The number of patients with CF is relatively limited in Iran. Our center, as a large tertiary referral hospital, evidently provides care and services for all severe cases of pediatric CF. The pediatric outpatient clinic is linked to the hospital, where attending professors visit and refer suspected patients for admission and further work-ups. Over 10 years, 105 CF patients had been admitted. In our study population, the ratio of male to female was 1:1.
On average, patients were diagnosed in the second year of life. In another study, 64% of the children were diagnosed < 3 years of age .
Alkalosis was more prevalent in arterial blood gas analysis compared to acidosis. In a systematic review by Scurati-Manzoni et al., metabolic alkalosis was similar between subacute and chronic patient with cystic fibrosis .
Acute phase reactants were in slightly over one third of tested patients positive. It may be due to recurrent pulmonary infection in children with CF.
Most common findings in echocardiography were mild increase in pulmonary artery blood pressure and mild to moderate tricuspid regurgitation. Increased pulmonary artery blood pressure is the early sign of potential heart impairment in pediatric age group with CF .
Increased liver echogenicity was seen in 21% of children who underwent abdominal sonography. In the study by Akata et al., increased liver echogenicity was seen in 50% of children with CF . This difference may be due to disease stage and also expertise of radiologist.
Severe anemia was seen in our study. Early severe anemia may be the first sign of cystic fibrosis .
In the current study, 13.3% of the cases had sibling with CF. Positive consanguinity was reported in 50% of patients in another study from Egypt .
Several population-specific studies in Iran have detected novel mutations and polymorphisms in CFTR gene [21,22,23,24,25]. In the Mohseni et al.’s study, novel compound heterozygous missense mutation (c.3119 T>A (p.L1040H)), which was previously reported as nonsense c.3484C>T (p.R1162X) mutation, was found in exon 19 in patient screening . In the study by Alibakhshi et al., 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%) . Distribution of mutations are not consistent with other populations, which emphasizes the necessity of adopting modified sequence analysis for appropriate screening and genetic counseling programs in Iranian CF patients [26,27,28]. Furthermore, the clinical role of these variations should be considered as phenotype is related to the genotype .
Similar to our study, respiratory symptoms such as cough and pulmonary infection, steatorrhea, FTT , diarrhea , respiratory distress [31,32,33], alkalosis, and liver function abnormalities  have been reported to be frequent among Iranian CF patients. In a study from Egypt, chronic cough, failure to thrive, and steatorrhea were the most common findings . FTT was reported in all children in a study from Egypt .
Mortality rate was 45.23% among children with follow-up. In the study by Smith et al., among children with CF who admitted to pediatric intensive care unit, mortality rate was 19.1% which is significantly lower than our study .
Significant associations between serum albumin and protein with weight, height, and head circumference have been suggested . In a study by Vahedi et al., it was stated that positive family history, a consanguineous marriage, and residence in a rural area increases the rate of mortality . In addition, pseudomonas infection, number of previous admissions and the severity of pulmonary hypertension were mentioned as major determinants of mortality by Baghaie et al. .
The scarcity of CF studies in low prevalence countries such as Iran in contrast to the extent of European and American literature is not surprising. However, it would be a mistake to ignore the importance of fatal rare diseases, when effective managements can be applied. Failing to raise awareness in medical community leads to underdiagnosis or misdiagnosis, especially in a disease like CF which has diverse presentations. The population of Iran is heterogeneous and comprises of multiple ethnicities. Therefore, regional studies are encouraged to verify the spectrum of CF manifestations, investigate unknown causes of neonatal mortality more precisely, and conduct genetic testing to reveal specific CFTR mutations and their consequent outcomes and predicted survival.
It is well-know that earlier presentation is associated with severity of CF, while patients diagnosed in adulthood have milder clinical phenotypes. Thus, our findings cannot accurately represent the general status of all CF patients. Due to the limited number of patients, researcher could benefit most from national registries .