Trait
Decreased muscle tone in infant
Clinical name: Floppy infant
Floppiness/hypotonia is defined as reduced resistance to passive movement of joints. Physical examination of floppy/hypotonic infants shows head lag, lack of shoulder and elbow muscle contraction on traction response, inability to tighten the shoulder girdle muscles (or slipping through) when held under the axillae, scarf sign (when the arm is pulled to the opposite side, the arm wraps around the neck with the elbow crossing midline), hyperdorsiflexion of the feet, easy apposition of the thumb against the forearm, feet touching the cheek with ease and without discomfort, frog leg position, and inverted U sign on ventral suspension (head, arms, and legs hanging down without elbow or knee flexion and the trunk rounded in a dome shape).
Summary
- Also called
- Hypotonia early, Hypotonia in infancy, Hypotonia, early, Infantile hypotonia, Infantile muscular hypotonia
- Body system
- Abnormality of the musculoskeletal system
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
Read the genes linked to Decreased muscle tone in infant, and the rest of your genome, with one test.
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Get my Genome Test205 genes linked to Decreased muscle tone in infant
Changes in these genes cause rare conditions in which Decreased muscle tone in infant 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 |
|---|---|---|
| COG8component of oligomeric golgi complex 8 | Always | In 2 conditions |
| DSTdystonin | Always | In 1 condition |
| KDM6Blysine demethylase 6B | Always | In 1 condition |
| MDGA2MAM domain containing glycosylphosphatidylinositol anchor 2 | Always | In 1 condition |
| MECP2methyl-CpG binding protein 2 | Always | In 2 conditions |
| PIGQphosphatidylinositol glycan anchor biosynthesis class Q | Always | In 2 conditions |
| SIAH1siah E3 ubiquitin protein ligase 1 | Always | In 1 condition |
| SUCLG1succinate-CoA ligase GDP/ADP-forming subunit alpha | Always | In 2 conditions |
| ALG11ALG11 alpha-1,2-mannosyltransferase | Very often (80–99%) | In 1 condition |
| ASXL3ASXL transcriptional regulator 3 | Very often (80–99%) | In 1 condition |
| ATP6V0A2ATPase H+ transporting V0 subunit a2 | Very often (80–99%) | In 2 conditions |
| 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 |
| B4GALT1beta-1,4-galactosyltransferase 1 | Very often (80–99%) | In 1 condition |
| COG5component of oligomeric golgi complex 5 | Very often (80–99%) | In 1 condition |
| DCHS1dachsous cadherin-related 1 | Very often (80–99%) | In 1 condition |
| DPM1dolichyl-phosphate mannosyltransferase subunit 1, catalytic | Very often (80–99%) | In 1 condition |
| ERMARDER membrane associated RNA degradation | Very often (80–99%) | In 1 condition |
| FAT4FAT atypical cadherin 4 | Very often (80–99%) | In 1 condition |
| FKRPfukutin related protein | Very often (80–99%) | In 1 condition |
| GAAalpha glucosidase | Very often (80–99%) | In 1 condition |
| GLB1galactosidase beta 1 | Very often (80–99%) | In 1 condition |
| GMPPBGDP-mannose pyrophosphorylase B | Very often (80–99%) | In 1 condition |
| IARS2isoleucyl-tRNA synthetase 2, mitochondrial | Very often (80–99%) | In 1 condition |
| LARGE1LARGE xylosyl- and glucuronyltransferase 1 | Very often (80–99%) | In 1 condition |
| MAGEL2MAGE family member L2 | Very often (80–99%) | In 1 condition |
| MAN1B1mannosidase alpha class 1B member 1 | Very often (80–99%) | In 1 condition |
| NACC1nucleus accumbens associated 1 | Very often (80–99%) | In 1 condition |
| NTNG2netrin G2 | Very often (80–99%) | In 1 condition |
| PGAP2post-GPI attachment to proteins 2 | Very often (80–99%) | In 1 condition |
| PGAP3post-GPI attachment to proteins phospholipase 3 | Very often (80–99%) | In 1 condition |
| PIGLphosphatidylinositol glycan anchor biosynthesis class L | Very often (80–99%) | In 1 condition |
| PIGOphosphatidylinositol glycan anchor biosynthesis class O | Very often (80–99%) | In 1 condition |
| PIGVphosphatidylinositol glycan anchor biosynthesis class V | Very often (80–99%) | In 1 condition |
| PIGWphosphatidylinositol glycan anchor biosynthesis class W | Very often (80–99%) | In 1 condition |
| PIGYphosphatidylinositol glycan anchor biosynthesis class Y | Very often (80–99%) | In 1 condition |
| POMT1protein O-mannosyltransferase 1 | Very often (80–99%) | In 1 condition |
| POMT2protein O-mannosyltransferase 2 | Very often (80–99%) | In 1 condition |
| PRMT7protein arginine methyltransferase 7 | Very often (80–99%) | In 1 condition |
| RAI1retinoic acid induced 1 | Very often (80–99%) | In 1 condition |
Show 165 more genes
| Gene | How often it is seen | Conditions |
|---|---|---|
| SIM1SIM bHLH transcription factor 1 | Very often (80–99%) | In 1 condition |
| SLC35A2solute carrier family 35 member A2 | Very often (80–99%) | In 1 condition |
| SYT1synaptotagmin 1 | Very often (80–99%) | In 1 condition |
| UGT1A1UDP glucuronosyltransferase family 1 member A1 | Very often (80–99%) | In 1 condition |
| WARS2tryptophanyl tRNA synthetase 2, mitochondrial | Very often (80–99%) | In 1 condition |
| AASSaminoadipate-semialdehyde synthase | Often (30–79%) | In 1 condition |
| ACADSacyl-CoA dehydrogenase short chain | Often (30–79%) | In 1 condition |
| ADARadenosine deaminase RNA specific | Often (30–79%) | In 1 condition |
| ADAT3adenosine deaminase tRNA specific 3 | Often (30–79%) | In 1 condition |
| ADGRG1adhesion G protein-coupled receptor G1 | Often (30–79%) | In 1 condition |
| ADNPactivity dependent neuroprotector homeobox | Often (30–79%) | In 1 condition |
| AFG2AAAA ATPase AFG2A | Often (30–79%) | In 1 condition |
| AHCYadenosylhomocysteinase | Often (30–79%) | In 1 condition |
| ARID1AAT-rich interaction domain 1A | Often (30–79%) | In 1 condition |
| ARID1BAT-rich interaction domain 1B | Often (30–79%) | In 1 condition |
| ARID2AT-rich interaction domain 2 | Often (30–79%) | In 1 condition |
| ARXaristaless related homeobox | Often (30–79%) | In 1 condition |
| ASAH1N-acylsphingosine amidohydrolase 1 | Often (30–79%) | In 1 condition |
| ATP10AATPase phospholipid transporting 10A (putative) | Often (30–79%) | In 1 condition |
| ATP6V1B2ATPase H+ transporting V1 subunit B2 | Often (30–79%) | In 2 conditions |
| CACNA1Ecalcium voltage-gated channel subunit alpha1 E | Often (30–79%) | In 1 condition |
| CASKcalcium/calmodulin dependent serine protein kinase | Often (30–79%) | In 2 conditions |
| CDKL5cyclin dependent kinase like 5 | Often (30–79%) | In 1 condition |
| CDONcell adhesion associated, oncogene regulated | Often (30–79%) | In 4 conditions |
| CPEcarboxypeptidase E | Often (30–79%) | In 1 condition |
| CRIPTOcripto, EGF-CFC family member | Often (30–79%) | In 4 conditions |
| CWF19L1CWF19 like cell cycle control factor 1 | Often (30–79%) | In 1 condition |
| DAG1dystroglycan 1 | Often (30–79%) | In 1 condition |
| DEAF1DEAF1 transcription factor | Often (30–79%) | In 1 condition |
| DISP1dispatched RND transporter family member 1 | Often (30–79%) | In 4 conditions |
| DLL1delta like canonical Notch ligand 1 | Often (30–79%) | In 4 conditions |
| DMXL2Dmx like 2 | Often (30–79%) | In 1 condition |
| DNMT3ADNA methyltransferase 3 alpha | Often (30–79%) | In 1 condition |
| DPAGT1dolichyl-phosphate N-acetylglucosaminephosphotransferase 1 | Often (30–79%) | In 1 condition |
| DPF2double PHD fingers 2 | Often (30–79%) | In 1 condition |
| DPYDdihydropyrimidine dehydrogenase | Often (30–79%) | In 1 condition |
| EBF3EBF transcription factor 3 | Often (30–79%) | In 2 conditions |
| FGF8fibroblast growth factor 8 | Often (30–79%) | In 4 conditions |
| FGFR1fibroblast growth factor receptor 1 | Often (30–79%) | In 2 conditions |
| FGFR3fibroblast growth factor receptor 3 | Often (30–79%) | In 2 conditions |
| FOXH1forkhead box H1 | Often (30–79%) | In 4 conditions |
| GAS1growth arrest specific 1 | Often (30–79%) | In 4 conditions |
| GATAD2BGATA zinc finger domain containing 2B | Often (30–79%) | In 1 condition |
| GLI2GLI family zinc finger 2 | Often (30–79%) | In 4 conditions |
| GLYCTKglycerate kinase | Often (30–79%) | In 1 condition |
| GNAO1G protein subunit alpha o1 | Often (30–79%) | In 1 condition |
| GRIN1glutamate ionotropic receptor NMDA type subunit 1 | Often (30–79%) | In 1 condition |
| GRIN2Aglutamate ionotropic receptor NMDA type subunit 2A | Often (30–79%) | In 1 condition |
| GRM7glutamate metabotropic receptor 7 | Often (30–79%) | In 1 condition |
| GTPBP3GTP binding protein 3, mitochondrial | Often (30–79%) | In 1 condition |
| ITCHitchy E3 ubiquitin protein ligase | Often (30–79%) | In 1 condition |
| KCNA1potassium voltage-gated channel subfamily A member 1 | Often (30–79%) | In 1 condition |
| KDM6Alysine demethylase 6A | Often (30–79%) | In 1 condition |
| KMT2Dlysine methyltransferase 2D | Often (30–79%) | In 1 condition |
| LGI1leucine rich glioma inactivated 1 | Often (30–79%) | In 1 condition |
| LRP5LDL receptor related protein 5 | Often (30–79%) | In 1 condition |
| MAFMAF bZIP transcription factor | Often (30–79%) | In 1 condition |
| MED12mediator complex subunit 12 | Often (30–79%) | In 1 condition |
| MOGSmannosyl-oligosaccharide glucosidase | Often (30–79%) | In 1 condition |
| MPDU1mannose-P-dolichol utilization defect 1 | Often (30–79%) | In 1 condition |
| MT-ATP6mitochondrially encoded ATP synthase membrane subunit 6 | Often (30–79%) | In 2 conditions |
| MT-ND1mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 1 | Often (30–79%) | In 1 condition |
| MT-ND2mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 2 | Often (30–79%) | In 1 condition |
| MT-ND3mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 3 | Often (30–79%) | In 1 condition |
| MT-ND4mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4 | Often (30–79%) | In 1 condition |
| MT-ND5mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 5 | Often (30–79%) | In 1 condition |
| MT-ND6mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 6 | Often (30–79%) | In 1 condition |
| MT-TKmitochondrially encoded tRNA-Lys (AAA/G) | Often (30–79%) | In 1 condition |
| MT-TL1mitochondrially encoded tRNA-Leu (UUA/G) 1 | Often (30–79%) | In 2 conditions |
| MT-TVmitochondrially encoded tRNA-Val (GUN) | Often (30–79%) | In 1 condition |
| MT-TWmitochondrially encoded tRNA-Trp (UGA/G) | Often (30–79%) | In 1 condition |
| MYT1Lmyelin transcription factor 1 like | Often (30–79%) | In 1 condition |
| NAGSN-acetylglutamate synthase | Often (30–79%) | In 1 condition |
| NEU1neuraminidase 1 | Often (30–79%) | In 1 condition |
| NEUROD2neuronal differentiation 2 | Often (30–79%) | In 1 condition |
| NKX2-1NK2 homeobox 1 | Often (30–79%) | In 1 condition |
| NODALnodal growth differentiation factor | Often (30–79%) | In 4 conditions |
| NUP54nucleoporin 54 | Often (30–79%) | In 1 condition |
| NUP62nucleoporin 62 | Often (30–79%) | In 1 condition |
| OCA2OCA2 melanosomal transmembrane protein | Often (30–79%) | In 1 condition |
| PACS1phosphofurin acidic cluster sorting protein 1 | Often (30–79%) | In 1 condition |
| PI4KAphosphatidylinositol 4-kinase alpha | Often (30–79%) | In 1 condition |
| PIGPphosphatidylinositol glycan anchor biosynthesis class P | Often (30–79%) | In 1 condition |
| PLCH1phospholipase C eta 1 | Often (30–79%) | In 1 condition |
| PNKPpolynucleotide kinase 3'-phosphatase | Often (30–79%) | In 1 condition |
| POGZpogo transposable element derived with ZNF domain | Often (30–79%) | In 1 condition |
| PTCH1patched 1 | Often (30–79%) | In 4 conditions |
| RAC1Rac family small GTPase 1 | Often (30–79%) | In 1 condition |
| RHOBTB2Rho related BTB domain containing 2 | Often (30–79%) | In 1 condition |
| RPL10ribosomal protein L10 | Often (30–79%) | In 1 condition |
| SATB2SATB homeobox 2 | Often (30–79%) | In 1 condition |
| SCN1Bsodium voltage-gated channel beta subunit 1 | Often (30–79%) | In 2 conditions |
| SCN2Asodium voltage-gated channel alpha subunit 2 | Often (30–79%) | In 2 conditions |
| SHHsonic hedgehog signaling molecule | Often (30–79%) | In 4 conditions |
| SIK1salt inducible kinase 1 | Often (30–79%) | In 1 condition |
| SIX3SIX homeobox 3 | Often (30–79%) | In 4 conditions |
| SLC25A22solute carrier family 25 member 22 | Often (30–79%) | In 1 condition |
| SLC32A1solute carrier family 32 member 1 | Often (30–79%) | In 1 condition |
| SLC7A7solute carrier family 7 member 7 | Often (30–79%) | In 1 condition |
| SMARCA4SWI/SNF related BAF chromatin remodeling complex subunit ATPase 4 | Often (30–79%) | In 1 condition |
| SMARCB1SWI/SNF related BAF chromatin remodeling complex subunit B1 | Often (30–79%) | In 1 condition |
| SMARCC2SWI/SNF related BAF chromatin remodeling complex subunit C2 | Often (30–79%) | In 1 condition |
| SMARCD1SWI/SNF related BAF chromatin remodeling complex subunit D1 | Often (30–79%) | In 1 condition |
| SMARCE1SWI/SNF related BAF chromatin remodeling complex subunit E1 | Often (30–79%) | In 1 condition |
| SMC1Astructural maintenance of chromosomes 1A | Often (30–79%) | In 1 condition |
| SMSspermine synthase | Often (30–79%) | In 1 condition |
| SNRPNsmall nuclear ribonucleoprotein polypeptide N | Often (30–79%) | In 1 condition |
| SONSON DNA and RNA binding protein | Often (30–79%) | In 1 condition |
| SOX11SRY-box transcription factor 11 | Often (30–79%) | In 1 condition |
| SOX4SRY-box transcription factor 4 | Often (30–79%) | In 1 condition |
| SRD5A3steroid 5 alpha-reductase 3 | Often (30–79%) | In 1 condition |
| SRPX2sushi repeat containing protein X-linked 2 | Often (30–79%) | In 1 condition |
| STAG2STAG2 cohesin complex component | Often (30–79%) | In 2 conditions |
| STILSTIL centriolar assembly protein | Often (30–79%) | In 4 conditions |
| TBC1D24TBC1 domain family member 24 | Often (30–79%) | In 1 condition |
| TBCDtubulin folding cofactor D | Often (30–79%) | In 1 condition |
| TELO2telomere maintenance 2 | Often (30–79%) | In 1 condition |
| TGIF1TGFB induced factor homeobox 1 | Often (30–79%) | In 4 conditions |
| TNNT1troponin T1, slow skeletal type | Often (30–79%) | In 1 condition |
| TRIM8tripartite motif containing 8 | Often (30–79%) | In 1 condition |
| UBA1ubiquitin like modifier activating enzyme 1 | Often (30–79%) | In 1 condition |
| UBE3Aubiquitin protein ligase E3A | Often (30–79%) | In 4 conditions |
| USP9Xubiquitin specific peptidase 9 X-linked | Often (30–79%) | In 1 condition |
| ZEB2zinc finger E-box binding homeobox 2 | Often (30–79%) | In 2 conditions |
| ZIC2Zic family zinc finger 2 | Often (30–79%) | In 4 conditions |
| CDC42cell division cycle 42 | Sometimes (5–29%) | In 1 condition |
| CLCN4Cl-/H+ antiporter 4 | Sometimes (5–29%) | In 1 condition |
| CLTCL1clathrin heavy chain like 1 | Sometimes (5–29%) | In 1 condition |
| DLK1delta like non-canonical Notch ligand 1 | Sometimes (5–29%) | In 1 condition |
| DOLKdolichol kinase | Sometimes (5–29%) | In 1 condition |
| GABRA1gamma-aminobutyric acid type A receptor subunit alpha1 | Sometimes (5–29%) | In 1 condition |
| GABRG2gamma-aminobutyric acid type A receptor subunit gamma2 | Sometimes (5–29%) | In 1 condition |
| GNB1G protein subunit beta 1 | Sometimes (5–29%) | In 1 condition |
| H19H19 imprinted maternally expressed transcript | Sometimes (5–29%) | In 1 condition |
| H4C5H4 clustered histone 5 | Sometimes (5–29%) | In 1 condition |
| IGF2insulin like growth factor 2 | Sometimes (5–29%) | In 1 condition |
| KCNH1potassium voltage-gated channel subfamily H member 1 | Sometimes (5–29%) | In 1 condition |
| KCNJ11potassium inwardly rectifying channel subfamily J member 11 | Sometimes (5–29%) | In 1 condition |
| KCNN3potassium calcium-activated channel subfamily N member 3 | Sometimes (5–29%) | In 1 condition |
| KIF15kinesin family member 15 | Sometimes (5–29%) | In 1 condition |
| MEG3maternally expressed 3 | Sometimes (5–29%) | In 1 condition |
| MTRFRmitochondrial translation release factor in rescue | Sometimes (5–29%) | In 1 condition |
| NEK1NIMA related kinase 1 | Sometimes (5–29%) | In 1 condition |
| OPLAH5-oxoprolinase, ATP-hydrolysing | Sometimes (5–29%) | In 1 condition |
| PCDH19protocadherin 19 | Sometimes (5–29%) | In 1 condition |
| PPP2R5Cprotein phosphatase 2 regulatory subunit B'gamma | Sometimes (5–29%) | In 1 condition |
| PRDM5PR/SET domain 5 | Sometimes (5–29%) | In 1 condition |
| RTL1retrotransposon Gag like 1 | Sometimes (5–29%) | In 1 condition |
| SARDHsarcosine dehydrogenase | Sometimes (5–29%) | In 1 condition |
| SCN1Asodium voltage-gated channel alpha subunit 1 | Sometimes (5–29%) | In 1 condition |
| SCN9Asodium voltage-gated channel alpha subunit 9 | Sometimes (5–29%) | In 1 condition |
| SLC19A3solute carrier family 19 member 3 | Sometimes (5–29%) | In 1 condition |
| TRAPPC11trafficking protein particle complex subunit 11 | Sometimes (5–29%) | In 2 conditions |
| TUBB2Btubulin beta 2B class IIb | Sometimes (5–29%) | In 1 condition |
| UBTFupstream binding transcription factor | Sometimes (5–29%) | In 1 condition |
| WDR83OSWD repeat domain 83 opposite strand | Sometimes (5–29%) | In 1 condition |
| ZNF469zinc finger protein 469 | Sometimes (5–29%) | In 1 condition |
| ACADVLacyl-CoA dehydrogenase very long chain | Rarely (1–4%) | In 1 condition |
| BMP2bone morphogenetic protein 2 | Rarely (1–4%) | In 1 condition |
| ATRXATRX chromatin remodeler | Not recorded | In 2 conditions |
| COL5A1collagen type V alpha 1 chain | Not recorded | In 1 condition |
| GAMTguanidinoacetate N-methyltransferase | Not recorded | In 1 condition |
| PEX13peroxisomal biogenesis factor 13 | Not recorded | In 1 condition |
| SUOXsulfite oxidase | Not recorded | In 1 condition |
| TRPS1transcriptional repressor GATA binding 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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