Pathway candidateNCBI-verifiedprotein-coding

HDAC9

histone deacetylase 9

NCBI Gene: 9734 Ensembl GeneCards UniProt: Q9UKV0

Pathway candidate — not linked to PFS or PSSD by any record here

HDAC9 is in the library because it belongs to the epigenetic regulation family. No study, report or commentary in the corpus names it, so a variant in HDAC9 is not, by itself, evidence of anything related to post-drug syndromes.

Gene summary

A protein-coding gene on chromosome 7 (epigenetic regulation). Histones play a critical role in transcriptional regulation, cell cycle progression, and developmental events. Histone acetylation/deacetylation alters chromosome structure and affects transcription factor access to DNA.

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: Histone deacetylase 9
Function: Responsible for the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Represses MEF2-dependent transcription. Isoform 3 lacks active site residues and therefore is catalytically inactive. Represses MEF2-dependent transcription by recruiting HDAC1 and/or HDAC3. Seems to inhibit skeletal myogenesis and to be involved in heart development. Protects neurons from apoptosis, both by inhibiting JUN phosphorylation by MAPK10 and by repressing JUN transcription via HDAC1 recruitment to JUN promoter.
Subcellular location: Nucleus.
Tissue specificity: Broadly expressed, with highest levels in brain, heart, muscle and testis. Isoform 3 is present in human bladder carcinoma cells (at protein level).
Associated conditions: Auriculocondylar syndrome 4 (ARCND4).

Source: UniProtKB/Swiss-Prot Q9UKV0, release 2026_03, licensed CC BY 4.0. This is the protein’s normal biology, not evidence about post-drug syndromes; associated conditions are inherited disorders of the gene, not PFS, PSSD or PRSD.

Why its pathway is in the library

Epigenetic persistence is the leading hypothesis for why post-drug syndromes endure after the drug is gone; chromatin regulators are therefore priority candidates in any persistence mechanism.

Written for the whole epigenetic regulation family, not for HDAC9 specifically.

Mentioned in 0 corpus records

No corpus record names HDAC9 directly yet. It is in the library because it sits in a pathway the corpus tracks (Epigenetic regulation).

Also in epigenetic regulation

All 130 genes

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Gene summary

Source: NCBI Gene, accessed 2026-10-07.

Protein reference (UniProt)

Protein: Histone deacetylase 9
Function: Responsible for the deacetylation of lysine residues on the N-terminal part of the core histones (H2A, H2B, H3 and H4). Histone deacetylation gives a tag for epigenetic repression and plays an important role in transcriptional regulation, cell cycle progression and developmental events. Represses MEF2-dependent transcription. Isoform 3 lacks active site residues and therefore is catalytically inactive. Represses MEF2-dependent transcription by recruiting HDAC1 and/or HDAC3. Seems to inhibit skeletal myogenesis and to be involved in heart development. Protects neurons from apoptosis, both by inhibiting JUN phosphorylation by MAPK10 and by repressing JUN transcription via HDAC1 recruitment to JUN promoter.
Subcellular location: Nucleus.
Tissue specificity: Broadly expressed, with highest levels in brain, heart, muscle and testis. Isoform 3 is present in human bladder carcinoma cells (at protein level).
Associated conditions: Auriculocondylar syndrome 4 (ARCND4).