Traits

Traits linked to MYH7

myosin heavy chain 7

The Human Phenotype Ontology links 141 traits to MYH7, by body system: features seen in people with one of the gene's rare conditions.

MYH7

Abnormality of the cardiovascular system

Trait	How often it is seen
Enlarged and thickened heart muscle	Always
Interstitial cardiac fibrosis	Always
Left atrial enlargement	Always
Abnormal cardiovascular system morphology	Very often (80–99%)
An opening in the wall separating the top two chambers of the heart	Very often (80–99%)
Ebstein anomaly of the tricuspid valve	Very often (80–99%)
Imperforate tricuspid valve	Very often (80–99%)
Left ventricular noncompaction	Very often (80–99%)
Left ventricular systolic dysfunction	Very often (80–99%)
Reduced left ventricular ejection fraction	Very often (80–99%)
Stretched and thinned heart muscle	Very often (80–99%)
Abnormal cardiac septum morphology	Often (30–79%)
Abnormal heart rate	Often (30–79%)
Biventricular hypertrophy	Often (30–79%)
Cardiac failure	Often (30–79%)
Complete right bundle branch block	Often (30–79%)
Elevated jugular venous pressure	Often (30–79%)
Fourth heart sound	Often (30–79%)
Holosystolic murmur	Often (30–79%)
Palpitations	Often (30–79%)
Patent ductus arteriosus	Often (30–79%)
Quivering upper heart chambers resulting in irregular heartbeat	Often (30–79%)
Right axis deviation	Often (30–79%)
Tricuspid regurgitation	Often (30–79%)
Abnormal endocardium morphology	Sometimes (5–29%)
Aortic valve has two leaflets rather than three	Sometimes (5–29%)
Disruption of blood oxygen supply to brain	Sometimes (5–29%)
Increased blood pressure in blood vessels of lungs	Sometimes (5–29%)
Mitral regurgitation	Sometimes (5–29%)
Mitral valve prolapse	Sometimes (5–29%)
Narrowing of aorta	Sometimes (5–29%)
Perimembranous ventricular septal defect	Sometimes (5–29%)
Right ventricular failure	Sometimes (5–29%)
Right ventricular hypertrophy	Sometimes (5–29%)
Sinus tachycardia	Sometimes (5–29%)
Sudden cardiac death	Sometimes (5–29%)
Underdeveloped lung artery	Sometimes (5–29%)
Ventricular tachycardia	Sometimes (5–29%)
Heart attack	Rarely (1–4%)
Stroke	Rarely (1–4%)
Asymmetric septal hypertrophy	Not recorded
Narrowing of blood vessel below aortic heart valve	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
EMG: myopathic abnormalities	Always
Excessive inward curvature of lower spine	Always
Scoliosis	Always
Thoracic scoliosis	Always
Tibialis anterior muscle atrophy	Always
Muscular dystrophy	Very often (80–99%)
Axial muscle weakness	Often (30–79%)
Diffuse skeletal muscle wasting	Often (30–79%)
Generalized decreased muscle tone	Often (30–79%)
Intermittent episodes of respiratory insufficiency due to muscle weakness	Often (30–79%)
Minicore myopathy	Often (30–79%)
Multiple joint contractures	Often (30–79%)
Muscle fiber degeneration	Often (30–79%)
Muscle weakness	Often (30–79%)
Neck muscle weakness	Often (30–79%)
Poor head control	Often (30–79%)
Progressive muscle weakness	Often (30–79%)
Proximal neurogenic muscle weakness	Often (30–79%)
Reduced spine movement	Often (30–79%)
Type 1 muscle fiber predominance	Often (30–79%)
Wasting of muscles near the body	Often (30–79%)
Weakness of outermost muscles	Often (30–79%)
Abnormal formation of the hip	Sometimes (5–29%)
Difficulty running	Sometimes (5–29%)
Difficulty walking up stairs	Sometimes (5–29%)
EMG abnormality	Sometimes (5–29%)
Loss of fat tissue in localized area	Sometimes (5–29%)
Muscle tissue disease	Sometimes (5–29%)
Neck flexion weakness	Sometimes (5–29%)
Absent muscle fiber merosin	Not recorded
Centrally nucleated skeletal muscle fibers	Not recorded
EMG: neuropathic changes	Not recorded
Generalized muscle wasting	Not recorded
Generalized muscle weakness	Not recorded
Ragged-red muscle fibers	Not recorded
Rimmed vacuoles	Not recorded
Scapuloperoneal amyotrophy	Not recorded
Scapuloperoneal weakness	Not recorded

Abnormality of limbs

Trait	How often it is seen
Distal lower limb muscle weakness	Always
Weak shoulder muscles	Always
Weakness of long finger extensor muscles	Always
Foot drop	Very often (80–99%)
Toe extensor amyotrophy	Very often (80–99%)
Abnormal calf muscles	Often (30–79%)
Calf muscle pseudohypertrophy	Often (30–79%)
Increased size of calf muscles	Often (30–79%)
Limb-girdle muscle weakness	Often (30–79%)
Talipes cavus equinovarus	Often (30–79%)
Winged shoulder blade	Often (30–79%)
Dropped arches	Sometimes (5–29%)
Fluid accumulation in lower limbs	Sometimes (5–29%)
Pelvic girdle muscle weakness	Sometimes (5–29%)
Proximal lower limb muscle weakness	Sometimes (5–29%)
Shoulder girdle muscle wasting	Sometimes (5–29%)
Amyotrophy of ankle musculature	Not recorded
High-arched foot	Not recorded

Abnormality of head or neck

Trait	How often it is seen
High palate	Often (30–79%)
Limited neck flexibility	Often (30–79%)
Myopathic facies	Often (30–79%)
Weakness of facial musculature	Often (30–79%)
Weakness of orbicularis oculi muscle	Often (30–79%)
Big lower jaw	Sometimes (5–29%)
Small retruded chin	Sometimes (5–29%)
Bell's palsy	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Decreased reflex response	Always
Toe walking	Always
Abnormal gait	Often (30–79%)
Delayed motor skills	Often (30–79%)
High pitched voice	Often (30–79%)
Loss of ability to walk	Often (30–79%)
Falls	Sometimes (5–29%)
Waddling gait	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory function loss	Very often (80–99%)
Exertional breathlessness	Often (30–79%)
Nocturnal hypoventilation	Often (30–79%)
Orthopnea	Often (30–79%)
Stiff lung or chest wall causing decreased lung volume	Often (30–79%)
Breathing difficulty	Sometimes (5–29%)
Low blood oxygen level	Sometimes (5–29%)
Reduced vital capacity	Sometimes (5–29%)

Constitutional symptom

Trait	How often it is seen
Fatigue	Very often (80–99%)
Chest pain	Often (30–79%)
Muscle ache	Often (30–79%)
Sudden death	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Fluid retention	Often (30–79%)
Increased muscle lipid content	Often (30–79%)
Mildly elevated creatine kinase	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Blood clot in artery	Sometimes (5–29%)
Pulmonary thromboembolism	Sometimes (5–29%)
Thromboembolic stroke	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Muscle fiber hyaline bodies	Always
Abnormal mitochondria in muscle tissue	Often (30–79%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Premature birth	Very often (80–99%)
Only one artery in umbilical cord instead of two	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Short stature	Always
Faltering weight	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Blue discoloration of the skin	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 MYH7 and how often each is seen. Find out more at hpo.jax.org.

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