Trait
IQ less than 20
Clinical name: Profound intellectual disability
Profound intellectual disability (ID) is defined as a type of ID characterized by profoundly sub-average adaptive functioning and intellectual functioning, with an intelligence quotient (IQ) below 20.
Summary
- Also called
- Intellectual disability, profound
- Body system
- Abnormality of the nervous system
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
Read the genes linked to IQ less than 20, and the rest of your genome, with one test.
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Get my Genome Test117 genes linked to IQ less than 20
Changes in these genes cause rare conditions in which IQ less than 20 is seen. Most people with this trait have none of those conditions, and a gene on this list says nothing about anyone's own genome.
| Gene | How often it is seen | Conditions |
|---|---|---|
| ADAM22ADAM metallopeptidase domain 22 | Always | In 1 condition |
| ARV1ARV1 fatty acid homeostasis modulator | Always | In 1 condition |
| ASXL1ASXL transcriptional regulator 1 | Always | In 2 conditions |
| ATIC5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase | Always | In 1 condition |
| ATP6V0CATPase H+ transporting V0 subunit c | Always | In 1 condition |
| ATXN7L3ataxin 7 like 3 | Always | In 1 condition |
| BORCS8BLOC-1 related complex subunit 8 | Always | In 1 condition |
| CACNA2D1calcium voltage-gated channel auxiliary subunit alpha2delta 1 | Always | In 1 condition |
| CCDC88Acoiled-coil and HOOK domain protein 88A | Always | In 1 condition |
| DHRSXdehydrogenase/reductase X-linked | Always | In 1 condition |
| DMXL2Dmx like 2 | Always | In 1 condition |
| DPH5diphthamide biosynthesis 5 | Always | In 1 condition |
| ELOVL4ELOVL fatty acid elongase 4 | Always | In 1 condition |
| FAR1fatty acyl-CoA reductase 1 | Always | In 1 condition |
| FDXRferredoxin reductase | Always | In 1 condition |
| FGF12fibroblast growth factor 12 | Always | In 1 condition |
| GAD1glutamate decarboxylase 1 | Always | In 1 condition |
| GTPBP2GTP binding protein 2 | Always | In 1 condition |
| INPP4Ainositol polyphosphate-4-phosphatase type I A | Always | In 1 condition |
| JKAMPJNK1/MAPK8 associated membrane protein | Always | In 1 condition |
| LARGE1LARGE xylosyl- and glucuronyltransferase 1 | Always | In 2 conditions |
| MCCC1methylcrotonyl-CoA carboxylase subunit 1 | Always | In 1 condition |
| MECP2methyl-CpG binding protein 2 | Always | In 1 condition |
| MED23mediator complex subunit 23 | Always | In 1 condition |
| MRAPmelanocortin 2 receptor accessory protein | Always | In 1 condition |
| NAPBNSF attachment protein beta | Always | In 1 condition |
| NDE1nudE neurodevelopment protein 1 | Always | In 1 condition |
| NSFN-ethylmaleimide sensitive factor, vesicle fusing ATPase | Always | In 1 condition |
| NUP133nucleoporin 133 | Always | In 1 condition |
| PIGAphosphatidylinositol glycan anchor biosynthesis class A | Always | In 1 condition |
| PIGGphosphatidylinositol glycan anchor biosynthesis class G (EMM blood group) | Always | In 1 condition |
| PRUNE1prune exopolyphosphatase 1 | Always | In 1 condition |
| RNF113Aring finger protein 113A | Always | In 1 condition |
| RNF13ring finger protein 13 | Always | In 2 conditions |
| RNU2-2RNA, U2 small nuclear 2 | Always | In 1 condition |
| SCN1Asodium voltage-gated channel alpha subunit 1 | Always | In 1 condition |
| SPTAN1spectrin alpha, non-erythrocytic 1 | Always | In 1 condition |
| STRA6signaling receptor and transporter of retinol STRA6 | Always | In 1 condition |
| STXBP1syntaxin binding protein 1 | Always | In 1 condition |
| SYNJ1synaptojanin 1 | Always | In 1 condition |
Show 77 more genes
| Gene | How often it is seen | Conditions |
|---|---|---|
| TBCKTBC1 domain containing kinase | Always | In 1 condition |
| THAP11THAP domain containing 11 | Always | In 1 condition |
| TRAPPC4trafficking protein particle complex subunit 4 | Always | In 1 condition |
| UBTFupstream binding transcription factor | Always | In 2 conditions |
| WASHC4WASH complex subunit 4 | Always | In 1 condition |
| WDR45BWD repeat domain 45B | Always | In 1 condition |
| ADARadenosine deaminase RNA specific | Very often (80–99%) | In 1 condition |
| AP1S2adaptor related protein complex 1 subunit sigma 2 | Very often (80–99%) | In 2 conditions |
| ATP6V0A2ATPase H+ transporting V0 subunit a2 | Very often (80–99%) | In 1 condition |
| ATP6V1AATPase H+ transporting V1 subunit A | Very often (80–99%) | In 1 condition |
| ATP6V1E1ATPase H+ transporting V1 subunit E1 | Very often (80–99%) | In 1 condition |
| DIAPH1diaphanous related formin 1 | Very often (80–99%) | In 1 condition |
| FGFR3fibroblast growth factor receptor 3 | Very often (80–99%) | In 3 conditions |
| IFIH1interferon induced with helicase C domain 1 | Very often (80–99%) | In 1 condition |
| LSM11LSM11, U7 small nuclear RNA associated | Very often (80–99%) | In 1 condition |
| PIGUphosphatidylinositol glycan anchor biosynthesis class U | Very often (80–99%) | In 1 condition |
| PRPS1phosphoribosyl pyrophosphate synthetase 1 | Very often (80–99%) | In 1 condition |
| RNASEH2Aribonuclease H2 subunit A | Very often (80–99%) | In 1 condition |
| RNASEH2Bribonuclease H2 subunit B | Very often (80–99%) | In 1 condition |
| RNASEH2Cribonuclease H2 subunit C | Very often (80–99%) | In 1 condition |
| RNU7-1RNA, U7 small nuclear 1 | Very often (80–99%) | In 1 condition |
| SAMHD1SAM and HD domain containing deoxynucleoside triphosphate triphosphohydrolase 1 | Very often (80–99%) | In 1 condition |
| SLC39A8solute carrier family 39 member 8 | Very often (80–99%) | In 2 conditions |
| SLC9A6solute carrier family 9 member A6 | Very often (80–99%) | In 1 condition |
| TREX1three prime repair exonuclease 1 | Very often (80–99%) | In 2 conditions |
| ASXL3ASXL transcriptional regulator 3 | Often (30–79%) | In 1 condition |
| CLIC2CLIC family member 2 | Often (30–79%) | In 1 condition |
| DPM3dolichyl-phosphate mannosyltransferase subunit 3, regulatory | Often (30–79%) | In 1 condition |
| EMC1ER membrane protein complex subunit 1 | Often (30–79%) | In 1 condition |
| EXOSC5exosome component 5 | Often (30–79%) | In 1 condition |
| KCNJ6potassium inwardly rectifying channel subfamily J member 6 | Often (30–79%) | In 1 condition |
| LONP1lon peptidase 1, mitochondrial | Often (30–79%) | In 1 condition |
| NACC1nucleus accumbens associated 1 | Often (30–79%) | In 1 condition |
| NGLY1N-glycanase 1 | Often (30–79%) | In 1 condition |
| PDHA1pyruvate dehydrogenase E1 subunit alpha 1 | Often (30–79%) | In 1 condition |
| PUS3pseudouridine synthase 3 | Often (30–79%) | In 2 conditions |
| SCN8Asodium voltage-gated channel alpha subunit 8 | Often (30–79%) | In 1 condition |
| SETD1BSET domain containing 1B, histone lysine methyltransferase | Often (30–79%) | In 1 condition |
| SLC1A2solute carrier family 1 member 2 | Often (30–79%) | In 1 condition |
| TBC1D20TBC1 domain family member 20 | Often (30–79%) | In 1 condition |
| TBCDtubulin folding cofactor D | Often (30–79%) | In 1 condition |
| UNC13Aunc-13 homolog A | Often (30–79%) | In 1 condition |
| DPYDdihydropyrimidine dehydrogenase | Sometimes (5–29%) | In 1 condition |
| GRIN1glutamate ionotropic receptor NMDA type subunit 1 | Sometimes (5–29%) | In 1 condition |
| PAFAH1B1platelet activating factor acetylhydrolase 1b regulatory subunit 1 | Sometimes (5–29%) | In 1 condition |
| PCDH19protocadherin 19 | Sometimes (5–29%) | In 1 condition |
| WARS2tryptophanyl tRNA synthetase 2, mitochondrial | Sometimes (5–29%) | In 1 condition |
| CHD8chromodomain helicase DNA binding protein 8 | Rarely (1–4%) | In 1 condition |
| SMSspermine synthase | Rarely (1–4%) | In 1 condition |
| AIMP2aminoacyl tRNA synthetase complex interacting multifunctional protein 2 | Not recorded | In 1 condition |
| BUB1BBUB1 mitotic checkpoint serine/threonine kinase B | Not recorded | In 1 condition |
| CDKL5cyclin dependent kinase like 5 | Not recorded | In 1 condition |
| CRPPACDP-L-ribitol pyrophosphorylase A | Not recorded | In 1 condition |
| ERCC6ERCC excision repair 6, chromatin remodeling factor | Not recorded | In 1 condition |
| FHfumarate hydratase | Not recorded | In 1 condition |
| FKRPfukutin related protein | Not recorded | In 2 conditions |
| FKTNfukutin | Not recorded | In 1 condition |
| GUF1GTP binding elongation factor GUF1 | Not recorded | In 1 condition |
| HSPD1heat shock protein family D (Hsp60) member 1 | Not recorded | In 1 condition |
| IDSiduronate 2-sulfatase | Not recorded | In 1 condition |
| IER3IP1immediate early response 3 interacting protein 1 | Not recorded | In 1 condition |
| OCLNoccludin | Not recorded | In 1 condition |
| OFD1OFD1 centriole and centriolar satellite protein | Not recorded | In 1 condition |
| PCDH12protocadherin 12 | Not recorded | In 1 condition |
| PIGPphosphatidylinositol glycan anchor biosynthesis class P | Not recorded | In 1 condition |
| PIK3R2phosphoinositide-3-kinase regulatory subunit 2 | Not recorded | In 1 condition |
| POMGNT1protein O-linked mannose N-acetylglucosaminyltransferase 1 (beta 1,2-) | Not recorded | In 1 condition |
| POMT1protein O-mannosyltransferase 1 | Not recorded | In 1 condition |
| POMT2protein O-mannosyltransferase 2 | Not recorded | In 2 conditions |
| RAB18RAB18, member RAS oncogene family | Not recorded | In 1 condition |
| SEPSECSSep (O-phosphoserine) tRNA:Sec (selenocysteine) tRNA synthase | Not recorded | In 1 condition |
| ST3GAL3ST3 beta-galactoside alpha-2,3-sialyltransferase 3 | Not recorded | In 1 condition |
| UGP2UDP-glucose pyrophosphorylase 2 | Not recorded | In 1 condition |
| UNC80unc-80 subunit of NALCN channel complex | Not recorded | In 1 condition |
| VARS1valyl-tRNA synthetase 1 | Not recorded | In 1 condition |
| VPS53VPS53 subunit of GARP complex | Not recorded | In 1 condition |
| ZNHIT3zinc finger HIT-type containing 3 | Not recorded | In 1 condition |
How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.
Broader traits
Where this comes from
- The Human Phenotype Ontology, release 2026-09-01: the trait, its names, its definition and the genes linked to it. Find out more at hpo.jax.org.
- Data release 2026.10.16-c6eea6bf.
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