Cholestasis Familiaris Groenlandica/ Byler-like disease in Greenland — A population study

Objectives. Cholestasis Familiaris Groenlandica (CFG, or progressive familiar intrahepatic cholestasis type 1 (PFIC1)) is a very common lethal recessive inherited disease in Greenland. A missense mutation, 1660G>A (asp554asn) in the gene ATP8B1 causes the disease (Klomp et al. 2000). Study design. A family study examining medical files from the period 1951-2003 from East Greenland resulted in 46 cases of PFIC1 and more than 220 relatives showing carrier status. Further, random blood sample testing 953 anonymous persons from 11 major cities or districts all over Greenland have been analysed for carrier status of the mutation. Methods. A sensitive PCR method is developed to distinguish between normal and mutant alleles for ATP8B1 in the Greenland population. Results. The mutation 1660G>A is found in all areas of Greenland, and the frequency of the mutant allele vary all over the country. A shockingly high frequency for the mutant allele is found in East Greenland in Ittoqqortoormiit (0.16) and in Tasiilaq (0.077), whereas in Northwest Greenland lower frequencies are found in Uummannaq and Ilulissat (0.032), and Maniitsoq (0.005). Conclusions. The high frequency of the mutation in East and Northwest Greenland strongly indicates that routine screening of the population for carrier status should be done. Keywords: Cholestasis Familiaris Groenlandica, intrahepatic cholestasis, Byler disease, population study in Greenland, most common recessive lethal disease