0000000000125222
AUTHOR
D.b. Wildenauer
Evidence against linkage of schizophrenia to chromosome 5q11-q13 markers in systematically ascertained families.
Ten pedigrees systematically ascertained in Germany were tested for linkage to chromosome 5q11-q13. In order to replicate the previous report by Sherrington et al (1988), families with a bipolar family member were omitted from the lod score calculations, all diagnoses were based upon Research Diagnostic Criteria, and four different models of the affection status were calculated, including the model for which Sherrington et al calculated the highest lod scores. None of the families investigated showed a positive lod score. Using multipoint linkage analyses, we were able to exclude the region for which a positive linkage has been reported.
Gegenwärtiger Stand der Kopplungsuntersuchungen bei Schizophrenie
Fur schizophrene Erkrankungen besteht ein deutlich erhohtes genetisches Risiko, belegt durch Familien-, Zwillings- und Adoptionsstudien [1]. Die Konkordanzrate bei eineiigen Zwillingen betragt etwa 50%, ein im Vergleich zu zweieiigen Zwillingen etwa 3fach erhohtes Erkrankungsrisiko [1]. Ein einfacher Mendelscher Erbgang mit einem einzigen verantwortlichen Genort ist jedoch nicht nachweisbar. Schizophrene Erkrankungen gehoren wie zum Beispiel auch Diabetes, Bluthochdruck, Krebserkrankungen, zu den komplexen genetischen Erkrankungen mit polygener, bzw. multifaktorieller Vererbung.
Untersuchungen zur Kopplung zwischen Schizophrenie und der pseudoautosomalen Region
Fur die Suche nach Genorten fur genetisch determinierte Erkrankungen mit Hilfe von Kopplungsanalysen werden zwei Strategien angewandt: 1. das systematische Absuchen des Genoms auf Kopplung von Genort mit Marker mit Hilfe von DNA-Markern (RFLP, Short Tandem Repeats) in regelmasigen Abstanden, 2. die Verwendung von DNA-Markern zur Kopplungsanalyse in Kandidatengenregionen, fur die ein Zusammenhang mit der Erkrankung angenommen wird, bei psychiatrischen Erkrankungen, z. B. Genorte fur Enzyme, Rezeptoren, Transporter fur Neurotransmitter.
Potential linkage for schizophrenia on chromosome 22q12-q13: a replication study.
In an attempt to replicate a potential linkage on chromosome 22q12-q13.1 reported by Pulver et al. [1994: Am J Med Genet 54:36–43], we have analyzed 4 microsatellite markers which span this chromosomal region, including the IL2RB locus, for linkage with schizophrenia in 30 families from Israel and Germany. Linkage analysis by pairwise lod score analysis as well as by multipoint analysis did not provide evidence for a single major gene locus. However, a lod score of Zmax = 0.612 was obtained for a dominant model of inheritance with the marker D22S304 at recombination fraction 0.2 by pairwise analysis. In addition, using a non-parametric method, sib pair analysis, a P value of 0.068 correspon…
Evaluation of a susceptibility gene for schizophrenia on chromosome 6p by multipoint affected sib-pair linkage analysis
The influence of genetic factors in schizophrenia has been convincingly demonstrated by family, twin and adoption studies, but the mode of transmission remains uncertain. The reported pattern of recurrence risks suggests a set of interacting loci. Based on prior evidence for linkage on chromosome 6p (K. Kendler, pers. comm.), we have scanned the short arm of chromosome 6 in 54 families for loci predisposing to schizophrenia, using 25 microsatellite markers spanning 60 centiMorgans (cM). Allele sharing identity by descent was examined in affected sib-pairs from these families, followed by multipoint sib-pair linkage analysis. Positive lod scores were obtained over a wide region (D6S470 to D6…