Genealogy Data Helps Track Back Rare Disease Alleles to Quebec Founder Families

A Canadian team has harnessed genealogical data from Quebec to retrace the history of a rare recessive disease called “chronic atrial and intestinal dysrhythmia” (CAID), using a computational approach for inferring rare allele transmission history.

Researchers from McGill University and elsewhere used their software package, known as ISGen, to analyze past transmission of CAID alleles with the help of high-quality genealogical data for more than 3.4 million individuals of European ancestry in the Canadian province. The approach traced the rare heart and digestive condition back to French settlers who arrived in the region in the early 17th century, the team reported in the American Journal of Human Genetics.

You can read more in the research team’s announcement at: A free registration may be required, however.


I’d LOVE to read the article, but apparently the “free registration” requires that one is employed in some related industry or research. I’m retired, so I can’t register.


    Ditto for me. And I would like to know who the family founders are.


    It never gives the actual info re: who the founding families were, no names were listed. The article is really just about how they were able to find out how and who the families were. Not really any use (or interest, imo) to the average person doing family research. “With this approach, the researchers tracked the CAID allele back to two families containing as few as five founder individuals. Based on estimated CAID allele frequencies in the current Quebecois population, which varied by region, they predicted that as many as one in every 24,025 individuals in the province are asymptomatic carriers of the CAID mutation.”


If someone is able to get in to the article, please post the surnames here. merci!


McGill’s report is here:

A .pdf downloadable here


Reconstitution of ascending genealogies from the BALSAC population database 14 for 8 French-Canadian cases identified 64 common ancestors married in the seventeenth century in France or in Quebec City. Identity-by-descent analysis supported the observation that all the French-Canadian CAID cases derived from the eastern part of Quebec and shared a common ancestral haplotype for SGOL1, whose age was estimated at 13 ± 4 generations. Allele dropping analysis identified a founder couple, married in France in 1620, whose likelihood of being the mutation carriers exceeded that for other founders by a factor of >100.


The article does not mention surnames, but does say this…

From some 3 million records, the team had access to genealogical data for as many as 17 generations and around 3.4 million individuals, including 2.7 million individuals with associated geographical information. The analysis also relied on genotyping data from a Quebec regional population sampling project and on Illumina array-based genotypes from 11 individuals with CAID and one individual carrying one copy of a CAID-causing mutation, found in the SGO1 gene.

So if you have access to your DNA results, maybe you can use this.

I know, it’s maddening. I have French Canadian ancestry on both sides – and I would like to know more…

As far as getting in to read the article goes, you need to register and be patient regarding their confirmation email.


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