Trait
Extra thumb
Clinical name: Preaxial hand polydactyly
Supernumerary digits located at the radial side of the hand. Polydactyly (supernumerary digits) involving the thumb occurs in many distinct forms of high variability and severity. Ranging from fleshy nubbins over varying degrees of partial duplication/splitting to completely duplicated or even triplicated thumbs or preaxial (on the radial side of the hand) supernumerary digits.
Summary
- Also called
- Polydactyly affecting the thumb, Preaxial polydactyly of hands, Supernumerary thumb, thumb polydactyly
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
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Get my Genome Test60 genes linked to Extra thumb
Changes in these genes cause rare conditions in which Extra thumb 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 |
|---|---|---|
| LEF1lymphoid enhancer binding factor 1 | Always | In 1 condition |
| RAB34RAB34, member RAS oncogene family | Always | In 1 condition |
| DACT1dishevelled binding antagonist of beta catenin 1 | Very often (80–99%) | In 1 condition |
| KIF7kinesin family member 7 | Very often (80–99%) | In 1 condition |
| LMBR1limb development membrane protein 1 | Very often (80–99%) | In 2 conditions |
| SALL1spalt like transcription factor 1 | Very often (80–99%) | In 2 conditions |
| TCTN3tectonic family member 3 | Very often (80–99%) | In 2 conditions |
| CPLX1complexin 1 | Often (30–79%) | In 2 conditions |
| CTBP1C-terminal binding protein 1 | Often (30–79%) | In 2 conditions |
| EFTUD2elongation factor Tu GTP binding domain containing 2 | Often (30–79%) | In 2 conditions |
| GLI3GLI family zinc finger 3 | Often (30–79%) | In 3 conditions |
| HYLS1HYLS1 centriolar and ciliogenesis associated | Often (30–79%) | In 1 condition |
| LETM1leucine zipper and EF-hand containing transmembrane protein 1 | Often (30–79%) | In 2 conditions |
| NEK1NIMA related kinase 1 | Often (30–79%) | In 2 conditions |
| NELFAnegative elongation factor complex member A | Often (30–79%) | In 1 condition |
| NSD2nuclear receptor binding SET domain protein 2 | Often (30–79%) | In 2 conditions |
| PIGGphosphatidylinositol glycan anchor biosynthesis class G (EMM blood group) | Often (30–79%) | In 1 condition |
| SALL4spalt like transcription factor 4 | Often (30–79%) | In 3 conditions |
| B9D1B9 domain containing 1 | Sometimes (5–29%) | In 1 condition |
| B9D2B9 domain containing 2 | Sometimes (5–29%) | In 1 condition |
| BHLHA9basic helix-loop-helix family member a9 | Sometimes (5–29%) | In 1 condition |
| CC2D2Acoiled-coil and C2 domain containing 2A | Sometimes (5–29%) | In 1 condition |
| CDC45cell division cycle 45 | Sometimes (5–29%) | In 1 condition |
| CEP290centrosomal protein 290 | Sometimes (5–29%) | In 1 condition |
| CHN1chimerin 1 | Sometimes (5–29%) | In 1 condition |
| CPLANE1ciliogenesis and planar polarity effector complex subunit 1 | Sometimes (5–29%) | In 1 condition |
| CSPP1centrosome and spindle pole associated protein 1 | Sometimes (5–29%) | In 1 condition |
| DYNC2H1dynein cytoplasmic 2 heavy chain 1 | Sometimes (5–29%) | In 1 condition |
| DYNC2I1dynein 2 intermediate chain 1 | Sometimes (5–29%) | In 1 condition |
| DYNC2I2dynein 2 intermediate chain 2 | Sometimes (5–29%) | In 1 condition |
| EXTL3exostosin like glycosyltransferase 3 | Sometimes (5–29%) | In 1 condition |
| FANCD2FA complementation group D2 | Sometimes (5–29%) | In 1 condition |
| FGFR2fibroblast growth factor receptor 2 | Sometimes (5–29%) | In 1 condition |
| FGFRL1fibroblast growth factor receptor like 1 | Sometimes (5–29%) | In 1 condition |
| GJA1gap junction protein alpha 1 | Sometimes (5–29%) | In 1 condition |
| HEATR3HEAT repeat containing 3 | Sometimes (5–29%) | In 1 condition |
| HOXD13homeobox D13 | Sometimes (5–29%) | In 1 condition |
| IFT80intraflagellar transport 80 | Sometimes (5–29%) | In 1 condition |
| MAFBMAF bZIP transcription factor B | Sometimes (5–29%) | In 1 condition |
| MKS1MKS transition zone complex subunit 1 | Sometimes (5–29%) | In 1 condition |
Show 20 more genes
| Gene | How often it is seen | Conditions |
|---|---|---|
| OFD1OFD1 centriole and centriolar satellite protein | Sometimes (5–29%) | In 1 condition |
| PHF8PHD finger protein 8 | Sometimes (5–29%) | In 1 condition |
| PUF60poly(U) binding splicing factor 60 | Sometimes (5–29%) | In 1 condition |
| RPGRIP1RPGR interacting protein 1 | Sometimes (5–29%) | In 1 condition |
| RPGRIP1LRPGRIP1 like | Sometimes (5–29%) | In 1 condition |
| SMOsmoothened, frizzled class receptor | Sometimes (5–29%) | In 2 conditions |
| TCTN1tectonic family member 1 | Sometimes (5–29%) | In 1 condition |
| TCTN2tectonic family member 2 | Sometimes (5–29%) | In 1 condition |
| TFAP2Atranscription factor AP-2 alpha | Sometimes (5–29%) | In 2 conditions |
| TMEM107transmembrane protein 107 | Sometimes (5–29%) | In 1 condition |
| TMEM216transmembrane protein 216 | Sometimes (5–29%) | In 1 condition |
| TMEM231transmembrane protein 231 | Sometimes (5–29%) | In 1 condition |
| TMEM237transmembrane protein 237 | Sometimes (5–29%) | In 1 condition |
| TMEM67transmembrane protein 67 | Sometimes (5–29%) | In 1 condition |
| TXNDC15thioredoxin domain containing 15 | Sometimes (5–29%) | In 1 condition |
| WDR35WD repeat domain 35 | Sometimes (5–29%) | In 1 condition |
| ZNF699zinc finger protein 699 | Sometimes (5–29%) | In 1 condition |
| HEPACAMhepatic and glial cell adhesion molecule | Rarely (1–4%) | In 1 condition |
| PTENphosphatase and tensin homolog | Rarely (1–4%) | In 1 condition |
| GLI1GLI family zinc finger 1 | 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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