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H Forsius

Publications and source records attributed to H Forsius.

At least 37 records · Page 2Linked to original sources
PubMed1991

Localization of the Aland Island eye disease locus to the pericentromeric region of the X chromosome by linkage analysis.

Aland Island eye disease (AIED) is an X-chromosomal disorder characterized by reduced visual acuity, progressive axial myopia, regular astigmatism, latent nystagmus, foveal hypoplasia, defective dark adaptation, and fundus hypopigmentation. The syndrome was originally reported in 1964 in a family on the Aland Islands. To determine the localization of the AIED gene, linkage studies were performed in this family. total of 37 polymorphisms, covering loci on the entire X chromosome, were used. By two-point analysis the strongest evidence for linkage was obtained between AIED and DXS255 (maximum lod score [Zmax] 4.92 at maximum recombination fraction [theta max] .00). Marker loci DXS106, DXS159, and DXS1 also showed no recombination with AIED. Other positive lod scores at theta max .00 were obtained with markers localized in the XY homologous region in Xq13-q21, but the numbers of informative meioses were small. Multilocus linkage analysis indicated that the most probable location of AIED is in the pericentromeric region between DXS7 and DXS72. These results rule out localizations of AIED more distal on Xp that have been proposed by others. Our data do not exclude the possibility that AIED and incomplete congenital stationary night blindness are caused by mutations in the same gene. This question should be resolved by careful clinical comparison of the disorders and ultimately by the molecular dissection of the genes themselves.

Albinism, Ocular↗
PubMed1990

Rod-cone dystrophy of the retina. Continuation of a family study described in 1923.

In 1923 Alkio described a sibship with 4 children showing macular dystrophy. In the literature this has been classed among the cone dystrophy group. However, Alkio's patients later became completely blind by the age of 50. According to the hospital records one of them showed marked destruction and pigment degeneration throughout the fundus. The daughter of one of those affected has healthy eyes, but two of her three sons are affected in the same way as their grandfather. They were studied by us in 1987. These two males showed the bull's eye type of macular dystrophy with visual acuity of 20/30 resp 20/50, marked dyschromatopsia, central scotoma in the visual field for weak markers, extinguished ERGs and subnormal EOGs. Dark adaptation was considered pathological especially during the cone phase. The peripheral fundus was within normal limits. The parents of the two patients have a common ancestor born in 1720. Autosomal recessive inheritance is therefore very likely. We think that the disorder is closer to the rod-cone dystrophy group than to cone or cone-rod degenerations.

Adolescent↗
PubMed1989

Haplotype and multipoint linkage analysis in Finnish choroideremia families.

Multipoint linkage analysis of choroideremia (TCD) and seven X chromosomal restriction fragment length polymorphisms (RFLPs) was carried out in 18 Finnish TCD families. The data place TCD distal to PGK and DXS72, very close to DXYS1 and DXYS5 (Zmax = 24 at theta = 0) and proximal to DXYS4 and DXYS12. This agrees with the data obtained from other linkage studies and from physical mapping. All the TCD males and carrier females studied have the same DXYS1 allele in coupling with TCD. In Northeastern Finland, 66/69 chromosomes carrying TCD had the same haplotype at loci DXS72, DXYS1, DXYS4, and DXYS12. The same haplotype is seen in only 15/99 chromosomes not carrying TCD. Moreover, in 71/104 non-TCD chromosomes, the haplotype at six marker loci is different from those seen in any of the 76 TCD chromosomes. This supports the previously described hypothesis that the large Northern Finnish choroideremia pedigrees, comprising a total of over 80 living patients representing more than a fifth of all TCD patients described worldwide, carry the same mutation. These linkage and haplotype data provide improved opportunities for prenatal diagnosis based on RFLP studies.

Choroideremia↗
PubMed1988

Exfoliation syndrome in various ethnic populations.

This introductory lecture to the epidemiological session in the Workshop on the Exfoliation Syndrome (ES) gathers together figures for the prevalence of ES around the world. Prevalence figures from published reports are shown in the text separately for each country. Four ways of comparing the prevalences are used. 1) Prevalences in people over 60 years of age, 2) Percentages of glaucoma in persons with ES, 3) Percentages of ES in patients with glaucoma or ocular hypertension, with separate statistics for the proportion of capsular glaucoma in patients treated with laser trabeculoplasty (LTP), 4) Prevalence of ES in patients with cataract. The major differences in prevalence can partly be explained by the different techniques used in the investigations. Very few authors have studied people in different countries, which is the best way of obtaining comparable results. The author has personally studied Finns, Lapps, Eskimos in Greenland, Canada and Alaska, Icelanders, populations in Tunis, India and Peru and four populations in the USSR by the same technique. The prevalences vary from 0% in Eskimos to 21% in Finns over 60 years of age, and are at the same high level in Lapps, Finns, Russians in Novosibirsk and Icelanders, but significantly lower in all the others. The results support the opinion that ES is not uniformly distributed in all countries, and this is confirmed by many reports from different countries in this workshop.

Africa↗
PubMed1988

Linkage relationships and gene order around the locus for X-linked retinoschisis.

X-linked recessive retinoschisis (RS) is a hereditary disorder with variable clinical features. The main symptoms are poor sight; radial, cystic macula degeneration; and peripheral superficial retinal detachment. The disease is quite common in Finland, where at least 300 hemizygous males have been diagnosed. We used nine polymorphic DNA markers to study the localization of RS on the short arm of the X chromosome in 31 families comprising 88 affected persons. Two-point linkage results confirmed close linkage of the RS gene to the marker loci DXS43, DXS16, DXS207, and DXS41 and also revealed close linkage to the marker loci DXS197 and DXS9. Only one recombination was observed between DXS43 and RS in 59 informative meioses, giving a maximum lod score of 13.87 at the recombination fraction .02. No recombinations were observed between the RS locus and DXS9 and DXS197 (lods between 3 and 4), but at neither locus was the number of informative meioses sufficient to provide reliable estimates of recombination fractions. The most likely gene order on the basis of multilocus analysis was Xpter-DXS85-(DXS207,DXS43)-RS-DXS41-DXS 164-Xcen. Because multilocus linkage analysis indicated that the most probable location of RS is proximal to DXS207 and DXS43 and distal to DXS41, these three flanking markers are the closest and most informative markers currently available for carrier detection.

Female↗
PubMed1987

Choroideremia: close linkage to DXYS1 and DXYS12 demonstrated by segregation analysis and historical-genealogical evidence.

Linkage studies using restriction fragment length polymorphisms were conducted in the X-linked disorder, choroideremia, designated TCD for Progressive Tapeto-Choroidal Dystrophy. Previously demonstrated close linkage with locus DXYS1 was confirmed (lod 11.44 at 0 recombination distance). In addition, locus DXYS12 was found to be closely linked with TCD (lod 3.31 at 0 recombination distance). The disease mainly occurs in three large kindreds in remote Northern Finland. While formal genealogical proof is lacking, all presently living (more than 80 affected males and 120 carrier females) probably originate from a common founder couple born in 1644 and 1646, twelve generations ago. All 36 patients and 48 carriers tested from the three kindreds had the same haplotype (TCD/DXYS1, 11kb/DXYS12, 1.6kb). Given that at least 105 female meioses transmitting TCD have occurred since 1650 in these kindreds, extremely close linkage between TCD, DXYS1 and DXYS12 is suggested. The above haplotype is a very useful diagnostic tool in these TCD families. We suggest that our historical-genealogical approach to linkage analysis may be possible elsewhere in similar isolated populations.

Alleles↗
PubMed1987

X-linked retinoschisis is closely linked to DXS41 and DXS16 but not DXS85.

A linkage study was carried out in nine families with 24 males affected by X-linked recessive retinoschisis (RS), using three polymorphic DNA probes from the distal segment of Xp. Close linkage of the disease locus with markers DXS41 (probe p99-6) and DXS16 (pXUT23) was found, confirming the location of the RS gene on the distal short arm of the X chromosome. Lod scores for linkage with DXS85 (probe 782) were negative.

Genes, Recessive↗
PubMed1986

Increase in type I and type IV collagenolytic activity in primary cultures of keratoconus cornea.

The collagenolytic activities were assayed in fibroblast cultures established from ten keratoconus and six control corneal explants. The assays included those for both type I and type IV collagenase. The amount of free, directly assayable type I collagenase was highly increased in the media of keratoconus primary cell cultures. Also the activity of type IV collagenase was increased significantly in these cultures but was detectable only after proteolytic activation. The total hydroxyproline content of keratoconus corneas was decreased when compared to controls. However the activity of the prolyl-4-hydroxylase, reflecting the biosynthesis of collagen, was higher in the keratoconus corneal tissue, either expressed per DNA, soluble protein or hydroxyproline content of corneas. The enhancement in collagenolytic processes could explain the pathological tissue destruction in keratoconus corneas and this enhancement is maintained still in primary cultures of keratoconus corneal fibroblasts.

Adolescent↗
PubMed1983

Seasonal variations in retinal detachment in Northern Finland and Novosibirsk.

Retinal detachments have a tendency to occur more commonly in spring and summer than in winter. Two new series are presented here, the first collected in Northern Finland at latitudes 64 degrees-70 degrees and the second from Novosibirsk, at a much lower latitude, 55 degrees N, but with an equally long winter. A statistically significant seasonal variation is found in both. The highest incidence peak is seen in June in Oulu and in July in Novosibirsk, the difference between the prevalence curves was, however, not statistically significant. The Oulu series shows a statistically highly significant seasonal variation in low refractive errors but no seasonal difference in high myopia and aphakia.

Climate↗
PubMed1983

Granular corneal dystrophy with late manifestation.

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.

Adult↗
PubMed1980

Forsius-Eriksson syndrome: its relation to the Nettleship-Falls X-linked ocular albinism.

On the basis of clinical data, it had previously been proposed that the Forsius-Eriksson syndrome is identical to Nettleship-Falls X-linked ocular albinism. We performed biopsies of clinically-normal skin in patients with the Forsius-Eriksson syndrome to look for the abnormal melanosomes characteristic of Nettleship-Falls X-linked ocular albinism. There were no abnormalities in the melanosomes of patients with Forsius-Eriksson syndrome. Thus, this syndrome is distinct from the Nettleship-Falls disorder.

Albinism↗