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 familial mediterranean fever ( fmf ) is an autosomal recessive hereditary autoinflammatory disease , which primarily affects several ethnic groups originating in the mediterranean basin including jews ( mainly non - ashkenazi ) , armenians , turks , arabs , and less commonly greeks and italians .
however , in recent years , more and more cases have been reported in countries out of this area , such as the usa and japan . 
 
 caused by mutations in mefv gene ,
fmf is a disorder characterized by lifelong recurrent and self - limited episodes of paroxysmal attacks of fever and serosal inflammation , resulting in pain in the abdomen , chest , joints and muscles . 
 

most patients with fmf experience their first attack in early childhood . in 65 percent of cases ,
the initial attack occurs before the age of 10 , and in 90 percent before the age of 20 ; while it rarely occurs beyond the age of 40 years . in each case
, the disease may present differently or may change its course over the patient s lifetime .
similarly , different manifestations of fmf have been observed among populations of various ethnic origins .
each attack lasts 1 - 4 days on average and resolves spontaneously . 
 
 in almost all patients the attack
is preceded by a prodromal period with symptoms mostly including myalgia , arthralgia , headache , nausea , vomiting , constipation , diarrhea , dyspnea , low back pain , asthenia and anxiety . 
 

the typical manifestations of fmf include fever , peritonitis , pleuritis , arthritis , and erysipelas - like erythema .
one of the devastating complications of fmf is the development of amyloidosis , which mainly affects the kidneys but may involve other organs as well . 
 

it is reported that late onset fmf ( over 40 years of age ) may have a milder clinical presentation . 
 

although accompanied with some side effects , long - term daily colchicine is the mainstay of therapy for the disease .
treatment results in complete remission or marked reduction in the frequency , duration , and severity of attacks in most patients and prevents amyloidosis . 
 

the 15 to 20 million azeri turks living in northwestern of iran are ethnically closely related to turkish people living in turkey .
there are a few reports of fmf in iran and based on our knowledge there are no report about the adult - onset type .
the purpose of this study was to review clinical presentation , demographic characteristics and treatment outcome of adult patients with fmf in northwest of iran . 


 in this cross - sectional study , adult patients ( first attack at the age of > 20 years ) with a diagnosis of fmf who referred to gastroenterology and rheumatology clinics of ardebil university of medical science ( situated in north west of iran ) over the period of 2004 - 2009 were enrolled .
all patients were of azeri turk origin and diagnosis was based on clinical criteria for fmf ( table 1 ) .
the study was approved by the research and ethical committee of ardebil university of medical science and an informed consent was obtained from all patients . 
 

main demographic and clinical data including age , sex , age at onset of disease , age at diagnosis , duration of the attacks , frequency of the attacks , attack symptoms and family history of fmf were recorded . 
 

colchicine ( 1 mg per day ) was started for all patients at the time of diagnosis .
all patients were followed during the study for drug adherence , adverse drug reactions and the course of the disease .
laboratory tests ( cbc , bun , creatinin and urine analysis ) were checked at the beginning and during the follow - up period . 
 

response to colchicine was defined as complete ( no attack ) or partial ( > 50% decrease in frequency of attacks ) and unresponsive according to clinical condition .
good compliance with treatment was defined by adherence to colchicine more than 95% of the time . 
 

mean  sd were calculated for quantitative variables , and frequencies and percentages were reported to describe qualitative variables . 


 main demographic and clinical data including age , sex , age at onset of disease , age at diagnosis , duration of the attacks , frequency of the attacks , attack symptoms and family history of fmf were recorded . 
 

colchicine ( 1 mg per day ) was started for all patients at the time of diagnosis .
all patients were followed during the study for drug adherence , adverse drug reactions and the course of the disease .
laboratory tests ( cbc , bun , creatinin and urine analysis ) were checked at the beginning and during the follow - up period . 


 response to colchicine was defined as complete ( no attack ) or partial ( > 50% decrease in frequency of attacks ) and unresponsive according to clinical condition .
good compliance with treatment was defined by adherence to colchicine more than 95% of the time . 


 data were analyzed by spss v.15 software ( chicago , il , usa ) .
mean  sd were calculated for quantitative variables , and frequencies and percentages were reported to describe qualitative variables . 


 forty - four patients ( 30 males and 14 females ) with a clinical diagnosis of fmf were included .
sd , standard deviation ; yr , year ; mo , month 
 
 eleven patients ( 25% ) had positive family history for fmf .
five patients ( 11.5% ) reported their first attack after the age of 40 , 10 ( 23.0% ) between 30 - 40 years of age and 29 ( 65.5% ) cases between 20 - 29 years of age .
all 43 patients continuing treatment responded to treatment even though low - dose colchicine ( 1 mg per day ) was administered .
response to treatment was complete in 33 ( 76.7% ) and partial in 10 ( 23.3% ) patients .
moreover , 53.5% of patients had good compliance with treatment , while other 46.5% had irregular usage of the administered drug .
all of irregular users developed recurrence of attack after a mean duration of 1.20  0.95 months .
the most common symptoms were abdominal pain and fever which occurred in 42 ( 95.5% ) , and 40 ( 91% ) of the patients , respectively .
abdominal pain was generalized in 88 % and localized in one or two quadrants in 12% of patients .
the most common misdiagnosis was acute appendicitis in 6 ( 13.6% ) patients , all of whom had undergone appendectomy .
other misdiagnoses were diverticulitis , pulmonary embolism , pancreatitis , ischemic heart disease and palindromic rheumatism , each in 1 ( 2.3% ) patient .
there was no clinical or laboratory evidence of amyloidosis at the time of diagnosis or during the follow - up period in our patients . 
 
 in one patient colchicine

 fmf usually occurs in young age ; most patients ( 90% ) begin to suffer from their first attack before 20 years of age . onset of the disease at an older age may occur but is uncommon after the age 40 . the date of onset of fmf is usually determined by history , although misinterpretation and misdiagnosis can occur .
previous studies revealed a subgroup of late or adult - onset patients with different demographic , clinical and probably genetic features . 
 
 in our patients
the mean age of first attack was 29.0  7.8 years and it occurred after the age of 40 in five patients ( 11.5% ) .
this finding is similar to the study by sayarlioglu et al . who reported that 5 patients ( 8.8% ) had their first attack after the age of 40 .
this difference is probably due to the study population , as we included only adult patients . 
 

the mean age at diagnosis in our study was 34.59.7 years that is comparable with other studies reporting a mean age of 34.2  9.5 years .
male / female ratio in our patients was about 2/1 . similarly in a turkish study , 80% of fmf patients with late onset disease were male . in another report from the northwest of iran ,
by contrast , ureten et al . declared that the majority of fmf patients were female ( female / male : 1.85 ) . 
 

the erratic nature of disease and short period of attack make it difficult to make the correct diagnosis early in the course of disease .
mean delay in diagnosis in our patients was 5.0  5.9 years , which was similar to reports by tamir et al ( 4.9  5.8 years ) and sayarlioglu et al .
( 6.0  6.6 years ) and different from the study done by ureten et al . which estimated a mean duration between disease onset and diagnosis of 9.39  8.92 years .
the diagnostic delay in patients with adult onset disease seems to be significantly less than those with early onset , nonetheless , tunca et al
. showed no significant difference in the diagnostic delay among patients with early ( before the age of 18 years ) versus late onset disease .
we considered that this differnce may be attributed to more attention of adults to new manifestations and more attention to receive a final diagnosis . 
 

a significant proportion of patients with fmf have positive family history . in our study , only 25% of patients had positive family history of fmf which is mostly similar to the prevalence rate of 23% reported in one turkish study .
this may be due to occurrence of new mutations in some populations which needs to be further evaluated . 
 

the hallmark of fmf is recurrent acute febrile attack and involvement of abdomen , chest , joints , muscles , scrotum and skin .
abdominal pain is present in about 95% of patients , and the clinical picture is that of acute peritonitis .
likewise , in our patients abdominal pain ( 95.5% ) and fever ( 91% ) were the most common clinical findings which are in accordance with most other studies .
however , tsuchiya - suzuki et al . reported that only 55% of patients suffered from abdominal symptoms .
our study depicted that 26.7% of male fmf cases had scrotal pain 50% of females had pelvic pain which is not previously mentioned by other studies . 
 

arthritis and erysipelas - like erythema were seen in 4.5% and 2.3% of our patients respectively , which is less frequent than reports in younger patients . in agreement with our findings ,
tunca et al . concluded that arthritis , arthralgia , myalgia , and erysipelas - like erythema were significantly less frequent among the adult - onset patients . 
 

amyloidosis is the most significant complication of fmf , usually affecting the kidneys and resulting in renal insufficiency . on the other hand ,
there are unexplained ethnic differences in the prevalence of amyloidosis . in untreated north - african jews , armenians , and turks
, its prevalence reaches as high as 60% or more , whereas in ashkenazi and iraqi jews , american- armenians , and arabs , it is less common .
none of our patients had clinical or laboratory evidence of amyloidosis during follow - up period , similar to a study in japan that amyloidosis was seen in only 1 of 80 patients .
this implies that late onset fmf may have a less aggressive behavior probably due to different mutation as compared to early onset disease .
earlier diagnosis and therapy with higher compliance to treatment in this group are the other probable contributing factors . 
 

misdiagnosis is common in fmf patients because the disease involves different organs and may have different clinical presentations .
consequently , diseases mistaken for fmf may be different in adults than in children , probably due to the lower prevalence or even lack of a number of diseases such as diverticulitis , pulmonary embolism and pancreatitis during childhood .
six patients ( 13.6% ) had abdominal operation with impression of acute appendicitis . in the study done by ureten
20% of patients underwent appendectomy ; most of the patients were operated before the diagnosis of fmf was made .
other misdiagnoses in our patients were diverticulitis , pulmonary embolism , pancreatitis , ischemic heart disease and palindromic rheumatism . 
 

this is similar to other studiesand indicates that response to colchicine in adult onset fmf is excellent and lower doses of colchicine may be adequate ( 1 mg per day ) .
this is the first study to describe the characteristics of iranian fmf patients whose disease started after the age of 20 years .
the most important one is the absence of genetic analysis as well as mutation studies .
lack of a reliable and complete family history to form genealogy trees of the patients is one limitation which inhibits the precise genetic analysis . 
 
 in conclusion
, our findings demonstrated that adult - onset fmf in iran is more common in males , arthritis and erysipelas - like erythema are seen less commonly , and there is a shorter delay before diagnosis , and a better treatment outcome ( favorable response even to low - dose colchicines ) .
moreover , a better tolerance of drug with a lower risk of amyloidosis is seen in adult - onset fmf patients .
however , the role of genetic or environmental factors should be evaluated and determined in future studies .
background 

 familial mediterranean fever ( fmf ) is an autosomal recessive disorder characterized by sporadic , paroxysmal attacks of fever and serosal inflammation . 
 although the disease usually begins before the age of 20 years , we aimed to evaluate the demography , clinical features and treatment outcome of familial mediterranean fever in iranian adult patients above 20 years old . 

 
 methods 

 in this cross - sectional study , adult patients ( first attack at the age of > 20 years ) with a diagnosis of fmf who referred to the gastroenterology and rheumatology clinics of ardebil university of medical science ( situated in north west of iran ) over the period of 2004 - 2009 were enrolled . 
 fmf diagnosis was based on clinical criteria . 

 
 results 

 forty four fmf patients ( 30 male and 14 female ) with the mean [  standard deviation ( sd ) ] age of first attack of 29  7.8 years were enrolled . abdominal pain ( 95.5% ) and 
 fever ( 91% ) were the most common clinical findings . 
 all of the patients had satisfactorily responded to therapy . 
 response was complete in 76.7% and partial in 23.3% of the patients . 
 there was no clinical or laboratory evidence of amyloidosis at the time of diagnosis or during follow - up . 

 
 conclusion 

 our findings demonstrated that adult - onset fmf in iran has different characteristics ( more common in males , lesser prevalence of arthritis and erysipelas - like erythema , less delay in diagnosis ) and treatment outcome ( favorable response even to low - dose colchicine ) in comparison with the previous data on early onset patients .