Polycystic liver disease is genetically heterogeneous: clinical and linkage studies in eight Finnish families.
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.
Tahvanainen
Pia
P
Department of Human Molecular Genetics, National Public Health Institute, Mannerheimintie 166, 00300 Helsinki, Finland.
Tahvanainen
Esa
E
Reijonen
Hanna
H
Halme
Leena
L
Kääriäinen
Helena
H
Höckerstedt
Krister
K
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