Analysis of the NPHP genes in two Japanese patients with suspected sporadic juvenile or adolescent nephronophthisis.
BACKGROUND
Mutations in 3 genes (NPHP1, NPHP3 and NPHP4) have been identified in patients with juvenile or adolescent nephronophthisis (NPHP) without extrarenal involvement, mainly in patients from western countries. In this study, we analyzed mutations in the NPHP genes of 2 Japanese patients with suspected sporadic juvenile or adolescent NPHP without extrarenal involvement.


METHODS
A renal biopsy was performed in the 2 patients. Genomic DNA was prepared from peripheral blood mononuclear cells of the patients and their family members. The above NPHP genes were examined by deletion analysis or direct automated sequencing of polymerase chain reaction-amplified DNA products.


RESULTS
Histological findings in the patients were compatible with those of NPHP. In 1 patient, we identified a novel deletion mutation including about half of exons of the NPHP1 gene. In another patient, there was no mutation in the NPHP genes examined.


CONCLUSIONS
We found a novel NPHP1 deletion in 1 patient. To our knowledge, this is the second Japanese NPHP case in which genetic diagnosis was made.
Komatsuda
A
A
Third Department of Internal Medicine, Akita University School of Medicine, Akita, Japan. komatsud@med.akita-u.ac.jp
Masai
R
R
Wakui
H
H
Iwamoto
K
K
Aiba
N
N
Ohtani
H
H
Satoh
K
K
Haseyama
T
T
Imai
H
H
Nakamoto
Y
Y
Sawada
K
K
D048868:Adaptor Proteins, Signal Transducing; D000293:Adolescent; D000328:Adult; D001483:Base Sequence; D003598:Cytoskeletal Proteins; D004247:DNA / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D007564:Japan; D008565:Membrane Proteins; D009154:Mutation; D009395:Nephritis, Interstitial / Q000175:diagnosis / Q000235:genetics* / Q000473:pathology; D011506:Proteins / Q000235:genetics*; D017384:Sequence Deletion
D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; C108725:NPHP1 protein, human; C491578:NPHP4 protein, human; D011506:Proteins; D004247:DNA