The canine copper toxicosis gene MURR1 is not implicated in the pathogenesis of Wilson disease.
BACKGROUND
It has recently been demonstrated that the Wilson disease (WD) protein directly interacts with the human homolog of the MURR1 protein in vitro and in vivo, and that this interaction is specific for the copper transporter. The aim of the present study was to clarify the role of MURR1 in the pathogenesis of WD as well as in other WD-like disorders of hepatic copper metabolism of unknown origin.


METHODS
Using the single-strand conformation polymorphism (SSCP) method followed by sequencing, we analyzed the 5' untranslated region (UTR) and three exons of the MURR1 gene in three groups of patients: 19 WD: patients in whom no mutations were detected in the ATP7B gene, 53 WD: patients in whom only one mutation in the ATP7B gene was found, and 34 patients in whom clinical and laboratory data suggested a WD-like disorder of hepatic copper metabolism of unknown origin.


RESULTS
We detected in these patients six rare nucleotide substitutions, namely one splice-site consensus sequence and one missense and four silent nucleotide substitutions. All substitutions except one were found in the heterozygous state. No difference in the frequencies of the various substitutions was observed between patients and controls.


CONCLUSIONS
These data suggest that the MURR1 gene and its protein product are unlikely to play a primary role in the pathogenesis of Wilson disease. More extensive studies with larger numbers of clinically homogeneous patients should be carried out to establish whether nucleotide alterations in the MURR1 gene may have a role in causing WD or WD-like disorders or act as modifying factors in the phenotype variability in WD.
Lovicu
Mario
M
Institute of Neurogenetics and Neuropharmacology, CNR-Cagliari, Cagliari, Italy.
Dessì
Valeria
V
Lepori
Maria Barbara
MB
Zappu
Antonietta
A
Zancan
Lucia
L
Giacchino
Raffaella
R
Marazzi
Maria Grazia
MG
Iorio
Raffaele
R
Vegnente
Angela
A
Vajro
Pietro
P
Maggiore
Giuseppe
G
Marcellini
Matilde
M
Barbera
Cristiana
C
Kostic
Vladimir
V
Farci
Anna Maria Giulia
AM
Solinas
Antonello
A
Altuntas
Buket
B
Yuce
Aysel
A
Kocak
Nurten
N
Tsezou
Aspasia
A
De Virgiliis
Stefano
S
Cao
Antonio
A
Loudianos
Georgios
G
D048868:Adaptor Proteins, Signal Transducing; D000251:Adenosine Triphosphatases / Q000235:genetics*; D002352:Carrier Proteins; D027682:Cation Transport Proteins / Q000235:genetics*; D003300:Copper; D000073840:Copper-Transporting ATPases; D006527:Hepatolenticular Degeneration / Q000235:genetics*; D006801:Humans; D009154:Mutation; D011506:Proteins / Q000235:genetics*
D048868:Adaptor Proteins, Signal Transducing; C480519:COMMD1 protein, human; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D011506:Proteins; D003300:Copper; D000251:Adenosine Triphosphatases; C000612464:ATP7B protein, human; D000073840:Copper-Transporting ATPases