family based linkage study - design and analysis

Question

[User6891]

Hello,

We want to perform a linkage analysis study (using an Illumina SNP array) in a family affected with an autosomal dominant disorder

Could someone give some advice on how much family members (affected + unaffected) we would need? I suppose that the more family members you have, the better it is. And is it also necessary to genotype the unaffected parent of affected children? And what about the grandparents, do you need them both? I've read that most tools can handle missing data, but I'm not sure to what extent.

I've read that tools like MERLIN or PLINK are suited to perform the data analysis. Are there other recommended ones?

Regards

[User 59]

What's the rationale for doing this on an array rather than via exome sequencing just out of interest?

[User6891]

It's to narrow down the regions-of-interest where the causal variant can be located. We have done exome sequencing for two family members, but too expensive to do it for all.