title: Polycystic liver disease is genetically heterogeneous: clinical and linkage studies in eight Finnish families.
abstract: OBJECTIVE
  Polycystic liver disease (PCLD), a dominantly inherited condition separate from polycystic kidney disease (PKD), has recently been found to be linked to a locus on chromosome 19p13.2-13.1 in two North American families. Our aim was to study whether there is clinical or genetic heterogeneity within PCLD families.
  
  
  METHODS
  We collected clinical data of eight Finnish PCLD families and performed both linkage analysis and an extended admixture test. We used genetic markers located on chromosome 19p13.2-13.1 and, in addition, on the three known PKD loci on chromosomes 4q21-q23 (PKD2), 6p21 (ARPKD) and 16p13.3-p13.12 (PKD1).
  
  
  RESULTS
  There were a total of 33 PCLD patients among which the severity of the disease varied greatly even within families. Seven patients had disabling symptoms requiring cyst decompression while ten patients were found only when the symptomless family members were studied by abdominal ultrasound. When genetic homogeneity was assumed, the PCLD locus on chromosome 19p13.2-13.1 was excluded but when genetic heterogeneity was allowed, five families out of seven showed linkage to that locus. All three PKD loci were excluded.
  
  
  CONCLUSIONS
  Most Finnish PCLD families are linked to chromosome 19p13.2-13.1 but there exists also a second PCLD locus yet to be found.
authors.affiliation: Department of Human Molecular Genetics, National Public Health Institute, Mannerheimintie 166, 00300 Helsinki, Finland.
authors.forename: Pia
authors.initials: P
authors.lastname: Tahvanainen
authors.forename: Esa
authors.initials: E
authors.lastname: Tahvanainen
authors.forename: Hanna
authors.initials: H
authors.lastname: Reijonen
authors.forename: Leena
authors.initials: L
authors.lastname: Halme
authors.forename: Helena
authors.initials: H
authors.lastname: Kääriäinen
authors.forename: Krister
authors.initials: K
authors.lastname: Höckerstedt
mesh_terms: D000328:Adult; D002874:Chromosome Mapping; D002888:Chromosomes, Human, Pair 19 / Q000235:genetics; D003560:Cysts / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery; D019299:Decompression, Surgical; D005260:Female; D005387:Finland; D008040:Genetic Linkage; D014644:Genetic Variation; D006801:Humans; D008107:Liver Diseases / Q000000981:diagnostic imaging / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery; D008297:Male; D010375:Pedigree; D012720:Severity of Illness Index; D014463:Ultrasonography