R229Q polymorphism of NPHS2 gene in patients with late-onset steroid-resistance nephrotic syndrome: a preliminary study.
BACKGROUND
Depending on the response to standard steroid therapy, nephrotic syndrome it is classified to steroid-sensitive and steroid-resistant nephrotic syndrome (SRNS). Mutations in several genes including NPHS2 have been implicated in SRNS. Gene R229Q polymorphism (p.R229Q) of NPHS2 is associated with adolescent- or adult-onset SRNS in European and South American populations. We investigated this polymorphism among a group of Iranian-Azeri patients with primary SRNS.


METHODS
All participants had the primary late-onset form of focal segmental glomerulosclerosis (FSGS) and their clinical feature was steroid unresponsiveness. They were compared with a group of age- and sex-matched individuals without any renal disease for NPHS2 gene as controls. The R229Q polymorphism (p.R229Q) was investigated in the case and control groups.


RESULTS
A total of 25 patients (mean age, 26.6 +/- 8.0 years) with primary FSGS and 35 controls (mean age, 26.0 +/- 8.7 years) were studied. Serum creatinine of patients and their 24-hour protein excretion at the time of study were 2.4 +/- 1.94 mg/dL and 2830 +/- 981 mg/dL, respectively. Molecular study showed no p.R229Q polymorphism, neither in patients nor in controls.


CONCLUSIONS
In this preliminary study, we showed that NPHS2 gene p.R229Q polymorphism does not present in Iranian-Azeri population with SRNS. Larger studies are needed to confirm our results and other mutated genes should also be considered in these patients.
Chronic Kidney Disease Research Center and Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. ardalan34@yaho.com.
Nikou
N
Fotouhi
Mohammadreza
M
Ardalan
Mortaza
M
Jabbarpour Bonyadi
Reza
R
Abdolmohammadi
Amir
A
Kamalifar
Hamid
H
Nasri
Behzad
B
Einollahi
D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D005260:Female; D005923:Glomerulosclerosis, Focal Segmental / Q000150:complications; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007492:Iran; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D009404:Nephrotic Syndrome / Q000150:complications / Q000151:congenital* / Q000208:ethnology / Q000235:genetics; D011110:Polymorphism, Genetic; D011507:Proteinuria / Q000378:metabolism; D055815:Young Adult
D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C407223:NPHS2 protein; D003404:Creatinine