Progranulin gene variability influences the risk for bipolar I disorder, but not bipolar II disorder.
OBJECTIVE
Recent data have shown that genetic variability in the progranulin (GRN) gene may contribute to the susceptibility to developing bipolar disorder (BD). However, in regard to patients with BD, no information is available on the role of genetic variability and plasma progranulin levels in different types of this disorder.


METHODS
In this study, we performed an association analysis of GRN in an Italian population consisting of 134 patients with BD and 232 controls to evaluate progranulin plasma levels.


RESULTS
The presence of the polymorphic variant of the rs5848 single nucleotide polymorphism is protective for the development of bipolar I disorder (BD-I) (odds ratio = 0.55, 95% confidence interval: 0.33-0.93; p = 0.024) but not bipolar II disorder (BD-II) (p > 0.05). In addition, plasma progranulin levels are significantly decreased in BD [mean ± standard deviation (SD) 112 ± 35 versus 183 ± 93 ng/mL in controls; p < 0.001].


CONCLUSIONS
Regarding the influence of GRN variability on BD susceptibility, the predisposing genetic background differs between BD-I and BD-II, possibly implying that pathogenic mechanisms differ between the two subtypes of BD.
Neurology Unit, Department of Pathophysiology and Transplantation, University of Milan, Fondazione Cà Granda, IRCCS Ospedale Policlinico, Milan, Italy.
Daniela
D
Galimberti
Cecilia
C
Prunas
Riccardo A
RA
Paoli
Bernardo
B
Dell'Osso
Chiara
C
Fenoglio
Chiara
C
Villa
Carlotta
C
Palazzo
Michela
M
Cigliobianco
Giulia
G
Camuri
Maria
M
Serpente
Elio
E
Scarpini
A Carlo
AC
Altamura
D000328:Adult; D000368:Aged; D001714:Bipolar Disorder / Q000097:blood / Q000145:classification / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000097:blood / Q000235:genetics*; D007558:Italy; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D000077153:Progranulins; D055815:Young Adult
C492314:GRN protein, human; D036341:Intercellular Signaling Peptides and Proteins; D000077153:Progranulins
bipolar I disorder; bipolar II disorder; genetics; polymorphism; progranulin; risk factor; single nucleotide polymorphism