What Causes Primary Orthostatic Tremor, and Is It Hereditary?

The exact biological cause of primary orthostatic tremor (POT) is not yet fully established ^[1]. Research suggests that POT stems from an issue in how different parts of the brain communicate with each other, rather than a single structural injury or defect. Most importantly, POT is overwhelmingly considered a sporadic condition, meaning it usually occurs randomly in an individual rather than being directly passed down from parent to child ^[2].

What is “Primary” Orthostatic Tremor?

To understand the cause, it helps to understand the diagnosis. The term “primary” generally means that no other underlying neurological disease has been identified as the cause of the tremor ^[3]. The “classic” syndrome is defined by two key pieces of information:

1. A clinical pattern of unsteadiness and fast tremor that is most prominent when standing and goes away or improves when sitting or walking ^[4].
2. A confirmation using surface electromyography (EMG)—a test that measures muscle electrical activity—showing a highly synchronous, regular tremor in the weight-bearing leg muscles between 13 and 18 Hz (cycles per second) ^[5].

An EMG frequency alone does not establish a diagnosis; a clinician must evaluate your overall clinical pattern to distinguish POT from other movement disorders, medication side effects, or secondary causes ^[6].

What is happening in the brain?

While the exact origin of the tremor remains unknown, researchers believe POT is driven by abnormal, rhythmic electrical signals in the brain—often referred to as a central oscillator (a repeating rhythm generated within the brain’s movement-control networks) ^[1].

Current evidence points to a central motor-network issue involving several brain regions that coordinate movement, posture, and balance, such as the cerebellum, the brainstem, the thalamus, and the motor cortex ^[7]. Abnormal rhythmic activity and synchronization have been detected in these networks in people with POT ^[8]. However, it is important to understand that these network models are currently medical hypotheses under investigation, rather than proven explanations for exactly where or why the tremor begins ^[9].

Can I pass this on to my children?

Worrying about whether you can pass a condition to your children is very common, and uncertainty about a condition’s cause can be stressful. For the vast majority of people, classic POT is sporadic, and most patients do not need family screening ^[2][10].

Currently, no validated parent-to-child risk percentage is known, and no established inheritance pattern has been found ^[2]. In one large study of 184 people with POT, about 4.9% reported having a family member with the same condition ^[2]. However, this statistic simply reflects self-reported family history; it is not an estimate of a child’s risk, and it does not prove that a specific gene is being passed down. There is no known single “POT gene” that directly causes the classic form of this disorder ^[6].

Is there a genetic test for POT?

Because there is no known genetic mutation for classic POT, there is no routine genetic test for it ^[10].

However, genetic counseling or testing might be considered by a movement-disorder specialist if your examination, age at onset, family pattern, or associated features suggest a specific inherited disorder ^[11][12]. A doctor may investigate for secondary causes (which could be genetic or acquired) if you experience “red flags” such as:

• An EMG showing a tremor slower than 13 Hz (often categorized as a “slow” or “pseudo-orthostatic tremor”) ^[13][14].
• Additional progressive symptoms like clumsiness (ataxia), neuropathy, or parkinsonism (a group of neurological symptoms including stiffness, slowness of movement, and resting tremor) ^[12].
• A strong, multi-generational family history of other neurological disorders, intellectual disabilities, or early-onset movement disorders ^[15].

These features do not mean you definitely have a genetic disease; rather, they are clinical signs that warrant a broader evaluation for secondary causes ^[14][12]. A movement-disorder neurologist or a genetic counselor can help decide whether testing is appropriate for your specific situation and if it would change your treatment plan ^[6].