Analysis of the CFTR gene in Iranian cystic fibrosis patients: identification of eight novel mutations.
BACKGROUND
Cystic fibrosis (CF) is the most common inherited disorder in Caucasian populations, with over 1400 mutations identified in the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) gene. Mutations in the CFTR gene may be also causative for CBAVD (Congenital Bilateral Absence of the Vas Deferens). The type and distribution of mutations varies widely between different countries and/or ethnic groups, and is relatively unknown in Iran. We therefore performed a comprehensive analysis of the CFTR gene in Iranian CF patients.


METHODS
69 Iranian CF patients, and 1 CBAVD patient, were analysed for mutations in the complete coding region, and its exon/intron junctions, of their CFTR genes, using different methods, such as ARMS (amplification refractory mutation system)-PCR, SSCP (single stranded conformation polymorphism) analysis, restriction enzyme digestion analysis, direct sequencing, and MLPA (Multiplex Ligation-mediated Probe Amplification).


RESULTS
CFTR mutation analysis revealed the identification of 37 mutations in 69 Iranian CF patients. Overall, 81.9% (113/138) CFTR genes derived from Iranian CF patients could be characterized for a disease-causing mutation. The CBAVD patient was found to be homozygous for the p.W1145R mutation. The most common mutations were p.F508del (DeltaF508) (18.1%), c.2183_2184delAAinsG (2183AA>G) (6.5%), p.S466X (5.8%), p.N1303K (4.3%), c.2789+5G>A (4.3%), p.G542X (3.6%), c.3120+1G>A (3.6%), p.R334W (2.9%) and c.3130delA (2.9%). These 9 types of mutant CFTR genes totaled for 52% of all CFTR genes derived from the 69 Iranian CF patients. Eight mutations, c.406-8T>C, p.A566D, c.2576delA, c.2752-1_2756delGGTGGCinsTTG, p.T1036I, p.W1145R, c.3850-24G>A, c.1342-?_1524+?del, were found for the first time in this study.


CONCLUSIONS
We identified 37 CFTR mutations in 69 well characterized Iranian CF patients, obtaining a CFTR mutation detection rate of 81.9%, the highest detection rate obtained in the Iranian population so far. These findings will assist in genetic counseling, prenatal diagnosis and future screening of CF in Iran.
Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Reza
R
Alibakhshi
Roya
R
Kianishirazi
Jean-Jacques
JJ
Cassiman
Mahdi
M
Zamani
Harry
H
Cuppens
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000453:epidemiology / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics*; D004247:DNA / Q000032:analysis / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D005838:Genotype; D006801:Humans; D007223:Infant; D007492:Iran / Q000453:epidemiology; D008297:Male; D009154:Mutation; D015995:Prevalence; D012189:Retrospective Studies
C505032:CFTR protein, human; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D004247:DNA