Traits

Traits linked to KMT2A

lysine methyltransferase 2A

The Human Phenotype Ontology links 102 traits to KMT2A, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of head or neck

Trait	How often it is seen
Bulbous nose	Always
Monobrow	Always
Depressed nasal tip	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
Long eyelashes	Very often (80–99%)
Thick eyebrow	Very often (80–99%)
Wide nasal bridge	Very often (80–99%)
Broad lateral eyebrow	Often (30–79%)
Broad nasal tip	Often (30–79%)
Broad opening between the eyelids	Often (30–79%)
Drooping brow	Often (30–79%)
Eversion of lateral third of lower eyelids	Often (30–79%)
Exaggerated cupid's bow	Often (30–79%)
Eye folds	Often (30–79%)
Facial asymmetry	Often (30–79%)
Failure of development of between one and six teeth	Often (30–79%)
High palate	Often (30–79%)
Highly arched eyebrow	Often (30–79%)
Little lower jaw	Often (30–79%)
Long philtrum	Often (30–79%)
Low hairline at back of neck	Often (30–79%)
Narrow eyelid opening	Often (30–79%)
Prominent forehead	Often (30–79%)
Round face	Often (30–79%)
Short columella	Often (30–79%)
Short opening between the eyelids	Often (30–79%)
Thin red part of the upper lip	Often (30–79%)
Abnormally small head	Sometimes (5–29%)
Corners of eye widely separated	Sometimes (5–29%)
Flat face	Sometimes (5–29%)
High forehead	Sometimes (5–29%)
Long, narrow head	Sometimes (5–29%)
Short nose	Sometimes (5–29%)
Webbed neck	Sometimes (5–29%)
Narrow opening between the eyelids	Not recorded
Wide nose	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Delayed speech and language development	Always
Global developmental delay	Always
Intellectual disability	Always
Aggressive behavior	Often (30–79%)
Anxiety	Often (30–79%)
Behavioral abnormality	Often (30–79%)
Delayed motor skills	Often (30–79%)
Difficulty sleeping	Often (30–79%)
Epilepsy	Often (30–79%)
Low frustration tolerance	Often (30–79%)
More active than typical	Often (30–79%)
Repetitive movements	Often (30–79%)
Short attention span	Often (30–79%)
Abnormal corpus callosum morphology	Sometimes (5–29%)
Autism	Sometimes (5–29%)
Psychomotor deterioration	Sometimes (5–29%)
Wide based walk	Not recorded

Abnormality of limbs

Trait	How often it is seen
Dropped arches	Always
Curvature of little finger	Very often (80–99%)
Abnormality of the elbow	Often (30–79%)
Contracture of the distal interphalangeal joint of the fingers	Often (30–79%)
Short 5th finger	Often (30–79%)
Tapered finger	Often (30–79%)
Webbed 2nd and 3rd toes	Often (30–79%)
Abnormality of the hand	Sometimes (5–29%)
Curvature of digit	Sometimes (5–29%)
Disproportionately short upper portion of limb	Sometimes (5–29%)
Long big toe	Sometimes (5–29%)
Small hand	Sometimes (5–29%)
Short finger bones	Not recorded
Short middle bone of finger	Not recorded
Short toe	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Advanced bone age	Often (30–79%)
Delayed bone maturation	Often (30–79%)
Low muscle tone	Often (30–79%)
Absent/small ribs	Sometimes (5–29%)
Double-Jointed	Sometimes (5–29%)
Funnel chest	Sometimes (5–29%)
Hyperextensibility at elbow	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Excessive hairiness over body	Always
Generalized hypertrichosis	Always
Prominent digit pad	Always
Hairy elbow	Very often (80–99%)
Thick hair	Very often (80–99%)
Congenital, generalized hypertrichosis	Often (30–79%)
Spinal dimple	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Constipation	Often (30–79%)
Feeding difficulties	Often (30–79%)
Poor swallowing	Often (30–79%)
Acid reflux	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Blue outer white part of eyeball	Often (30–79%)
Cross-eyed	Often (30–79%)
Wide-set eyes	Often (30–79%)
Drooping upper eyelid	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Growth delay as children	Always
Short stature	Always
Prenatal growth deficiency	Often (30–79%)
Faltering weight	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
An opening in the wall separating the top two chambers of the heart	Sometimes (5–29%)
Patent ductus arteriosus	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Sometimes (5–29%)
Recurrent middle ear infection	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Dilatation of renal calices	Sometimes (5–29%)
Undescended testes	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Decreased response to growth hormone stimulation test	Often (30–79%)

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.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to KMT2A and how often each is seen. Find out more at hpo.jax.org.

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