First Cousins Marrying Query

[Phil L]

I have noted that in my direct line the first cousins married way back in the 1600's. I also know that my uncle and his Grand father (my great grandfather) had epilepsy. I was told that epilepsy can effect every second generation. My questions could the marriage of the first cousins be the cause of the epilepsy?

[Guy Etchells]

There is and has been a lot of misinformed speculation about epilepsy.
The simple answer to your question is no.

Epilepsy may be classed in three main categories-
Symptomatic epilepsy - where there is a known cause, such as a head injury.

Idiopathic epilepsy - where despite investigation, no apparent cause can be found. This could be inherited from one or both parents

Cryptogenic epilepsy - where, like idiopathic epilepsy, no apparent cause can be found. However, there is strong evidence to suggest that it may be the result of brain damage.

There is some research that suggests one cause could be a mutated gene that disrupts the Ion channels (these help transmit tiny amounts of electricity between cells).
More research deeds to be done on this.
In addition there are other specific “types” of epilepsy which are passed through generations.

The risk of a child inheriting epilepsy from the mother is about 5%. The risk from inheriting from their father about 2% which is about the normal risk of developing epilepsy.
So although it could be inherited from the marriage of first cousins the risk is too low to be ascertained.

Cheers
Guy

[DorothySandra]

First cousins marrying is never the cause of any medical problem: it might increase the incidence of some genetics traits, but it wouldn't affect problems only inherited from one parent, such as haemophilia.

Repeated intermarriage between the carriers, over numerous generations would increase the risk, and might even cause a harmless trait to become a problem (but this is more easily demonstrated at Crufts than in human history)

[Peter Goodey]

IIRC the chances of any adverse genetic consequence of a first cousin marriage is no more than that of a woman over 40 giving birth. Subsequent non-cousin marriages return the risks to normal.

[birdlip]

There have been other more general threads on this forum re the level of risk associated with first cousin marriages, it was fairly common I think. Charles Darwin of course, famously, married his first cousin.