Genome-wide scan in a nationwide study sample of schizophrenia families in Finland reveals susceptibility loci on chromosomes 2q and 5q

We have previously carried out two genome-wide scans in samples of Finns ascertained for schizophrenia from national epidemiological registers. Here, we report data from a third genome scan in a nationwide Finnish schizophrenia study sample of 238 pedigrees with 591 affected individuals. Of the 238 pedigrees, 53 originated from a small internal isolate (IS) on the eastern border of Finland with a well established genealogical history and a small number of founders, who settled in the community 300 years ago. The total study sample of over 1200 individuals were genotyped, using 315 markers. In addition to the previously identified chromosome 1 locus, two new loci were identified on chromosomes 2q and 5q. The highest LOD scores were found in the IS families with marker D2S427 (Z(max) = 4.43) and in the families originating from the late settlement region with marker D5S414 (Z(max) = 3.56). In addition to 1q, 2q and 5q, some evidence for linkage emerged at 4q, 9q and Xp, the regions also suggested by our previous genome scans, whereas, in the nationwide study sample, the region at 7q failed to show further evidence of linkage. The chromosome 5q finding is of particular interest, since several other studies have also shown evidence for linkage in the vicinity of this locus.

Chromosome 1 loci in Finnish schizophrenia families

We have earlier reported evidence for linkage to two regions on chromosome 1q32--q42 in schizophrenia families collected for two separate studies in Finland. Here we report the results of a fine mapping effort aimed at further definition of the chromosomal region of interest using a large, population-based study sample (221 families, 557 affected individuals). Most affecteds (78%) had a DSM-IV schizophrenia diagnosis and the remaining had schizophrenia spectrum disorders. We genotyped a total of 147 microsatellite markers on a wide 45 cM region of chromosome 1q. The results were analyzed separately for families originating from an internal isolate of Finland and for families from the rest of Finland, as well as for all families jointly. We used traditional two-point linkage analysis, SimWalk2 multipoint analysis and a novel gamete-competition association/linkage method. Evidence for linkage was obtained for one locus in the combined sample (Z(max) = 2.71, D1S2709) and in the nuclear families from outside the internal isolate (Z(max) = 3.21, D1S2709). In the families from the internal isolate the strongest evidence for linkage was obtained with markers located 22 cM centromeric from this marker (Z(max) = 2.30, D1S245). Multipoint analysis also indicated these loci. Some evidence for association with several markers was observed using the gamete-competition method. Interestingly, the strongest evidence for linkage in the combined study sample was obtained for marker D1S2709, which is an intragenic marker of the DISC1 gene, previously suggested as a susceptibility gene for schizophrenia. These results are consistent with the presence of susceptibility gene(s) in this chromosomal region, a result also implied in other recent family studies of schizophrenia.

Microbial etiology of community-acquired pneumonia in the adult population of 4 municipalities in eastern Finland

To determine the etiology of community-acquired pneumonia in the adult population of a defined area, specific antibody responses in paired serum samples, levels of circulating pneumococcal immune complexes in serum samples, and pneumococcal antigen in urine were measured. Samples (304 paired serum samples and 300 acute urine samples) were obtained from 345 patients > or =15 years old with community-acquired, radiologically confirmed pneumonia, which comprised all cases in the population of 4 municipalities in eastern Finland during 1 year. Specific infecting organisms were identified in 183 patients (including 49 with mixed infection), as follows: Streptococcus pneumoniae, 125 patients; Haemophilus influenzae, 12; Moraxella catarrhalis, 8; chlamydiae, 37 (of which, Chlamydia pneumoniae, 30); Mycoplasma pneumoniae, 30; and virus species, 27. The proportion of patients with pneumococcal infections increased and of those with Mycoplasma infections decreased with age, but for each age group, the etiologic profile was similar among inpatients and among outpatients. S. pneumoniae was the most important etiologic agent. The annual incidence of pneumococcal pneumonia per 1000 inhabitants aged > or =60 years was 8.0.

Genome-wide scan for schizophrenia in the Finnish population: evidence for a locus on chromosome 7q22

We report the results of a four-stage genome-wide scan in a schizophrenia study sample consisting of 134 affected sib-pairs collected in Finland. In stage I we genotyped 370 markers from the Weber 6 screening set ( N = 52 affected sib-pairs); in stage II we followed up 40 markers by typing first-degree relatives of the sib-pairs; in stage III we genotyped 15 markers in 134 families; and in stage IV we genotyped a denser marker map in the two most promising regions, one on chromosome 1 and another on chromosome 7, in all families. Diagnoses were based on three nationwide health care registers and consensus diagnosis based on review of all medical records. The most significant finding was a two-point lod score of 3.18 with marker D7S486 using a dominant model and treating all individuals with either schizophrenia, schizoaffective disorder or other schizophrenia spectrum disorder as affected. Multipoint analysis with MAPMAKER/SIBS resulted in a MLS of 3.53 between markers D7S501 and D7S523 using the broadest diagnostic model, including major depressive disorder and bipolar type I as affecteds in addition to the aforementioned phenotypes. These results were obtained by including in the analyses only individuals from the late settlement region of Finland settled in the 16th century. Additionally, some support was obtained for linkage to chromosome 1, in a region previously identified in a genome-wide scan of a study sample from a sub-isolate of Finland. Our data demonstrate the importance of genealogical information for studies aiming at identification of predisposing loci in complex diseases.

Etiology of childhood pneumonia: serologic results of a prospective, population-based study

BACKGROUND

To investigate the etiology of pediatric community-acquired pneumonia, we conducted a prospective, population-based study covering the total population <15 years of age (n = 8851) in 4 municipalities in eastern Finland.

MATERIALS AND METHODS

The number of patients was 201; chest radiographs were available for all cases and paired sera for serologic assays were available for >90% of cases. The methods included assays for antibody response to 3 pneumococcal antigens, specific pneumococcal immune complex assays and conventional antibody tests for mycoplasmal, chlamydial and viral infections.

RESULTS

Serologic evidence of specific microbial etiology was obtained in 133 (66%) of the pneumonia patients. Bacterial infection was diagnosed in 102 cases (51%) and viral infection in 51 cases (25%). Streptococcus pneumoniae was the most common agent (57 cases; 28%), followed by Mycoplasma pneumoniae (44; 22%), respiratory syncytial virus (43; 21%) and Chlamydia spp. (29; 14%). Haemophilus influenzae was identified in only 6% and Moraxella catarrhalis in only 3% of the children. More than one specific infection was found in 51 patients (25%). The proportion of pneumococcal cases varied from 24 to 36% by age. Mycoplasma infections were seen mostly in patients > or =5 years and Chlamydia infections in patients > or =10 years of age.

CONCLUSIONS

The results of our prospective, strictly population-based study confirm the importance of S. pneumoniae in the etiology of community-acquired pneumonia in children of all ages. M. pneumoniae and Chlamydia pneumoniae are important from the age of 5 years onwards.

Linkage analysis of putative schizophrenia gene candidate regions on chromosomes 3p, 5q, 6p, 8p, 20p and 22q in a population-based sampled Finnish family set

During the past decade numerous studies have been published describing chromosomal regions potentially linked with schizophrenia. Unfortunately, none of these studies has been able to conclusively identify any specific gene that predisposes to schizophrenia. Typically evidence for linkage is seen on large chromosomal regions, as expected, containing tens or even hundreds of genes. Furthermore, attempts to replicate the findings have rarely been successful leaving a confusion about the existence of predisposing genes for schizophrenia in a particular region of the genome. We have carried out linkage analysis in a set of 62 pedigrees rising from a genetically isolated population of Finland with markers on six chromosomal regions earlier suggested to harbor predisposing genes for schizophrenia, namely 3p, 5q, 6p, 8p, 20p, and 22q. We were not able to find significant evidence for linkage on any of these chromosomal regions. However, some support for linkage was found on all studied chromosomal regions, except 3p.

Incidence of community-acquired pneumonia in the population of four municipalities in eastern Finland

Between September 1, 1981, and August 31, 1982, all patients with suspected or confirmed pneumonia among the 46,979 inhabitants of four municipalities in the province of Kuopio, Finland, were reported to a pneumonia register by their attending physicians. In addition, two study pathologists reported all cases of pneumonia found at autopsy, and two permanent registers were checked for retrospective identification of patients. Chest radiographs were obtained from 97% of all patients. The final diagnosis was based on radiologic or autopsy criteria. A total 546 patients (323 males and 223 females) had community-acquired pneumonia; of these, 37% were less than 15 years of age, and 31% were 60 years of age or older. Nineteen percent of the patients had defined chronic conditions, and 42% were admitted to hospital. The case fatality rate was 4%. The overall incidence of community-acquired pneumonia per 1,000 inhabitants per year was 11.6 (13.9 in males, 9.4 in females). The age-specific incidence per 1,000 inhabitants per year was as follows: age < 5 years, 36.0; age 5-14 years, 16.2; age 15-59 years, 6.0; age 60-74 years, 15.4; and age > or = 75 years, 34.2.

Binding of beta-carbolines and tetrahydroisoquinolines by opiate receptors of the delta-type

Effects of various beta-carbolines (BC's) and two tetrahydroisoquinolines (TIQ's) on the specific binding of a natural opiate delta-receptor ligand, leucine enkephalin, have been studied in rat synaptosomal membranes, and compared with the effects on the binding of mu-receptor ligands dihydromorphine and naloxone. Harmaline (7-MeO-1-Me-dihydro-BC) was the most potent compound studied (Ki value 3.5 microM), while the two TIQ's (salsolinol and salsolidine) were less potent than BC's (Ki greater than 100 microM) in inhibiting the binding of delta-receptors. In general, BC's showed more affinity for delta-receptors than for mu-receptors; salsolinol was more potent against the binding of mu-receptors. Inhibition of binding was generally of the competitive type: Kd values increased and Bmax values were not altered. The Na dependence suggests that BC's and salsolinol are antagonists or partial agonists of opioids. Since the binding affinity of BC's and TIQ's was on the micromolar level only, the opiate receptors do not appear to be the major sites of action for BC's or TIQ's.

Effect of discontinuation of biguanide therapy on metabolic control in maturity-onset diabetics

Control of blood-glucose levels was monitored for 12 wk after withdrawal of biguanides in a group of 118 diabetic patients treated with biguanides (alone or in combination with sulphonylurea) from a population of 39,200. The mean fasting blood-glucose level rose during the first 2 wk from 9.2 +/- 0.3 to 11.3 +/- 0.4 mmol/l (p less than 0.001) and the mean urinary-glucose excretion from 11.7 +/- 3.7 g/24 h to 36.5 +/- 5.5 g/24 h (p less than 0.001), respectively. The change in blood-glucose concentration did not depend on age, sex, bodyweight, or duration of diabetes or biguanide treatment. The mean increase in blood-glucose was similar (2.1-3.1 mmol/l) in subjects with their initial blood-glucose level less than or equal to 6.0 mmol/l, 6.1-11.0 mmol/l, and greater than or equal to 11.1 mmol/l. There were no changes in blood-lipids or bodyweight during the observation period. Biguanides reduced blood-glucose levels in most patients with maturity-onset diabetes. The hypoglycaemic effect was similar in subjects with normal and increased bodyweight and did not depend on the duration or severity of diabetes.