Clefting of the lip and or palate is the most common craniofacial birth anomaly. Globally cleft lip/palate is more common than cleft palate occurring isolation. Not so in Finland, in Finland the prevalence of cleft palate is more than double the European average.
Using this fact as a starting point and by analysing genomic data together with patient diagnosis codes, national registry data and then testing their genetic findings using gene editing technology, a team from the University of Helsinki and Helsinki University Hospital, together with colleagues from several units in the USA and Estonia, have discovered genetic variants that explain why isolated cleft palate is so common in Finland.
By analysing over 500,000 samples, approximately 10% of the Finnish population, they found that 3 genetic variants, including one close to the gene IRF6 are particularly common in the Finnish population and account for the extra cases of cleft palate.
The team connects this genetic data to Finland’s statistically significant geographic distribution of cleft palate cases, which become more frequent from the southwest to the northeast. This regional distribution of cleft palate has not been observed anywhere else in the world.
Besides explaining why cleft palate is unusually common in Finland, their data highlights a region close to the gene IRF6 that is a ‘hot spot’ for several distinct forms of oro-facial clefting.
This research also explains, in part, why some patients have cleft palate and others have a cleft lip.