Traits

Traits linked to SDHA

succinate dehydrogenase complex flavoprotein subunit A

The Human Phenotype Ontology links 190 traits to SDHA, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Global developmental delay	Always
Headache	Always
Inability to coordinate movements when walking	Always
Instability or lack of coordination of central trunk muscles	Always
Loss of developmental milestones	Always
Unsteady walk	Always
Abnormal gait	Often (30–79%)
Ataxia	Often (30–79%)
Babinski sign	Often (30–79%)
Balance impairment	Often (30–79%)
Brisk knee jerk	Often (30–79%)
Clumsiness	Often (30–79%)
Cranial nerve paralysis	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Depression	Often (30–79%)
Dysesthesia	Often (30–79%)
Episodic paroxysmal anxiety	Often (30–79%)
Generalized myoclonic seizure	Often (30–79%)
Hyperactive deep tendon reflexes	Often (30–79%)
Limb ataxia	Often (30–79%)
Motor delay	Often (30–79%)
Progressive degeneration of movement	Often (30–79%)
Progressive psychomotor deterioration	Often (30–79%)
Recurrent paroxysmal headache	Often (30–79%)
Upper limb hyperreflexia	Often (30–79%)
Communication delay	Sometimes (5–29%)
Cranial nerve compression	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Focal myoclonic seizure	Sometimes (5–29%)
Inability to move vocal cords	Sometimes (5–29%)
Irritability	Sometimes (5–29%)
Moderate global developmental delay	Sometimes (5–29%)
Panic attack	Sometimes (5–29%)
Tremor	Sometimes (5–29%)
Dementia	Rarely (1–4%)
Loss of ability to walk	Rarely (1–4%)
Cognitive impairment	Not recorded
Dystonia	Not recorded
Increased reflexes	Not recorded
Jerking	Not recorded
Leukoencephalopathy	Not recorded
Progressive leukoencephalopathy	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Disease of the heart muscle	Always
Enlarged heart	Always
Reduced left ventricular ejection fraction	Always
Stretched and thinned heart muscle	Always
Left ventricular systolic dysfunction	Very often (80–99%)
Abnormal heart rate	Often (30–79%)
Abnormal left ventricular function	Often (30–79%)
Abnormality of the cardiovascular system	Often (30–79%)
Cardiac failure	Often (30–79%)
Decrease in blood pressure upon standing up	Often (30–79%)
Elevated heart rate	Often (30–79%)
Enlarged and thickened heart muscle	Often (30–79%)
Fainting spell	Often (30–79%)
High blood pressure	Often (30–79%)
Hypertension associated with pheochromocytoma	Often (30–79%)
Hypertensive retinopathy	Often (30–79%)
Left ventricular hypertrophy	Often (30–79%)
Left ventricular noncompaction	Often (30–79%)
Palpitations	Often (30–79%)
Positive regitine blocking test	Often (30–79%)
Sinus tachycardia	Often (30–79%)
Swollen lymph nodes in center of chest	Often (30–79%)
Abnormal atrioventricular conduction	Sometimes (5–29%)
Arachnoid hemangiomatosis	Sometimes (5–29%)
Cardiogenic shock	Sometimes (5–29%)
Hypertensive crisis	Sometimes (5–29%)
Inflammation of heart muscle	Sometimes (5–29%)
Noncompaction cardiomyopathy	Sometimes (5–29%)
Swollen lymph nodes	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Abdominal pain	Very often (80–99%)
Diarrhea	Very often (80–99%)
Gastrointestinal stroma tumor	Very often (80–99%)
Nausea and vomiting	Very often (80–99%)
Stomach tumor	Very often (80–99%)
Accumulation of fluid in the abdomen	Often (30–79%)
Constipation	Often (30–79%)
Intermittent abdominal pain	Often (30–79%)
Intestinal obstruction	Often (30–79%)
Nausea	Often (30–79%)
Poor swallowing	Often (30–79%)
Abdominal mass	Sometimes (5–29%)
Abnormality of the liver	Sometimes (5–29%)
Anorexia	Sometimes (5–29%)
Colon tumor	Sometimes (5–29%)
Esophageal tumor	Sometimes (5–29%)
Feeding difficulties in infancy	Sometimes (5–29%)
Gastrointestinal tract tumor	Sometimes (5–29%)
Rectal tumor	Sometimes (5–29%)
Small intestine tumor	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Distal muscle wasting	Often (30–79%)
Generalized muscle weakness	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Proximal neurogenic muscle weakness	Often (30–79%)
Skeletal myopathy	Often (30–79%)
Tired easily	Often (30–79%)
EMG abnormality	Sometimes (5–29%)
Frequent falls	Sometimes (5–29%)
Generalized decreased muscle tone	Sometimes (5–29%)
Loss of fat tissue in localized area	Sometimes (5–29%)
Muscle degeneration	Sometimes (5–29%)
Muscle tissue disease	Sometimes (5–29%)
Spastic paraparesis	Sometimes (5–29%)
Spastic tetraparesis	Sometimes (5–29%)
Poor head control	Rarely (1–4%)
Flexed joint that cannot be straightened	Not recorded
Low muscle tone, in neonatal onset	Not recorded
Muscle weakness	Not recorded
Ragged-red muscle fibers	Not recorded

Laboratory abnormality

Trait	How often it is seen
3-Methylglutaconic aciduria	Always
Elevated lactate:pyruvate ratio	Always
Higher than normal levels of lactate in blood	Always
Increased hepatic glycogen content	Always
Elevated urinary dopamine	Often (30–79%)
Elevated urinary epinephrine level	Often (30–79%)
Elevated urinary norepinephrine level	Often (30–79%)
Fluid retention	Often (30–79%)
High blood calcium levels	Often (30–79%)
High urine protein levels	Often (30–79%)
Blood in urine	Sometimes (5–29%)
Elevated calcitonin	Sometimes (5–29%)
High blood sugar	Sometimes (5–29%)
Increased intramyocellular lipid droplets	Not recorded
Stress/infection-induced lactic acidosis	Not recorded

Abnormality of the eye

Trait	How often it is seen
Double vision	Always
Loss of peripheral vision	Always
Optic atrophy	Always
Visual impairment	Always
Abnormality of the eye	Often (30–79%)
Decreased clarity of vision	Often (30–79%)
Gaze-evoked nystagmus	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Absent iris	Rarely (1–4%)
Blindness	Rarely (1–4%)
Paralysis or weakness of muscles within or surrounding outer part of eye	Rarely (1–4%)
Pigmentary retinopathy	Rarely (1–4%)
Drooping upper eyelid	Not recorded
Eye muscle paralysis	Not recorded

Abnormality of the ear

Trait	How often it is seen
Dizziness	Always
Hearing impairment	Often (30–79%)
Paroxysmal vertigo	Often (30–79%)
Pulsatile tinnitus	Often (30–79%)
Ringing in ears	Often (30–79%)
Conductive deafness	Sometimes (5–29%)
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Paraganglioma	Always
Adrenal pheochromocytoma	Very often (80–99%)
Extraadrenal pheochromocytoma	Very often (80–99%)
Pheochromocytoma	Very often (80–99%)
Adrenal overactivity	Often (30–79%)
Adrenocortical adenoma	Often (30–79%)
Paraganglioma of head and neck	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Proportionate short stature	Often (30–79%)
Severe short stature	Often (30–79%)
Weight loss	Often (30–79%)
Prenatal growth deficiency	Sometimes (5–29%)
Short stature	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Gastrointestinal bleeding	Very often (80–99%)
Bleeding in brain	Often (30–79%)
Low number of red blood cells or hemoglobin	Sometimes (5–29%)
Thromboembolic stroke	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Glomerular sclerosis	Often (30–79%)
Cancer starting in small tubes in kidneys	Sometimes (5–29%)
Renal failure	Sometimes (5–29%)
Vesicoureteral reflux	Rarely (1–4%)

Abnormality of the integument

Trait	How often it is seen
Flushing	Often (30–79%)
Sporadic excessive sweating	Often (30–79%)
Irregular hyperpigmentation	Sometimes (5–29%)
Paleness	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Breathing difficulties	Very often (80–99%)
Exertional breathlessness	Often (30–79%)
Lung infiltrates	Often (30–79%)
Orthopnea	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Fatigue	Very often (80–99%)
Chest pain	Often (30–79%)
Muscle ache	Often (30–79%)
Decreased ability to exercise	Not recorded

Abnormality of limbs

Trait	How often it is seen
Limb muscle weakness	Always
Inability to straighten knee	Sometimes (5–29%)
Lower limb hypertonia	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased activity of mitochondrial complex II	Always
Abnormal mitochondria in muscle tissue	Not recorded

Abnormal tissue mass

Trait	How often it is seen
Cancer of connective tissue	Very often (80–99%)
Leiomyosarcoma	Very often (80–99%)

Abnormality of head or neck

Trait	How often it is seen
Mild microcephaly	Sometimes (5–29%)
Retinal capillary hemangioma	Sometimes (5–29%)

Abnormality of the voice

Trait	How often it is seen
Inability to produce voice sounds	Often (30–79%)
Loss of voice	Often (30–79%)

Abnormality of the immune system

Trait	How often it is seen
Skin rash	Sometimes (5–29%)

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 SDHA and how often each is seen. Find out more at hpo.jax.org.

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