No doubt populations that eat only rice, potatos and corn may never report a problem with celiac ~ unless, of course, some joker decides to put some delicatessen mustard in the meal (made with malt vinegar) ~ then they'll find out! Wahooo.
Like many other genetic conditions they've already discovered a third variant ~ this one controls "intermittent celiac". There's a paper on this discovery among the Skolt Sa'ami. Since this is a small tribe (in Finland) the Finns find it convenient to compare tests with them to nearby Finnish populations that also engage in reindeer herding full time. That way diet and lifestyle are easily factored out.
Unfortunately all these guys (in Finland) live within the expected blastzone of the atomic submarine waste pit at the old Soviet pens on Kola.
One little boom and they're out of test subjects!
The condition may well be far more widespread in the United states simply because a far larger percentage of our population derive from early Fenno-Scandia populations brought here by the Swedes in the mid 1600s to cut down trees ~ later purchased by the Swedes for their shipping industry and navy through deals negotiated with their quasi-ally, equally Protestant England!
This is an hereditary immunological reaction by T-Cells in the small intestine to gluten, found in wheat, barley and rye. It's pretty obvious that sort of thing can get loose in a population totally independent of wheat culture, e.g. folks chowing down on reindeer and seal.
Last evening in some heavy research I discovered the capital city of Lapp province in Finland is Rovaniemi. There are several different spellings and pronunciations given in other Sa'ami languages. For example, Inari Sami: Ruávinjargâ, Northern Sami: Roavenjárga and Roavvenjárga, Skolt Sami: Ruäˊvnjarg. There seems to be a shallow place in the nearby river ~ a ford perhaps ~ referenced here, and maybe a reference to snow or solid ice (in an area with 168 days of snow cover this is meaningful stuff). You could transliterate the name as "Mule's Crossing", which is the older name of Seymour, Indiana, and there was/is a substantial Sa'ami settlement there with its own separate grave yard at Uniontown Cemetary.
This stuff keeps me awake. Working on "Brogalis" or "Bogallis" at the moment ~ a "reindeer suit" so that when you went out to work the stock you didn't get dirty ~ same as bib overalls in warmer climates. Need some help here guys ~ and for amaroosia (how it sounds), or emi- ruäˊvnjargg, what the riverside country around Seymour has been called for a couple of centuries.