Exclusion of the candidate genes ACE and Bcl-2 for six families with nephronophthisis not linked to the NPH1 locus.
BACKGROUND
Nephronophthisis (NPH) is an autosomal recessively transmitted kidney disease, characterized by cyst formation at the cortico-medullary junction, and a sclerosing tubulointerstitial nephropathy. Juvenile nephronophthisis (NPH1) is the most common genetic cause of renal failure in children and maps to chromosome 2q12-q13. The responsible gene NPHP1 has been identified and encodes for nephrocystin. Not all families with NPH demonstrate linkage to that locus.


METHODS
We studied six families with NPH without linkage to the NPH1 locus. In order to attempt identification of a new causative gene, the candidate genes ACE (angiotensin converting enzyme) and Bcl-2 (B cell leukaemia/lymphoma 2 gene) originating from mouse models, were examined. For the six families highly polymorphic microsatellites covering the whole candidate gene regions were haplotyped and linkage analysis was performed.


RESULTS
Haplotype analyses of all families examined were incompatible with linkage of the disease status to ACE or Bcl-2. Linkage analysis excluded both candidate gene regions with a LOD-score of < -2.


CONCLUSIONS
This study excluded the candidate genes ACE and Bcl-2 for NPH. Additional linkage studies need to be performed in order to identify further genes responsible for nephronophthisis.
Omran
H
H
University Children's Hospital Freiberg, Germany.
Häffner
K
K
Vollmer
M
M
Pigulla
J
J
Wagner
G
G
Caridi
G
G
Hildebrandt
F
F
D000293:Adolescent; D000328:Adult; D029681:Arabidopsis Proteins; D002648:Child; D002874:Chromosome Mapping; D019254:Genes, bcl-2; D008040:Genetic Linkage / Q000235:genetics*; D006801:Humans; D008126:Lod Score; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics*; D017044:Polycystic Kidney, Autosomal Recessive / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases
D029681:Arabidopsis Proteins; D010750:Phosphoproteins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D007703:Peptidyl-Dipeptidase A