case; different tissues and biochemical readouts. Limitations: No universal high-SAH-to-all-DNA-hypomethylation rule is inferred. Evidence access: Primary abstract S-adenosylhomocysteine hydrolase deficiency in a human: a genetic disorder of methionine metabolism. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15024124/ · DOI 10.1073/pnas.0400658101
Complete structured claim and evidence
What acts on it
The index AHCY-deficient patient had very low enzyme activity and markedly elevated plasma SAH, SAM and methionine.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- evidence_access
- Primary abstract
- experimental_model
- Human infant, liver/red-cell/fibroblast assays and genetic analysis.
- limitations
- Single rare-disease case; not evidence of the same block in ordinary dietary variation.
- nutrient_topic
- L-Methionine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Methionine
- plain_language
- Abundant methyl-donor substrate can coexist with blocked recycling.
- primary_references
- S-adenosylhomocysteine hydrolase deficiency in a human: a genetic disorder of methionine metabolism. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15024124/ · DOI 10.1073/pnas.0400658101
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
L-Methionine: transport, methylation, sulfur metabolism and cross-nutrient mechanisms (2026-09-19) · lines 180–186
AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human infant, liver/red-cell/fibroblast assays and genetic analysis. · source_derived_draft · unverified_draft
## methionine-ahcy-loss Abundant methyl-donor substrate can coexist with blocked recycling. The index AHCY-deficient patient had very low enzyme activity and markedly elevated plasma SAH, SAM and methionine. Model: Human infant, liver/red-cell/fibroblast assays and genetic analysis. Limitations: Single rare-disease case; not evidence of the same block in ordinary dietary variation. Evidence access: Primary abstract S-adenosylhomocysteine hydrolase deficiency in a human: a genetic disorder of methionine metabolism. · 2004 · https://pubmed.ncbi.nlm.nih.gov/15024124/ · DOI 10.1073/pnas.0400658101
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.