PubMed · 5196857
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L Valvanne. 1969. [Editorial. Taking positions].. https://pubmed.ncbi.nlm.nih.gov/5196857/
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The apparent associations between fragile X mutations and nearby microsatellites may reflect both founder effects and microsatellite instability. To gain further insight into their relative contributions, we typed a sample of 56 unrelated control and 37 fragile X chromosomes from an eastern Finnish population for FMR1 CGG repeat lengths, AGG interspersion patterns, DXS548, FRAXAC1, FRAXE and a new polymorphic locus, Alu-L. In the controls, the most common FMR1 allele was 30 repeats with a range of 20 to 47 and a calculated heterozygosity of 88%. A strong founder effect was observed for locus DXS548 with 95% of fragile X chromosomes having the 21 CA repeat (196 bp) allele compared to 17% of controls, while none of the fragile X but 69% of controls had the 20 repeat allele. Although the FRAXAC1 locus is much closer than DXS548 to FMR1 (7 kb vs. 150 kb), there was no significant difference between fragile X and control FRAXAC1 allele distributions. The FRAXE repeat, located 600 kb distal to FMR1, was found to show strong linkage disequilibrium as well. A newly defined polymorphism, Alu-L, located at approximately 40 kb distal to the FMR1 repeat, showed very low polymorphism in the Finnish samples. Analysis of the combined loci DXS548-FRAXAC1-FRAXE showed three founder haplotypes. Haplotype 21-19-16 was found on 27 (75%) of fragile X chromosomes but on none of controls. Three (8.4%) fragile X chromosomes had haplotypes 21-19-15, 21-19-20, and 21-19-25 differing from the common fragile X haplotype only in FRAXE. These could have arisen by recombination or from mutations of FRAXE. A second haplotype 21-18-17 was found in four (11.1%) fragile X chromosomes but only one (1.9%) control. This may represent a more recent founder mutation. A third haplotype 25-21-15, seen in two fragile X chromosomes (5.6%) and one (1.9%) control, was even less common and thus may represent an even more recent mutation or admixture of immigrant types. Analysis of the AGG interspersions within the FMR1 CGG repeat showed that 7/8 premutation chromosomes lacked an AGG whereas all controls had at least one AGG. This supports the hypothesis that the mutation of AGG to CGG leads to repeat instability and mutational expansion.
The news about the discovery of Röntgen's new rays spread over Finland quite early, and the first Finnish writing about the rays appeared in February 1896. The first x-ray machine was installed in 1897. Proper training of radiologists began, however, at a comparatively late date. For a long time the position of radiologists remained a subordinate one. Radiology had the nature of a spare time hobby, because in most hospitals surgeons treated x-ray machines as a sideline. Because of this, scientific research work was delayed. The specialty of x-ray diagnosis and therapy was, however, established in 1921, and the Finnish Society of Radiology was founded in 1924. The first radiotherapy department with its own beds was opened in 1936 in Helsinki. In 1950, the first professor of medical radiology was appointed at the University of Helsinki. The Finnish Cancer Society played an important role in developing the radiotherapy net in the country by supplying cobalt devises and auxiliary hospital activities in the 1960s. In the early 1960s roentgen diagnosis and radiotherapy were separated into two distinct disciplines. There are now five medical faculties with chairs in radiation oncology. The country is divided into five regions for cancer care. The managing groups in each region are headed by the professor of radiotherapy and oncology. The radiation oncologists in Finland are involved in diagnosis and staging of cancer and are responsible for radiation therapy, chemotherapy and hormones. They are responsible for follow-up of treated patients, their own wards, and the general care of their patients.
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