COQ2 across dismech

COQ2 (coenzyme Q2, polyprenyltransferase) is named by 3 disorder entries.

Normal function

ai-gene-review gives COQ2's core molecular function as 4-hydroxybenzoate polyprenyltransferase activity, acting in ubiquinone biosynthetic process. This is the step that attaches the decaprenyl side chain to the 4-hydroxybenzoate ring of coenzyme Q10.

Causative records

Two entries type COQ2 as causative: COQ2-Related Primary Coenzyme Q10 Deficiency; and Primary Coenzyme Q10 Deficiency. Both record the variants as germline (COQ2-Related Primary Coenzyme Q10 Deficiency; and Primary Coenzyme Q10 Deficiency).

In the group entry, Primary Coenzyme Q10 Deficiency, the gene sits on Defective Polyisoprenoid Side-Chain Assembly and Attachment, together with the two decaprenyl diphosphate synthase subunits, and on the shared node Defective CoQ10 Biosynthesis. The gene-specific entry places it on COQ2 Polyprenyltransferase Deficiency.

Risk-factor record

Multiple System Atrophy types COQ2 as a risk factor, not a cause, on the node Mitochondrial Dysfunction and Coenzyme Q10 Deficiency.

Where the layers agree and disagree

The KB mechanism nodes and ai-gene-review share ubiquinone biosynthetic process as a GO process by exact identifier, so the dysfunction modelled in dismech is the loss of the gene's normal process.

ClinGen classifies COQ2 for 1 disease, and that disease has no matching dismech entry: mitochondrial disease. ClinGen's lumped "mitochondrial disease" is broader than any CoQ10 entry, so its tier is not copied onto the CoQ10 deficiency records.