The secretion of the ABH antigens in saliva was tested in indigenous individuals of several populations: Icelanders in Reykjavik and Husavik (northeastern Iceland), Aland Islanders, Finno-Ugrians (Finns, Finnish Lapps, Komi) and Eskimos (Augpilagtok, northwestern Greenland). The frequencies of ABH non-secretors among the Icelanders (28-36%) were among the highest ever noted in Europeans. Among Alanders and Swedes on the Finnish mainland the frequency (around 20%) was comparable to Swedish values but considerably higher than among Finns (13-14%). The values among northeastern Finns and Komi (about 9%) were intermediate between values among Lapps (below 5%) and Scandinavians (15-26%), excluding Icelanders (28-41%). The average frequency of non-secretors among Lapps in Finland (2.2 +/- 0.5%) was the lowest observed among white populations. Like many other arctic populations of the Mongolian race, the Greenland Eskimos had a very low frequency of non-secretors. It is probable that the non-secretor allele ABH*se was absent from the ancient Lapps and Greenland Eskimos but introduced by invading populations. It is concluded that the ABH*se allele frequencies vary much more among northern European populations than hitherto appreciated. Recent studies indicate that the non-secretor status of the ABH blood group substances in mucous body fluids is associated with pathological conditions of the mucous membranes of the embryologically related digestive and respiratory systems, particularly with duodenal ulcer and gastric (pre)malignancies but probably also with pulmonary dysfunction. In view of these disadvantages of the ABH non-secretor status the high frequency of ABH*se in Icelanders is a paradoxical phenomenon. The frequency of ABH non-secretors among the founders (Vikings) of Iceland may have been considerably higher than among the present populations in northwestern Europe. The increase in northwestern direction of the ABH*se allele frequencies supports this hypothesis; the dilution effect has not been as strong in Iceland as on the European continent.
To test the pathogenetic role of the phenotype MZ of alpha 1-antitrypsin/alpha 1-protease inhibitor (PI) in acute anterior uveitis (AAU), 156 patients with AAU were examined. Sera of all patients and 120 healthy controls were PI-typed using isoelectric focusing. There were no significant differences in PI MZ frequencies either between the patients with AAU (4.5%) and the controls (4.2%), or between AAU patients with associated rheumatic diseases (4.8%) and AAU patients with no associated disease (4.3%). The results indicate that the PI MZ type is not closely associated with AAU among Finns.
A mutation of the LDL receptor gene very common among Finnish patients with heterozygous familial hypercholesterolemia (FH) was identified. This mutation, designated as FH-North Karelia, deletes seven nucleotides from exon 6 of the LDL receptor gene, causes a translational frameshift, and is predicted to result in a truncated receptor protein. Only minute quantities of mRNA corresponding to the deleted gene were detected. Functional studies using cultured fibroblasts from the patients revealed that the FH-North Karelia gene is associated with a receptor-negative (or binding-defective) phenotype of FH. Carriers of the FH-North Karelia gene showed a typical xanthomatous form of FH, with mean serum total and LDL cholesterol levels of 12 and 10 mmol/liter, respectively. This mutation was found in 69 (34%) out of 201 nonrelated Finnish FH patients and was especially abundant (prevalence 79%) in patients from the eastern Finland. These results, combined with our earlier data on another LDL receptor gene deletion (FH-Helsinki), demonstrate that two "Finnish-type" mutant LDL receptor genes make up about two thirds of FH mutations in this country, reflecting a founder gene effect. This background provides good possibilities to examine whether genetic heterogeneity affects the clinical presentation or responsiveness to therapeutic interventions in FH.
Ninety-two cases of granular corneal dystrophy, most of them belonging to 5 pedigrees are described. The age of manifestation in this Finnish type of granular dystrophy is first in the end of the second decade, and visual acuity is in mean normal through the whole life. An autopsy study showed no changes outside cornea elsewhere in the eyeball. In one family with granular dystrophy, another type of dystrophy, hereditary fleck dystrophy of the cornea, was accidentally found.
Previously it has been reported that Greenland Inuit (Eskimos) from the Uummannaq district display low levels of plasma cholesterol and triglycerides and relatively high levels of high density lipoprotein (HDL) when compared with healthy Danish control subjects (Lancet 1971;1:1143-1146). Here we present data obtained in 1989 that show the following. In a group of 133 healthy adult Greenland Inuit from Nanortalik, the levels of plasma cholesterol and low density lipoprotein (LDL) cholesterol (6.39 and 4.39 mmol/l, respectively) were slightly higher than "normal" values found in western societies, whereas the HDL cholesterol level was markedly higher (1.64 mmol/l). Compared with most Caucasian populations, the Inuit population we studied exhibits a high apolipoprotein (APO)E*4 allele frequency (0.229), whereas the APOE*2 allele frequency was extremely low (0.015). In contrast to Caucasian populations, in the Inuit population the apoE polymorphism showed only a minor influence on the plasma lipid and (apo)lipoprotein levels, as evaluated by multiple regression analysis, with the exception of apoE levels. This absence of an effect could be explained by the low very low density lipoprotein (VLDL) plus intermediate density lipoprotein (IDL) cholesterol levels. The contributions of eicosapentaenoic acid and linoleic acid to the total amount of fatty acids in plasma cholesterol esters differed markedly from those reported in 1971 for another Greenland Inuit population (3.2% versus 15.8% and 49.5% versus 20.4%, respectively), thereby resembling values now found in the average western population. Even in those Inuit who reported exclusive consumption of the traditional Inuit diet (13% of the population), the fatty acid composition of the plasma cholesterol esters closely resembled the values measured in western populations.(ABSTRACT TRUNCATED AT 250 WORDS)
During family and population studies in a Finnish isolate (Salla), a variant of alpha 1-antitrypsin, tentatively called PI MSAL was found. On isoelectric focusing this variant was slightly cathodal to M3. With the aid of acid starch gel electrophoresis, differentiation from M3 proved reliable, because the variant was unstable in that system. The variant also showed an increased lability at + 56 degrees C and physiological pH and a decreased stability at pH 4.5 and room temperature compared to the other M subtypes. By genealogical studies it was possible to trace a common ancestor, a settler arriving to the parish around 1680, for the three families where the variant was found.
Familial hemiplegic migraine (FHM), a rare autosomal dominant subtype of migraine with aura, has been linked to two chromosomal loci, 19p13 and 1q23. Mutations in the Na+K+-ATPase alpha2 subunit gene, ATP1A2, on 1q23 have recently been shown to cause familial hemiplegic migraine type 2 (FHM2). We sequenced the coding regions of this gene in a Finnish chromosome 1q23-linked FHM family with associated symptoms such as coma and identified a novel A1033G mutation in exon 9. This mutation results in a threonine-to-alanine substitution at codon 345. This residue is located in a highly conserved N-terminal region of the M4-5 loop of the Na+,K+-ATPase. Furthermore, the T345A mutation co-segregated with the disorder in our family and was not present in 132 healthy Finnish control individuals. For these reasons it is most likely the FHM-causing mutation in this family.
We have performed a reinvestigation of a family with a presumably autosomal recessive form of pseudoinflammatory dystrophy, which we have followed for 25 years. The symptoms in this family are subretinal haemorrhages appearing at age 13-40 years in the central fundus, resulting in glial cicatrication in the outer retinal layers, progressive myopia and profound choroidal atrophy in the advanced stages of the disease. During the follow-up study, a new affected subject was found in the younger generation, and two collateral cases, who had earlier been considered as probably affected subjects, were now considered to have other fundus affections. The new case is the daughter of an affected female. The possibilities of an autosomal dominant mode of inheritance or pseudodominance are discussed. Extended genealogical studies showed that the parents of all the affected subjects, with the exception of the new case, have their origin in an area which was isolated until recently and have several common ancestors within the last 8-10 generations. Recessive inheritance also logically explains the appearance of the disease in so few other members in the vertical line of the family. To this fundus dystrophy, the rule of Lenz seems to apply: If more or less the same phenotype can be caused by both a recessive and a dominant gene, the phenotype caused by the recessive gene is generally manifested earlier and by more severe symptoms.
The still living members of the original bleeder family on the Aland Islands described by von Willebrand in 1926 have been reinvestigated by using modern laboratory techniques for the measurement of the Factor VIII complex and with regard to platelet aggregation. The low level of F VIII : C activity demonstrated in 1957 could be confirmed in some of the family members, who however all had only mild bleeding symptoms. More consistently, in 6 out of 10, a low F VIIIR : Ag was found; all of those also had a low F VIII : RCoF. In none of the members were excessively low values for any of the parameters found. However, the spectrum of the whole F VIII complex indicates that the original family described by von Willebrand belongs to von Willebrand's disease, type I.