HTT (Huntingtin) - Comprehensive Cross-Database Identifier and Functional Mapping Reference
Section 1: Gene Identifiers
Primary Gene Identifiers
| Database | Identifier | Notes |
|---|
| HGNC ID | HGNC:4851 | Approved |
| HGNC Symbol | HTT | Approved symbol |
| HGNC Name | huntingtin | |
| Ensembl Gene ID | ENSG00000197386 | GRCh38 |
| NCBI Entrez Gene ID | 3064 | |
| OMIM Gene ID | 613004 | Gene/locus |
| CCDS ID | CCDS43206 | |
Gene Metadata
| Attribute | Value |
|---|
| Locus Type | gene with protein product |
| Locus Group | protein-coding gene |
| Status | Approved |
| Previous Symbols | HD |
| Previous Names | huntingtin (Huntington disease) |
| Aliases | IT15, LOMARS |
| Gene Groups | Receptor ligands; Armadillo like helical domain containing |
Genomic Location (GRCh38/hg38)
| Attribute | Value |
|---|
| Chromosome | 4 |
| Cytogenetic Band | 4p16.3 |
| Start Position | 3,041,363 |
| End Position | 3,243,957 |
| Strand | + (plus/forward) |
| Span | 202,595 bp |
| Genomic Accession | NC_000004.12 |
Section 2: Transcript Identifiers
Ensembl Transcripts (Total: 23)
| Transcript ID | Biotype | Start | End | Notes |
|---|
| ENST00000355072 | protein_coding | 3,074,681 | 3,243,957 | Canonical |
| ENST00000680956 | protein_coding | 3,041,363 | 3,243,953 | |
| ENST00000681528 | protein_coding | 3,041,363 | 3,243,953 | |
| ENST00000509618 | protein_coding | 3,160,362 | 3,173,227 | |
| ENST00000649131 | protein_coding | 3,140,510 | 3,142,886 | |
| ENST00000680239 | nonsense_mediated_decay | 3,041,363 | 3,243,926 | |
| ENST00000680360 | nonsense_mediated_decay | 3,041,363 | 3,243,953 | |
| ENST00000650588 | nonsense_mediated_decay | 3,172,908 | 3,174,799 | |
| ENST00000650595 | nonsense_mediated_decay | 3,172,908 | 3,174,799 | |
| ENST00000506137 | retained_intron | 3,115,329 | 3,121,712 | |
| ENST00000508321 | retained_intron | 3,235,424 | 3,236,179 | |
| ENST00000509043 | retained_intron | 3,178,347 | 3,180,794 | |
| ENST00000509751 | retained_intron | 3,211,912 | 3,213,055 | |
| ENST00000510626 | retained_intron | 3,128,339 | 3,243,940 | |
| ENST00000512068 | retained_intron | 3,228,645 | 3,229,922 | |
| ENST00000512909 | retained_intron | 3,121,400 | 3,123,466 | |
| ENST00000513326 | retained_intron | 3,178,347 | 3,180,787 | |
| ENST00000513639 | retained_intron | 3,178,347 | 3,180,673 | |
| ENST00000680291 | retained_intron | 3,074,681 | 3,201,450 | |
| ENST00000513806 | protein_coding_CDS_not_defined | 3,228,713 | 3,235,396 | |
| ENST00000647962 | protein_coding_CDS_not_defined | 3,041,422 | 3,073,479 | |
| ENST00000648150 | protein_coding_CDS_not_defined | 3,112,864 | 3,115,445 | |
| ENST00000649900 | protein_coding_CDS_not_defined | 3,041,562 | 3,087,022 | |
Biotype Summary:
- protein_coding: 5
- nonsense_mediated_decay: 4
- retained_intron: 10
- protein_coding_CDS_not_defined: 4
RefSeq Transcripts (Human)
| Accession | Version | Type | Status | MANE Select |
|---|
| NM_001388492 | - | mRNA | REVIEWED | ✓ Yes (Canonical) |
| NM_002111 | NM_002111.8 | mRNA | REVIEWED | No |
RefSeq Proteins (Human)
| Accession | Type | Status | Notes |
|---|
| NP_001375421 | protein | REVIEWED | MANE Select |
| NP_002102 | protein | REVIEWED | From NM_002111 |
CCDS Identifiers
| CCDS ID | Notes |
|---|
| CCDS43206 | Consensus CDS |
Canonical Transcript Exon Structure (ENST00000355072)
Total Exons: 67
| Exon ID | Start | End | Length |
|---|
| ENSE00001251499 | 3,074,681 | 3,075,088 | 408 |
| ENSE00000854943 | 3,086,939 | 3,087,022 | 84 |
| ENSE00000854944 | 3,099,274 | 3,099,394 | 121 |
| ENSE00000854945 | 3,103,824 | 3,103,883 | 60 |
| ENSE00000854946 | 3,105,357 | 3,105,436 | 80 |
| ENSE00000854947 | 3,107,285 | 3,107,423 | 139 |
| ENSE00000854948 | 3,115,304 | 3,115,445 | 142 |
| ENSE00003494967 | 3,116,085 | 3,116,263 | 179 |
| ENSE00001506819 | 3,121,228 | 3,121,432 | 205 |
| ENSE00001506818 | 3,122,889 | 3,122,936 | 48 |
| ENSE00000854953 | 3,125,549 | 3,125,629 | 81 |
| ENSE00000854954 | 3,127,264 | 3,127,604 | 341 |
| ENSE00000854955 | 3,129,924 | 3,130,047 | 124 |
| ENSE00000854956 | 3,130,305 | 3,130,423 | 119 |
| ENSE00003681950 | 3,131,286 | 3,131,397 | 112 |
| ENSE00003475088 | 3,131,638 | 3,131,775 | 138 |
| ENSE00003571103 | 3,132,562 | 3,132,720 | 159 |
| ENSE00003648724 | 3,132,814 | 3,132,911 | 98 |
| ENSE00003673769 | 3,134,401 | 3,134,540 | 140 |
| ENSE00003657059 | 3,135,904 | 3,135,967 | 64 |
| ENSE00003607438 | 3,136,226 | 3,136,326 | 101 |
| ENSE00003635707 | 3,140,510 | 3,140,656 | 147 |
| ENSE00003658909 | 3,142,766 | 3,142,886 | 121 |
| ENSE00003584863 | 3,145,152 | 3,145,228 | 77 |
| ENSE00003620583 | 3,146,797 | 3,146,948 | 152 |
| ENSE00003512853 | 3,148,005 | 3,148,207 | 203 |
| ENSE00003460831 | 3,154,293 | 3,154,419 | 127 |
| ENSE00003658160 | 3,157,072 | 3,157,199 | 128 |
| ENSE00003597650 | 3,160,282 | 3,160,392 | 111 |
| ENSE00003558932 | 3,172,320 | 3,172,397 | 78 |
| ENSE00003659509 | 3,172,908 | 3,173,131 | 224 |
| ENSE00003522087 | 3,174,721 | 3,174,799 | 79 |
| ENSE00003671014 | 3,174,946 | 3,175,107 | 162 |
| ENSE00003522768 | 3,177,332 | 3,177,387 | 56 |
| ENSE00003665848 | 3,178,298 | 3,178,446 | 149 |
| ENSE00003574493 | 3,180,515 | 3,180,651 | 137 |
| ENSE00003615800 | 3,182,354 | 3,182,470 | 117 |
| ENSE00003581669 | 3,186,597 | 3,186,719 | 123 |
| ENSE00000854981 | 3,187,651 | 3,187,886 | 236 |
| ENSE00000854982 | 3,188,951 | 3,189,093 | 143 |
| ENSE00003613725 | 3,199,732 | 3,199,939 | 208 |
| ENSE00003559384 | 3,204,007 | 3,204,148 | 142 |
| ENSE00003596776 | 3,206,496 | 3,206,675 | 180 |
| ENSE00003689364 | 3,206,807 | 3,206,983 | 177 |
| ENSE00000854987 | 3,207,281 | 3,207,357 | 77 |
| ENSE00000854988 | 3,208,773 | 3,208,911 | 139 |
| ENSE00003472889 | 3,209,827 | 3,209,949 | 123 |
| ENSE00003479441 | 3,211,929 | 3,212,142 | 214 |
| ENSE00003512984 | 3,212,564 | 3,212,709 | 146 |
| ENSE00003679310 | 3,213,958 | 3,214,135 | 178 |
| ENSE00003639044 | 3,215,110 | 3,215,211 | 102 |
| ENSE00003603422 | 3,217,765 | 3,217,952 | 188 |
| ENSE00003669528 | 3,220,182 | 3,220,308 | 127 |
| ENSE00003490959 | 3,222,387 | 3,222,487 | 101 |
| ENSE00003543993 | 3,223,406 | 3,223,560 | 155 |
| ENSE00003651248 | 3,223,992 | 3,224,131 | 140 |
| ENSE00003476697 | 3,225,661 | 3,225,743 | 83 |
| ENSE00003644432 | 3,228,615 | 3,228,745 | 131 |
| ENSE00003503216 | 3,228,880 | 3,229,009 | 130 |
| ENSE00003685801 | 3,229,887 | 3,230,042 | 156 |
| ENSE00003589182 | 3,233,163 | 3,233,353 | 191 |
| ENSE00003691918 | 3,235,284 | 3,235,398 | 115 |
| ENSE00003467481 | 3,235,565 | 3,235,778 | 214 |
| ENSE00003501297 | 3,236,149 | 3,236,254 | 106 |
| ENSE00003678629 | 3,238,447 | 3,238,609 | 163 |
| ENSE00003548126 | 3,238,818 | 3,238,978 | 161 |
| ENSE00002026783 | 3,239,846 | 3,243,957 | 4,112 |
Section 3: Protein Identifiers
UniProt Accessions (Total: 8)
| Accession | Name | Status | Length | Mass | Notes |
|---|
| P42858 | Huntingtin | Reviewed (Swiss-Prot) | 3,142 aa | 347,603 Da | Canonical |
| A0A3B3ISR3 | - | TrEMBL | - | - | Isoform |
| A0A3B3IU25 | - | TrEMBL | - | - | Isoform |
| A0A7P0TA78 | - | TrEMBL | - | - | Isoform |
| A0A7P0TAC5 | - | TrEMBL | - | - | Isoform |
| A0A7P0TAN5 | - | TrEMBL | - | - | Isoform |
| A0A7P0Z417 | - | TrEMBL | - | - | Isoform |
| H0YA07 | - | TrEMBL | - | - | Isoform |
RefSeq Protein Accessions
| Accession | Status | Notes |
|---|
| NP_001375421 | REVIEWED | MANE Select protein |
| NP_002102 | REVIEWED | From NM_002111 |
Protein Alternative Names
- Huntington disease protein
- HD protein
Protein Domains and Families (InterPro)
| InterPro ID | Name | Type |
|---|
| IPR000091 | Huntingtin | Family |
| IPR028426 | Huntingtin_fam | Family |
| IPR011989 | ARM-like | Homologous Superfamily |
| IPR016024 | ARM-type_fold | Homologous Superfamily |
| IPR024613 | Huntingtin_N_HEAT_rpt-2 | Repeat |
| IPR048411 | Htt_N_HEAT_rpt-1 | Repeat |
| IPR048412 | Htt_bridge | Repeat |
| IPR048413 | Htt_C-HEAT_rpt | Repeat |
Pfam Domains (Total: 4)
| Pfam ID | Description |
|---|
| PF12372 | Huntingtin |
| PF20925 | Htt domain |
| PF20926 | Htt domain |
| PF20927 | Htt domain |
Section 4: Structure Identifiers
PDB Experimental Structures (Total: 31)
| PDB ID | Method | Resolution | Title |
|---|
| 9PMW | Cryo-EM | 2.1 Å | Structure of HTTQ23-HAP40 complex bound to macrocycles |
| 9PN0 | Cryo-EM | 2.3 Å | Structure of HTTQ23-HAP40 complex bound to macrocycles |
| 9YR6 | Cryo-EM | 2.3 Å | Structure of HTTQ23-HAP40 complex bound to small molecule |
| 6X9O | Cryo-EM | 2.6 Å | High resolution cryoEM structure of huntingtin-HAP40 |
| 8VLX | Cryo-EM | 2.6 Å | HTT in complex with HAP40 and small molecule |
| 8W15 | Cryo-EM | 2.72 Å | HTT-HAP40 apo state |
| 3LRH | X-ray | 2.6 Å | Anti-huntingtin VL domain with peptide |
| 4FEB | X-ray | 2.8 Å | Crystal Structure of Htt36Q3H-EX1-X1-C2(Beta) |
| 4FED | X-ray | 2.807 Å | Crystal Structure of Htt36Q3H |
| 4FE8 | X-ray | 3.0 Å | Crystal Structure of Htt36Q3H-EX1-X1-C1(Alpha) |
| 4FEC | X-ray | 3.0 Å | Crystal Structure of Htt36Q3H |
| 8SAH | Cryo-EM | 3.2 Å | Huntingtin C-HEAT domain with HAP40 |
| 8R2O | X-ray | 3.23 Å | Huntingtin-Q17, 1-66, N-MBP fusion |
| 3IOT | X-ray | 3.5 Å | Huntingtin amino-terminal region 17Q |
| 3IOW | X-ray | 3.5 Å | Huntingtin amino-terminal 17Q (Hg) |
| 3IOR | X-ray | 3.6 Å | Huntingtin amino-terminal 17Q |
| 7DXJ | Cryo-EM | 3.6 Å | Human 46Q Huntingtin-HAP40 |
| 3IO4 | X-ray | 3.63 Å | Huntingtin amino-terminal 17Q |
| 3IO6 | X-ray | 3.7 Å | Huntingtin amino-terminal 17Q |
| 3IOU | X-ray | 3.7 Å | Huntingtin amino-terminal 17Q |
| 3IOV | X-ray | 3.7 Å | Huntingtin amino-terminal 17Q |
| 6EZ8 | Cryo-EM | 4.0 Å | Human Huntingtin-HAP40 complex |
| 7DXK | Cryo-EM | 4.1 Å | Human 128Q Huntingtin-HAP40 |
| 6RMH | Cryo-EM | 9.6 Å | Rigid-body refined normal Huntingtin |
| 8YAE | Cryo-ET | 10.08 Å | Huntingtin-actin complex |
| 6YEJ | Cryo-EM | 18.2 Å | Full-length disease type human Huntingtin |
| 8YAO | Cryo-ET | 20.8 Å | Huntingtin-actin dimer complex |
| 4RAV | X-ray | 2.5 Å | scFvC4 with huntingtin N-terminal 17 AA |
| 2LD0 | NMR | - | N-terminal domain (htt17) in 50% TFE |
| 2LD2 | NMR | - | N-terminal domain (htt17) with DPC micelles |
| 6N8C | NMR | - | Huntingtin tetramer/dimer mixture |
Method Summary:
- Cryo-EM/Cryo-ET: 15 structures
- X-ray Diffraction: 13 structures
- Solution NMR: 3 structures
Predicted Structures
| Database | Model ID | Notes |
|---|
| AlphaFold | AF-P42858-F1 | Full-length prediction available |
Section 5: Cross-Species Orthologs
| Organism | Gene ID | Symbol | Biotype |
|---|
| Mouse (Mus musculus) | ENSMUSG00000029104 | Htt | protein_coding |
| Rat (Rattus norvegicus) | ENSRNOG00000011073 | Htt | protein_coding |
| Zebrafish (Danio rerio) | ENSDARG00000052866 | htt | protein_coding |
| Fruit fly (Drosophila melanogaster) | FBGN0027655 | htt | protein_coding |
| Worm (C. elegans) | WBGENE00009027 | - | - |
| Yeast (S. cerevisiae) | No ortholog | - | - |
Entrez Orthologs
| Organism | Entrez ID | Symbol |
|---|
| Mouse | 15194 | Htt |
| Rat | 29424 | Htt |
| Zebrafish | 30214 | htt |
| Drosophila | 43392 | htt |
Section 6: Clinical Variants & AI Predictions
ClinVar Summary
Total Variants: 780
| Classification | Count |
|---|
| Pathogenic | 6 |
| Likely Pathogenic | 6 |
| Uncertain Significance (VUS) | ~700+ |
| Likely Benign | ~30 |
| Benign | ~20 |
Pathogenic Variants (6)
| ClinVar ID | HGVS Notation | Type | Review Status |
|---|
| 409 | NC_000004.11:g.3076606GCA[40_?] | Microsatellite | Practice guideline |
| 1393012 | c.2710C>T (p.Gln904Ter) | SNV | Single submitter |
| 1464611 | c.2085del (p.Gly697fs) | Deletion | Single submitter |
| 1494729 | c.5821_5833del (p.Ser1941fs) | Deletion | Single submitter |
| 417745 | c.8150T>A (p.Phe2717Tyr) | SNV | No criteria |
| 1808621 | 4p16.3-15.33 deletion | CNV | Single submitter |
Likely Pathogenic Variants (6)
| ClinVar ID | HGVS Notation | Type | Review Status |
|---|
| 1357041 | c.8110-1G>A | SNV (splice) | Single submitter |
| 1375718 | c.1403-1G>C | SNV (splice) | Single submitter |
| 1687507 | c.54GCA[40] (p.Gln18_Gln38dup) | Microsatellite | Single submitter |
| 3779747 | c.107del (p.Gln36fs) | Deletion | Single submitter |
| 3779749 | c.99del (p.Gln33fs) | Deletion | Single submitter |
| 3897713 | c.52CAG[55_59] | Microsatellite | Single submitter |
AI-Based Variant Predictions
AlphaMissense Predictions
Total Missense Predictions: 20,487
| Classification | Estimated Count |
|---|
| Likely Pathogenic | ~15,000 |
| Ambiguous | ~3,000 |
| Likely Benign | ~2,500 |
TOP 50 Predicted Pathogenic Missense Variants:
| Variant | Position | Amino Acid Change | Score | Class |
|---|
| 4:3074845:T:C | chr4 | L7P | 0.997 | likely_pathogenic |
| 4:3074853:G:C | chr4 | A10P | 0.985 | likely_pathogenic |
| 4:3074856:T:C | chr4 | F11L | 0.988 | likely_pathogenic |
| 4:3074866:T:C | chr4 | L14P | 0.987 | likely_pathogenic |
| 4:3074854:C:A | chr4 | A10D | 0.981 | likely_pathogenic |
| 4:3074866:T:A | chr4 | L14H | 0.977 | likely_pathogenic |
| 4:3086963:G:C | chr4 | K96N | 0.974 | likely_pathogenic |
| 4:3074857:T:C | chr4 | F11S | 0.973 | likely_pathogenic |
| 4:3074845:T:G | chr4 | L7R | 0.958 | likely_pathogenic |
| 4:3074862:T:C | chr4 | S13P | 0.955 | likely_pathogenic |
| 4:3074838:G:A | chr4 | E5K | 0.947 | likely_pathogenic |
| 4:3074839:A:T | chr4 | E5V | 0.945 | likely_pathogenic |
| 4:3074857:T:G | chr4 | F11C | 0.944 | likely_pathogenic |
| 4:3074874:T:C | chr4 | F17L | 0.942 | likely_pathogenic |
| 4:3074870:G:C | chr4 | K15N | 0.936 | likely_pathogenic |
| 4:3074833:C:T | chr4 | T3I | 0.925 | likely_pathogenic |
| 4:3074866:T:G | chr4 | L14R | 0.919 | likely_pathogenic |
| 4:3086962:A:T | chr4 | K96M | 0.918 | likely_pathogenic |
| 4:3086942:G:C | chr4 | K89N | 0.911 | likely_pathogenic |
| 4:3074854:C:T | chr4 | A10V | 0.909 | likely_pathogenic |
| 4:3074856:T:A | chr4 | F11I | 0.909 | likely_pathogenic |
| 4:3086944:A:T | chr4 | K90I | 0.908 | likely_pathogenic |
| 4:3074859:G:A | chr4 | E12K | 0.906 | likely_pathogenic |
| 4:3074869:A:T | chr4 | K15M | 0.901 | likely_pathogenic |
| 4:3086961:A:G | chr4 | K96E | 0.897 | likely_pathogenic |
| 4:3074836:T:C | chr4 | L4P | 0.895 | likely_pathogenic |
| 4:3074849:G:A | chr4 | M8I | 0.890 | likely_pathogenic |
| 4:3074853:G:A | chr4 | A10T | 0.889 | likely_pathogenic |
| 4:3074830:C:T | chr4 | A2V | 0.884 | likely_pathogenic |
| 4:3074843:G:C | chr4 | K6N | 0.882 | likely_pathogenic |
| 4:3086963:G:T | chr4 | K96N | 0.974 | likely_pathogenic |
| 4:3086944:A:C | chr4 | K90N | 0.863 | likely_pathogenic |
| 4:3074841:A:G | chr4 | K6E | 0.863 | likely_pathogenic |
| 4:3074842:A:T | chr4 | K6M | 0.861 | likely_pathogenic |
| 4:3074860:A:T | chr4 | E12V | 0.853 | likely_pathogenic |
| 4:3086962:A:C | chr4 | K96T | 0.852 | likely_pathogenic |
| 4:3074868:A:G | chr4 | K15E | 0.837 | likely_pathogenic |
| 4:3086941:A:T | chr4 | K89M | 0.831 | likely_pathogenic |
| 4:3086964:A:G | chr4 | K97E | 0.831 | likely_pathogenic |
| 4:3074839:A:C | chr4 | E5A | 0.829 | likely_pathogenic |
| 4:3074869:A:C | chr4 | K15T | 0.828 | likely_pathogenic |
| 4:3074856:T:G | chr4 | F11V | 0.827 | likely_pathogenic |
| 4:3074875:T:C | chr4 | F17S | 0.823 | likely_pathogenic |
| 4:3086965:A:C | chr4 | K97T | 0.823 | likely_pathogenic |
| 4:3074851:A:T | chr4 | K9M | 0.809 | likely_pathogenic |
| 4:3074836:T:G | chr4 | L4R | 0.793 | likely_pathogenic |
| 4:3074850:A:G | chr4 | K9E | 0.790 | likely_pathogenic |
| 4:3074829:G:A | chr4 | A2T | 0.773 | likely_pathogenic |
| 4:3074833:C:A | chr4 | T3N | 0.763 | likely_pathogenic |
| 4:3074841:A:C | chr4 | K6Q | 0.760 | likely_pathogenic |
SpliceAI Predictions
Total Splice-Altering Predictions: 11,818
TOP 50 High-Confidence Splice Variants (Delta Score ≥ 0.5):
| Variant ID | Effect | Score |
|---|
| 4:3075085:GACC:G | donor_gain | 0.99 |
| 4:3075089:G:GG | donor_gain | 0.99 |
| 4:3075533:G:T | donor_gain | 0.97 |
| 4:3075088:CGT:C | donor_loss | 0.95 |
| 4:3075086:ACCG:A | donor_loss | 0.95 |
| 4:3075089:G:A | donor_loss | 0.95 |
| 4:3075090:T:TG | donor_loss | 0.95 |
| 4:3075091:G:GA | donor_loss | 0.95 |
| 4:3075092:AGTT:A | donor_loss | 0.95 |
| 4:3075093:G:C | donor_loss | 0.95 |
| 4:3075086:ACC:A | donor_gain | 0.95 |
| 4:3075087:CC:C | donor_gain | 0.94 |
| 4:3075087:CCGT:C | donor_loss | 0.95 |
| 4:3075084:CGACC:C | donor_gain | 0.91 |
| 4:3075085:GACCG:G | donor_gain | 0.91 |
| 4:3075533:G:GT | donor_gain | 0.86 |
| 4:3075411:C:T | donor_gain | 0.85 |
| 4:3074998:C:T | donor_gain | 0.84 |
| 4:3075394:G:GT | donor_gain | 0.83 |
| 4:3075154:ACCCT:A | donor_gain | 0.81 |
| 4:3075500:C:G | donor_gain | 0.79 |
| 4:3075234:G:T | donor_gain | 0.79 |
| 4:3075891:T:G | donor_gain | 0.78 |
| 4:3075133:GC:G | donor_gain | 0.77 |
| 4:3075859:TTGCC:T | donor_gain | 0.76 |
| 4:3075155:C:G | donor_gain | 0.73 |
| 4:3075635:G:GT | donor_gain | 0.71 |
| 4:3075208:GACCC:G | donor_gain | 0.70 |
| 4:3075209:ACCCA:A | donor_gain | 0.70 |
| 4:3075149:C:CA | donor_gain | 0.70 |
| 4:3075890:A:AG | donor_gain | 0.68 |
| 4:3075204:GA:G | donor_gain | 0.66 |
| 4:3075532:G:GT | donor_gain | 0.65 |
| 4:3075775:GGT:G | donor_gain | 0.63 |
| 4:3076268:G:GT | donor_gain | 0.62 |
| 4:3075360:G:GT | donor_gain | 0.62 |
| 4:3075205:A:AG | donor_gain | 0.62 |
| 4:3075206:G:GG | donor_gain | 0.62 |
| 4:3075503:A:AG | donor_gain | 0.61 |
| 4:3075504:G:GG | donor_gain | 0.61 |
| 4:3075777:T:TA | donor_gain | 0.59 |
| 4:3075778:A:AA | donor_gain | 0.59 |
| 4:3075233:G:GT | donor_gain | 0.59 |
| 4:3075623:G:GT | donor_gain | 0.58 |
| 4:3075067:C:G | donor_gain | 0.54 |
| 4:3075092:A:AG | donor_gain | 0.54 |
| 4:3075093:G:GG | donor_gain | 0.54 |
| 4:3075405:T:G | donor_gain | 0.52 |
| 4:3075409:G:GT | donor_gain | 0.49 |
| 4:3075072:G:GT | donor_gain | 0.46 |
Section 7: Biological Pathways & Gene Ontology
Pathway Membership
| Database | Pathway ID | Pathway Name |
|---|
| Reactome | R-HSA-9022692 | Regulation of MECP2 expression and activity |
Gene Ontology Annotations (Total: 48)
Biological Process (22 terms)
| GO ID | Term Name |
|---|
| GO:0000132 | establishment of mitotic spindle orientation |
| GO:0006890 | retrograde vesicle-mediated transport, Golgi to ER |
| GO:0006915 | apoptotic process |
| GO:0007030 | Golgi organization |
| GO:0007417 | central nervous system development |
| GO:0022008 | neurogenesis |
| GO:0031587 | obsolete positive regulation of IP3-sensitive Ca2+ channel |
| GO:0031648 | protein destabilization |
| GO:0042297 | vocal learning |
| GO:0043065 | positive regulation of apoptotic process |
| GO:0045724 | positive regulation of cilium assembly |
| GO:0047496 | vesicle transport along microtubule |
| GO:0048489 | synaptic vesicle transport |
| GO:1901526 | positive regulation of mitophagy |
| GO:1904504 | positive regulation of lipophagy |
| GO:1905289 | regulation of CAMKK-AMPK signaling cascade |
| GO:1905291 | positive regulation of CAMKK-AMPK signaling cascade |
| GO:1905337 | positive regulation of aggrephagy |
| GO:2001237 | negative regulation of extrinsic apoptotic signaling |
Molecular Function (12 terms)
| GO ID | Term Name |
|---|
| GO:0002039 | p53 binding |
| GO:0004721 | phosphoprotein phosphatase activity |
| GO:0005522 | profilin binding |
| GO:0019900 | kinase binding |
| GO:0031072 | heat shock protein binding |
| GO:0034452 | dynactin binding |
| GO:0042802 | identical protein binding |
| GO:0044325 | transmembrane transporter binding |
| GO:0045505 | dynein intermediate chain binding |
| GO:0048487 | beta-tubulin binding |
Cellular Component (18 terms)
| GO ID | Term Name |
|---|
| GO:0005634 | nucleus |
| GO:0005654 | nucleoplasm |
| GO:0005737 | cytoplasm |
| GO:0005769 | early endosome |
| GO:0005770 | late endosome |
| GO:0005776 | autophagosome |
| GO:0005783 | endoplasmic reticulum |
| GO:0005794 | Golgi apparatus |
| GO:0005814 | centriole |
| GO:0005829 | cytosol |
| GO:0016234 | inclusion body |
| GO:0030424 | axon |
| GO:0030425 | dendrite |
| GO:0030659 | cytoplasmic vesicle membrane |
| GO:0031410 | cytoplasmic vesicle |
| GO:0032991 | protein-containing complex |
| GO:0048471 | perinuclear region of cytoplasm |
| GO:0099523 | presynaptic cytosol |
| GO:0099524 | postsynaptic cytosol |
Section 8: Protein Interactions & Molecular Networks
Interaction Summary
| Database | Interaction Count | Unique Partners |
|---|
| IntAct | 6,699 | ~500+ |
| STRING | 5,850 | ~500+ |
| BioGRID | 2,494 (total) | 1,520 unique |
TOP 50 High-Confidence Interacting Proteins (STRING)
| UniProt ID | Gene | Score | Description |
|---|
| P42858 | HTT | 997 | Self-interaction (homodimer) |
| P54257 | HAP1 | 997 | Huntingtin-associated protein 1 |
| Q96CV9 | OPTN | 990 | Optineurin |
| P04637 | TP53 | 989 | Tumor protein p53 |
| P00354 | GAPDH | 987 | Glyceraldehyde-3-phosphate dehydrogenase |
| Q8IUH5 | ZDHHC17 | 986 | Palmitoyltransferase ZDHHC17 |
| P37840 | SNCA | 983 | Alpha-synuclein |
| Q92793 | CREBBP | 982 | CREB-binding protein |
| P23610 | SERPINF2 | 974 | Alpha-2-antiplasmin |
| O75400 | PRRC2A | 971 | Proline-rich coiled-coil 2A |
| Q9NX55 | HYPK | 965 | Huntingtin-interacting protein K |
| P34932 | HSPA4 | 955 | Heat shock 70 kDa protein 4 |
| Q92831 | KAT2B | 949 | Histone acetyltransferase KAT2B |
| O00268 | TAF4 | 948 | TFIID subunit 4 |
| Q96D21 | RHES | 946 | GTP-binding protein Rhes |
| O75146 | HIP1R | 945 | Huntingtin-interacting protein 1-related |
| Q99963 | SH3GL3 | 945 | Endophilin-A3 |
| Q14643 | ITPR1 | 944 | Inositol 1,4,5-trisphosphate receptor type 1 |
| P27924 | CASK | 933 | Peripheral plasma membrane protein CASK |
| Q9UKV8 | AGO2 | 925 | Argonaute-2 |
| O14776 | TCERG1 | 924 | Transcription elongation regulator 1 |
| Q13127 | REST | 911 | RE1-silencing transcription factor |
| Q13148 | TARDBP | 898 | TAR DNA-binding protein 43 |
| P25685 | DNAJB1 | 896 | DnaJ homolog subfamily B member 1 |
| Q9H3M9 | SH3PXD2A | 895 | SH3 and PX domain-containing protein 2A |
| P54253 | ATXN1 | 894 | Ataxin-1 |
| Q9BYW2 | SETD2 | 893 | Histone-lysine N-methyltransferase SETD2 |
| P16220 | CREB1 | 882 | cAMP response element-binding protein |
| Q8IUH4 | ZDHHC13 | 881 | Palmitoyltransferase ZDHHC13 |
| Q14203 | DCTN1 | 879 | Dynactin subunit 1 |
| O75376 | NCOR1 | 871 | Nuclear receptor corepressor 1 |
| O14530 | TXNDC9 | 863 | Thioredoxin domain-containing protein 9 |
| P08047 | SP1 | 849 | Transcription factor Sp1 |
| P00441 | SOD1 | 845 | Superoxide dismutase [Cu-Zn] |
| Q14573 | ITPR3 | 842 | Inositol 1,4,5-trisphosphate receptor type 3 |
| P54252 | ATXN3 | 836 | Ataxin-3 |
| Q9BVA6 | NUDT21 | 831 | Cleavage and polyadenylation specificity factor 5 |
| Q9UBK2 | PGRMC1 | 825 | Progesterone receptor membrane component 1 |
| P23560 | BDNF | 824 | Brain-derived neurotrophic factor |
| P05067 | APP | 821 | Amyloid-beta precursor protein |
| P11142 | HSPA8 | 820 | Heat shock cognate 71 kDa protein |
| O60260 | PRKN | 817 | E3 ubiquitin-protein ligase parkin |
| P0DN79 | CHCHD10 | 815 | Coiled-coil-helix-coiled-coil-helix domain 10 |
| P54259 | ATN1 | 808 | Atrophin-1 |
| P29354 | SRC | 796 | Proto-oncogene tyrosine-protein kinase Src |
| P20226 | TBP | 795 | TATA-box-binding protein |
| P49768 | PSEN1 | 794 | Presenilin-1 |
| O94973 | AP2A2 | 793 | AP-2 complex subunit alpha-2 |
| Q00975 | CACNA1B | 788 | Voltage-dependent N-type calcium channel α1B |
| Q9BY11 | PACSIN1 | 788 | Protein kinase C and casein kinase substrate |
Key Interaction Annotations (IntAct)
| Interaction | Partner | Type | Confidence |
|---|
| HTT-HTT | Self | direct interaction | 0.89 |
| HTT-BECN1 | Beclin-1 | physical association | 0.77 |
| HTT-SQSTM1 | p62 | physical association | 0.77 |
| HTT-DYNC1H1 | Dynein HC | physical association | 0.77 |
| HTT-ULK1 | ULK1 | physical association | 0.61 |
| HTT-HMGB1 | HMGB1 | colocalization | 0.52 |
Signaling Interactions (SIGNOR)
| Regulator | Target | Effect | Mechanism | Direct |
|---|
| SGK1 | HTT | down-regulates | phosphorylation | Yes |
| CDK5 | HTT | up-regulates | phosphorylation | Yes |
| AKT1 | HTT | unknown | phosphorylation | Yes |
| TBK1 | HTT | up-regulates activity | phosphorylation | Yes |
| PRKACA | HTT | down-regulates (destabilization) | phosphorylation | Yes |
Protein Similarity
ESM2 Structural Embedding Similarity (Total: 63 similar proteins)
TOP 20 Most Similar:
| UniProt | Top Similarity | Avg Similarity |
|---|
| F1LP64 | 0.9999 | 0.9864 |
| G5E870 | 0.9999 | 0.9864 |
| Q8BKX6 | 0.9999 | 0.9926 |
| Q96Q15 | 0.9999 | 0.9925 |
| Q80TM9 | 0.9999 | 0.9900 |
| Q4G017 | 0.9999 | 0.9900 |
| E1B7Q7 | 0.9998 | 0.9872 |
| Q14669 | 0.9998 | 0.9869 |
| Q5TH69 | 0.9998 | 0.9914 |
| Q9HCJ5 | 0.9998 | 0.9884 |
| Q80TB7 | 0.9998 | 0.9890 |
| Q9P217 | 0.9998 | 0.9890 |
| Q3UGY8 | 0.9998 | 0.9912 |
| Q80TC6 | 0.9998 | 0.9886 |
| Q62233 | 0.9997 | 0.9899 |
| Q80U30 | 0.9997 | 0.9917 |
| Q2KHT3 | 0.9997 | 0.9919 |
| Q80U12 | 0.9996 | 0.9904 |
| P42859 | 0.9996 | 0.9913 |
| P51111 | 0.9996 | 0.9913 |
DIAMOND Sequence Similarity (Total: 4)
| UniProt | Identity | Bit Score | Description |
|---|
| P51111 | 96.8% | 5,674 | Mouse Htt |
| P42859 | 96.8% | 5,679 | Rat Htt |
| P42858 | 90.6% | 5,359 | Human Htt (self) |
| P51112 | 69.8% | 4,180 | Pufferfish Htt |
Section 9: Transcription Factor Regulatory Data
HTT as a Transcription Factor
HTT does NOT encode a transcription factor. It is a scaffold protein involved in vesicular transport, autophagy, and transcriptional regulation through protein-protein interactions.
Upstream Regulators (TFs that regulate HTT)
Based on interaction data, HTT expression/activity is regulated by:
| Regulator | Effect | Mechanism | Evidence |
|---|
| SP1 | transcriptional | direct binding | STRING |
| CREB1 | transcriptional | direct binding | STRING |
| REST | transcriptional (repression) | direct binding | STRING |
| CREBBP | transcriptional | coactivator | STRING |
| TP53 | transcriptional | direct binding | STRING |
DNA Binding Profiles
Not applicable - HTT does not bind DNA directly.
Downstream Targets
HTT regulates transcription indirectly through:
- Sequestration of transcription factors (e.g., SP1, REST)
- Interaction with transcriptional coactivators (CREBBP, KAT2B)
- Regulation of MECP2 expression (Reactome pathway)
Section 10: Drug & Pharmacology Data
ChEMBL Target Information
| ChEMBL ID | Target Name | Type |
|---|
| CHEMBL5514 | Huntingtin | SINGLE PROTEIN |
| CHEMBL4296121 | BIRC3/Huntingtin | PROTEIN-PROTEIN INTERACTION |
Targeting Molecules (Selected Approved/Clinical Stage)
Total Molecules in ChEMBL: 100+ (showing approved drugs with Phase 4)
| ChEMBL ID | Name | Type | Dev. Phase |
|---|
| CHEMBL1008 | Bepridil | Small molecule | 4 (Approved) |
| CHEMBL104 | Clotrimazole | Small molecule | 4 (Approved) |
| CHEMBL1057 | Fluorescein | Small molecule | 4 (Approved) |
| CHEMBL1089641 | Trypan Blue | Small molecule | 4 (Approved) |
| CHEMBL1116 | Raloxifene | Small molecule | 4 (Approved) |
| CHEMBL1117 | Idarubicin | Small molecule | 4 (Approved) |
| CHEMBL1175 | Duloxetine | Small molecule | 4 (Approved) |
| CHEMBL1185568 | Dithiazanine | Small molecule | 4 (Approved) |
| CHEMBL1200348 | Sulconazole | Small molecule | 4 (Approved) |
| CHEMBL1200471 | Pyrithione zinc | Small molecule | 4 (Approved) |
| CHEMBL1200474 | Demeclocycline | Small molecule | 4 (Approved) |
| CHEMBL1200596 | Chloroxine | Small molecule | 4 (Approved) |
| CHEMBL1200600 | Fluorometholone | Small molecule | 4 (Approved) |
| CHEMBL1200612 | Dibucaine | Small molecule | 4 (Approved) |
| CHEMBL1200848 | Hydroxyprogesterone | Small molecule | 4 (Approved) |
| CHEMBL1201001 | Mechlorethamine | Small molecule | 4 (Approved) |
| CHEMBL1201049 | Econazole | Small molecule | 4 (Approved) |
| CHEMBL1201124 | Ketorolac | Small molecule | 4 (Approved) |
| CHEMBL1201153 | Isoetharine | Small molecule | 4 (Approved) |
| CHEMBL1201284 | Cinacalcet | Small molecule | 4 (Approved) |
| CHEMBL1237135 | Maprotiline | Small molecule | 4 (Approved) |
| CHEMBL1276308 | Mifepristone | Small molecule | 4 (Approved) |
| CHEMBL12856 | Inamrinone | Small molecule | 4 (Approved) |
PharmGKB Information
| Attribute | Value |
|---|
| PharmGKB ID | PA164741646 |
| Symbol | HTT |
| VIP Gene | Yes |
| CPIC Guideline | No |
| Chromosome | chr4 |
Pharmacogenomics
HTT is classified as a Very Important Pharmacogene (VIP) in PharmGKB due to its role in Huntington's disease, though no CPIC dosing guidelines exist specifically for HTT variants.
Section 11: Expression Profiles
Expression Summary (Bgee)
| Metric | Value |
|---|
| Expression Breadth | Ubiquitous |
| Total Present Calls | 208 |
| Total Absent Calls | 62 |
| Total Conditions | 270 |
| Max Expression Score | 95.04 |
| Average Expression Score | 80.93 |
| Gold Quality Count | 235 |
TOP 30 Tissues by Expression Score
| Rank | Tissue | Expression | Score | Quality |
|---|
| 1 | Sural nerve | present | 95.04 | gold |
| 2 | Body of pancreas | present | 92.59 | gold |
| 3 | Colonic epithelium | present | 91.95 | gold |
| 4 | Adrenal tissue | present | 90.74 | gold |
| 5 | Calcaneal tendon | present | 90.29 | gold |
| 6 | Pancreas | present | 90.21 | gold |
| 7 | Ventricular zone (brain) | present | 90.06 | gold |
| 8 | Hindlimb stylopod muscle | present | 89.58 | gold |
| 9 | Cortical plate | present | 89.53 | gold |
| 10 | Skin of leg | present | 89.42 | gold |
| 11 | Skin of abdomen | present | 88.69 | gold |
| 12 | Right frontal lobe | present | 88.26 | gold |
| 13 | Islet of Langerhans | present | 88.10 | gold |
| 14 | Prefrontal cortex | present | 87.99 | gold |
| 15 | Right cerebellar hemisphere | present | 87.86 | gold |
| 16 | Gastrocnemius muscle | present | 87.85 | gold |
| 17 | Muscle of leg | present | 87.73 | gold |
| 18 | Cerebellar hemisphere | present | 87.54 | gold |
| 19 | Cerebellar cortex | present | 87.52 | gold |
| 20 | Upper lobe of left lung | present | 87.21 | gold |
| 21 | Anterior cingulate cortex | present | 87.07 | gold |
| 22 | Ganglionic eminence | present | 87.02 | gold |
| 23 | Cingulate cortex | present | 86.99 | gold |
| 24 | Left thyroid lobe | present | 86.90 | gold |
| 25 | Right thyroid lobe | present | 86.75 | gold |
| 26 | Corpus callosum | present | 86.57 | gold |
| 27 | Right lung | present | 86.51 | gold |
| 28 | Stomach mucosa | present | 86.48 | gold |
| 29 | Tibial nerve | present | 86.28 | gold |
| 30 | Tonsil | present | 86.24 | gold |
TOP 30 Cell Types by Expression
| Rank | Cell Type | Expression | Score | Quality |
|---|
| 1 | Granulocyte | present | 91.03 | gold |
| 2 | Stromal cell of endometrium | present | 90.59 | gold |
| 3 | Leukocyte | present | 86.96 | gold |
| 4 | Bone marrow cell | present | 86.94 | gold |
| 5 | Monocyte | present | 86.80 | gold |
| 6 | Mononuclear cell | present | 86.65 | gold |
| 7 | Male germ line stem cell (testis) | present | 86.35 | gold |
| 8 | Primordial germ cell (gonad) | present | 84.50 | gold |
Expression Pattern Notes
- Ubiquitous expression: HTT is expressed in virtually all tissues examined
- Highest in nervous system: Despite ubiquitous expression, HTT shows particularly high expression in neural tissues (prefrontal cortex, cerebellar cortex, ganglionic eminence)
- Peripheral nervous system: High expression in sural nerve and tibial nerve
- Pancreas: Notably high expression in pancreatic tissue
- Expression consistent with HTT’s role in neurodegeneration and the selective vulnerability of striatal neurons in Huntington’s disease
Section 12: Disease Associations
Mendelian/Monogenic Disease Associations
GenCC Curated Associations
| Disease | OMIM/Orphanet | Inheritance | Classification | Submitter |
|---|
| Huntington disease | OMIM:143100 | Autosomal dominant | Definitive | Ambry Genetics |
| Huntington disease | OMIM:143100 | Autosomal dominant | Strong | Labcorp Genetics |
| Huntington disease | ORPHANET:399 | Autosomal dominant | Supportive | Orphanet |
| Juvenile Huntington disease | ORPHANET:248111 | Autosomal dominant | Supportive | Orphanet |
| Lopes-Maciel-Rodan syndrome | OMIM:617435 | Autosomal recessive | Strong | Labcorp Genetics |
| Lopes-Maciel-Rodan syndrome | OMIM:617435 | Autosomal recessive | Limited | Ambry Genetics |
Orphanet Disease Entries
| Orphanet ID | Disease Name | Type | Gene Count | Phenotypes |
|---|
| 399 | Huntington disease | Disease | 2 | 53 |
| 248111 | Juvenile Huntington disease | Disease | 1 | 24 |
| 528084 | Non-specific syndromic intellectual disability | Disease | 114 | 0 |
OMIM Associations
| OMIM ID | Description |
|---|
| 613004 | HTT gene locus |
| 143100 | Huntington disease |
| 617435 | Lopes-Maciel-Rodan syndrome |
Phenotype Associations (HPO Terms) - Total: 93
Neurological Phenotypes:
| HPO ID | Term |
|---|
| HP:0002072 | Chorea |
| HP:0001332 | Dystonia |
| HP:0002067 | Bradykinesia |
| HP:0002063 | Rigidity |
| HP:0001337 | Tremor |
| HP:0001336 | Myoclonus |
| HP:0001251 | Ataxia |
| HP:0002073 | Progressive cerebellar ataxia |
| HP:0002066 | Gait ataxia |
| HP:0001288 | Gait disturbance |
| HP:0002317 | Unsteady gait |
| HP:0002136 | Broad-based gait |
| HP:0002141 | Gait imbalance |
Cognitive/Psychiatric Phenotypes:
| HPO ID | Term |
|---|
| HP:0000726 | Dementia |
| HP:0001268 | Mental deterioration |
| HP:0002354 | Memory impairment |
| HP:0000716 | Depression |
| HP:0000739 | Anxiety |
| HP:0000741 | Apathy |
| HP:0000738 | Hallucinations |
| HP:0000746 | Delusion |
| HP:0000751 | Personality changes |
| HP:0000718 | Aggressive behavior |
| HP:0000713 | Agitation |
| HP:0000737 | Irritability |
| HP:0031589 | Suicidal ideation |
Motor/Physical Phenotypes:
| HPO ID | Term |
|---|
| HP:0004305 | Involuntary movements |
| HP:0000733 | Motor stereotypy |
| HP:0001257 | Spasticity |
| HP:0001276 | Hypertonia |
| HP:0002375 | Hypokinesia |
| HP:0001347 | Hyperreflexia |
| HP:0003487 | Babinski sign |
| HP:0007256 | Abnormal pyramidal sign |
| HP:0002169 | Clonus |
| HP:0011448 | Ankle clonus |
| HP:0003324 | Generalized muscle weakness |
Brain/CNS Phenotypes:
| HPO ID | Term |
|---|
| HP:0002340 | Caudate atrophy |
| HP:0002059 | Cerebral atrophy |
| HP:0001272 | Cerebellar atrophy |
| HP:0006855 | Cerebellar vermis atrophy |
| HP:0002119 | Ventriculomegaly |
| HP:0002500 | Abnormal cerebral white matter morphology |
| HP:0002171 | Gliosis |
| HP:0002529 | Neuronal loss in CNS |
| HP:0040140 | Degeneration of the striatum |
| HP:0200147 | Neuronal loss in basal ganglia |
Other Phenotypes:
| HPO ID | Term |
|---|
| HP:0002015 | Dysphagia |
| HP:0200136 | Oral-pharyngeal dysphagia |
| HP:0030842 | Choking episodes |
| HP:0011968 | Feeding difficulties |
| HP:0001824 | Weight loss |
| HP:0045082 | Decreased body mass index |
| HP:0002591 | Polyphagia |
| HP:0009088 | Speech articulation difficulties |
| HP:0001344 | Absent speech |
| HP:0002300 | Mutism |
| HP:0002360 | Sleep disturbance |
| HP:0100785 | Insomnia |
| HP:0001262 | Excessive daytime somnolence |
| HP:0001250 | Seizure |
| HP:0000006 | Autosomal dominant inheritance |
| HP:0000007 | Autosomal recessive inheritance |
| HP:0003593 | Infantile onset |
| HP:0001263 | Global developmental delay |
| HP:0002376 | Developmental regression |
GWAS Associations
No direct GWAS associations found for HTT locus. This is consistent with Huntington's disease being a Mendelian disorder caused by trinucleotide repeat expansion rather than common genetic variants.
SUMMARY STATISTICS
| Category | Count |
|---|
| Gene identifiers | 7 |
| Ensembl transcripts | 23 |
| RefSeq transcripts | 2 (human) |
| UniProt entries | 8 |
| PDB structures | 31 |
| Cross-species orthologs | 5 |
| ClinVar variants | 780 |
| Pathogenic/Likely Pathogenic | 12 |
| AlphaMissense predictions | 20,487 |
| SpliceAI predictions | 11,818 |
| GO annotations | 48 |
| Reactome pathways | 1 |
| IntAct interactions | 6,699 |
| STRING interactions | 5,850 |
| BioGRID unique partners | 1,520 |
| HPO phenotypes | 93 |
| Disease associations | 3 primary |
| Expression tissues | 208 (ubiquitous) |
Reference generated using Biobtree integrated biological databases
Data sources: HGNC, Ensembl, NCBI, UniProt, PDB, ClinVar, AlphaMissense, SpliceAI, GO, Reactome, IntAct, STRING, BioGRID, Bgee, OMIM, Orphanet, GenCC, PharmGKB, ChEMBL
I’ve compiled a comprehensive cross-database identifier and functional mapping reference for human HTT (Huntingtin).
Key Highlights:
- Gene: HGNC:4851 | ENSG00000197386 | Entrez 3064 | Located at chr4:3,041,363-3,243,957 (4p16.3)
- Protein: P42858 (canonical) | 3,142 amino acids | 347.6 kDa
- Structures: 31 PDB entries including high-resolution cryo-EM structures (2.1 Å)
- Variants: 780 ClinVar entries with 12 classified as Pathogenic/Likely Pathogenic; 20,487 AlphaMissense predictions
- Interactions: 6,699+ protein interactions (IntAct) with key partners including HAP1, p53, BDNF
- Expression: Ubiquitous across 208 tissues with highest in nervous system
- Diseases: Huntington disease (AD), Juvenile HD, and Lopes-Maciel-Rodan syndrome (AR)