Fainted history in both myself and my father. Can it be related?

Question

I am a twenty five year old male, pretty fit, no known conditions. I fainted last night for a few seconds and although I will get it checked out, it has to wait for a week or two so I thought I'd get an opinion here.

A very similar incident also happened a year and a half ago.

In both cases, I was sitting on the floor/lying down for twenty or more minutes. I got up and within about ten seconds, I felt dizzy and lost consciousness and fell down. I regained it within ten seconds and was completely okay. I remembered everything upto the feeling dizzy part.

The thing that worries me is that my dad has also had fainting spells of about one every year for the last three years (although not due to standing up suddenly). I'm not sure what his diagnosis is.

Given a fainting history on standing in a young, otherwise healthy male, and a fainting history in his father, can the two be related? What might be the causes?

Answer 1

There is, unfortunately, no yes or no answer to this, especially not on-line. However, these information can help:

There can be various underlying causes of fainting, mostly cardiovascular or neurological. It is important to note that same pathophysiological mechanisms may be a part of different clinical syndromes. Some of these (classification adjusted for laypersons) include:

• vasovagal syncope (neurocardiogenic syncope)

• orthostatic syncope (usually caused by orthostatic hypotension) - this is a subset of syncope caused by peripheral circulatory impairment

• various cardiac problems

• hypoglycaemia

• hypoxia

• reflexive anoxic seizures (RAS)

• loss of consciousness can be caused by an epileptic seizure or even a stroke, and should be distinguished from a syncope.

etc.

The fact that you faint after standing up is certainly one component of it, but as this article suggests, even that can be classified under different clinical syndromes (peripheral circulatory impairment or neurocardiogenic syncope, e.g.). This is why it is best practice to have this condition checked by a physician. Diagnosis cannot be made on-line.

To answer your other question, whether the condition is hereditary, it may, but doesn't have to be. The only way to determine this is to find the cause of fainting in both cases, that is in your and in your father's case.

On a general note, conditions caused by genetic disorders (i.e. mutations) may be monogenic (mutation is found on a single gene) and polygenic (mutations are on several genes, and one has to inherit more than one, for a condition to manifest). Than, there is a matter of a pattern in which the condition is passed on - whether the condition is dominant or recessive (i.e. whether the condition will manifest itself if you have the gene for it from one parent, or only if you inherited a certain mutation from both parents). In the end, there are multy-factorial conditions:

Very few health conditions are only caused by genes – most are caused by the combination of genes and environmental factors. (from NHS).

The claim very few is, as anongoodnurse noticed, proportional to overall number of diseases, but there are still a lot of conditions that are genetic.

So the matter of whether the conditions in a parent and child are connected isn't always straight-forward, but the place to start is definitely to determine the aetiology in both cases, which can be done by a physician (in person).

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References:

1. Essentials of Clinical Neurology: Neurology History and Examination Chapter 8: Episodic loss of consciousness

2. NHS: Fainting - Causes

3. NHS: Genetics - Genetic inheritance