Traits

Traits linked to MYMK

myomaker, myoblast fusion factor

The Human Phenotype Ontology links 74 traits to MYMK, by body system: features seen in people with one of the gene's rare conditions.

MYMK

Abnormality of head or neck

Trait	How often it is seen
Bell's palsy	Always
Broad nasal tip	Always
Eyelids stay open	Always
Little lower jaw	Always
Nasal tip, upturned	Always
Receding chin	Always
Weakness of facial musculature	Always
Aplasia/Hypoplasia of the tongue	Very often (80–99%)
Decreased volume of lip	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
Eye folds	Very often (80–99%)
Long philtrum	Very often (80–99%)
Pierre-Robin sequence	Very often (80–99%)
Short nose	Very often (80–99%)
Abnormally small head	Often (30–79%)
Abnormally small tongue	Often (30–79%)
Cleft palate	Often (30–79%)
High palate	Often (30–79%)
Retraction of the tongue	Often (30–79%)
Asymmetry of the posterior head	Not recorded
Big calvaria	Not recorded
Decrease in jaw mobility	Not recorded
Depressed nasal bridge	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle tissue disease	Always
Poorly developed skeletal musculature	Always
Proximal neurogenic muscle weakness	Always
Reduced spine movement	Always
Weakness of outermost muscles	Always
Low muscle tone	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Scoliosis	Often (30–79%)
Abnormal deposits of calcium in the brain	Sometimes (5–29%)
Flexed joint that cannot be straightened	Not recorded
Generalized decreased muscle tone	Not recorded
Severely decreased muscle tone	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Epilepsy	Always
Motor delay	Always
Cranial nerve paralysis	Often (30–79%)
Intellectual disability	Often (30–79%)
Absent/small cerebellum	Sometimes (5–29%)
Global developmental delay	Sometimes (5–29%)
Ventriculomegaly	Sometimes (5–29%)
Small brainstem	Not recorded

Abnormality of limbs

Trait	How often it is seen
Short fingers or toes	Very often (80–99%)
Club feet	Often (30–79%)
Small pec muscle	Often (30–79%)
Aplasia of the pectoralis major muscle	Sometimes (5–29%)
Finger bends toward pinky	Sometimes (5–29%)
Tapered finger	Not recorded

Abnormality of the eye

Trait	How often it is seen
Clouding of the lens of the eye	Always
Glaucoma	Always
Drooping upper eyelid	Very often (80–99%)
Impaired ocular abduction	Very often (80–99%)
Eye muscle paralysis	Not recorded
Oculomotor nerve palsy	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Bowel irritability	Always
Poor swallowing	Always
Feeding difficulties	Very often (80–99%)
Acid reflux	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Hypertensive crisis	Sometimes (5–29%)
Increased blood pressure in blood vessels of lungs	Sometimes (5–29%)
Abnormal cardiac septum morphology	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Undescended testes	Always
Glanular hypospadias	Sometimes (5–29%)
Hydronephrosis	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Abnormality of the larynx	Sometimes (5–29%)
Laryngeal stenosis	Sometimes (5–29%)
Respiratory function loss	Not recorded

Growth abnormality

Trait	How often it is seen
Growth delay	Very often (80–99%)
Short stature	Often (30–79%)
Faltering weight	Not recorded

Abnormality of prenatal development or birth

Trait	How often it is seen
Less than 10 fetal movements in 12 hours	Not recorded

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Always

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	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 MYMK and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test