Adam’s Journal

With Father’s Day around the corner, I’ve been thinking about my dad, who passed away two years ago this month.

I always remember him – and his father before him – having a slight tremor in his hand. He would have a drink or two to calm it, but especially in his later years, that was not enough.

In his 80s and, finally, his 90s, the shaking in his hands became so pronounced that it was debilitating. He was nearly unable to type on a computer keyboard, and simply signing his name was an arduous task that could take the better part of an hour.

Given this familial history, are my brother and I destined to inherit this condition?

Dr. Scofield Prescribes

Commonly called familial tremor, what you’re describing sounds like what’s known more technically as essential tremor. It’s a neurological condition that runs in families.

Unlike Parkinson’s disease, which also causes shaking in the hands but is accompanied by a host of other neurological symptoms, essential tremor primarily causes tremors and is generally not associated with the progressive neurological decline seen in Parkinson’s. That said – and as you described – it can nevertheless have a profound impact on one’s quality of life and ability to perform countless day-to-day tasks.

There is, as you’ve surmised, a strong genetic component to essential tremor. But the fact that your father and paternal grandfather had the condition does not predestine you, your brother or any other siblings to their fate.

Essential tremor shares many characteristics with what are called “autosomal dominant” disorders. These are conditions where, if one parent has them, each child (regardless of sex) has a 50% chance of inheriting them.

However, research has found that no single gene causes essential tremor. Multiple genes likely contribute.

So while the overall risk for you and each of your siblings inheriting the genes that predispose you to the condition is still likely in the neighborhood of a coin flip, the picture is much more complicated than that.

I promise this is the end of the genetics lesson, but essential tremor displays a trait that geneticists call variable penetrance. Put simply, it means that just because you inherit the genes doesn’t mean you’ll develop the condition.

And even if you do, your symptoms may not be as severe as your father’s were.

We don’t fully understand why this is the case. Environmental factors may also play a role, influencing whether symptoms surface and, if they do, how profound they might be.

I’d encourage you to pay attention to fine-motor tasks: things like signing documents, holding a cup of coffee, or taking photos with a smartphone.

Even a subtle tremor would be a signal. With you now in your late 50s, symptoms would typically, but not always, begin to appear by this time. If you haven’t seen any symptoms, it’s an encouraging sign that you will not continue this family legacy.

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Dr. Hal Scofield is a physician-scientist at the Oklahoma Medical Research Foundation, and he also serves as Associate Chief of Staff for Research at the Oklahoma City VA Medical Center. Adam Cohen is OMRF’s senior vice president and general counsel. Send your health questions to contact@omrf.org.