Objective: The aim of our study was to evaluate the clinical features, to define the frequency of mutation type, to assess genotype-phenotype correlation and the response to colchicine in childhood-onset Familial Mediterranean fever (FMF) in Lebanon. Methods: The characteristics of 550 children, presenting with FMF symptoms between January 2003 and January 2013 and having a positive Mediterranean fever gene ( MEFV gene) mutation, were prospectively investigated. The clinical and genetic characteristics as well as the response to colchicine and its side effects were studied in 321 FMF children. The mutations were correlated with clinical presentation and disease severity. Results: Out of the 321 patients (183 males and 138 females), abdominal pain was the most common presenting feature documented in 84.7%. Mutational analysis detected simple heterozygotes, compound heterozygotes and homozygotes in 56.4%, 30.9% and 11.2% patients respectively. The most frequent mutation was M694V (37.2%), followed by E148Q mutation (27.4%). 71% patients received colchicine therapy; only 33.3% of them showed complete response. Genotype-phenotype correlation showed that M694V followed by E148Q was associated with moderate to severe disease form (71.6% and 62.7% respectively, P = 0.005). There was no association between mutation type and colchicine response. Conclusion: The most important features were the predominance of the M694V and E148Q. The M694V subgroup, followed by E148Q subgroup had a high disease severity score. Our data indicate an enhanced expression of the disease with E148Q mutation.
Familial Mediterranean fever (FMF) is the most frequent periodic syndrome characterized by self-limited recurrent attacks of fever and serositis. It is an autosomal-recessive disorder that predominantly affects people from the Mediterranean region, including Sephardic Jews, Turks, Armenians, and Arabs [
Five founding mutations M694V, V726A, M680I, M694I (in exon 10), and E148Q (in exon 2) are the most common MEFV mutations [
FMF is diagnosed mainly by clinical criteria based on Tel Hashomer criteria for the diagnosis of FMF [
There are limited data regarding the features of FMF in Lebanon, particularly among children.
The objectives of the present study are as follows: i) to review clinical and demographic features of patients with childhood-onset FMF in Lebanon, ii) to evaluate the frequency of most common mutations of FMF gene, iii) to investigate whether there is phenotype-genotype correlation in this population, and iv) to identify any adverse effects of colchicine in pediatric patients with FMF.
The pediatric cohort study group included five hundred fifty FMF Lebanese children with positive MEFV gene mutation. Patients included in the study aged 18 years or younger and referred with FMF symptoms, from various pediatric clinics to the Laboratory Department of genetic testing at Saint-Josef University, between January 2003 and January 2013, were included in the study. All of them had at least one MEFV gene mutation. The study was approved by the Institutional Review Board at Makassed General Hospital, Beirut, Lebanon, and all children with their caregivers gave informed consent to the study.
The criteria to include patients were: 1) age at FMF diagnosis ≤ 18 years, 2) with at least one MEFV gene mutation, 3) presenting with short attacks of fever at varying intervals or painful sensation in the abdomen, chest and joint or with skin manifestations, with absence of any pathological finding capable in itself explaining the clinical picture and 4) being of Lebanese nationality.
The demographic and clinical characteristics, results of MEFV gene mutation analysis were recorded and analyzed. Baseline characteristics including age, gender, date of birth, country of origin, religion, parental consanguinity, family history of FMF or renal amyloidosis, affected relatives with FMF, age of onset of disease and age at diagnosis were all determined. Clinical manifestations including features such as duration and frequency of fever, abdominal pain, arthralgia, chest pain, headache, vomiting, diarrhea, constipation, myalgia, cutaneous manifestations, liver involvement, number of the attacks, previous hospitalizations and surgeries done prior to diagnosis were also determined for the study.
The efficiency of colchicine in suppressing the attacks, including colchicine doses, possible side effects and number of FMF attacks after colchicine treatment, were all evaluated. Response to colchicine treatment was
Major Criteria |
---|
1. Recurrent febrile episodes accompanied by peritonitis, synovitis or pleuritis 2. Amyloidosis of the AA type without predisposing disease 3. Favorable response to continuous colchicine treatment |
Minor Criteria |
1. Recurrent febrile episodes 2. Erysipelas-like erythema 3. FMF in a first-degree relative |
Definite diagnosis: 2 major or 1 major and 2 minor criteria Probable diagnosis: 1 major and 1 minor criteria |
evaluated as complete response defined as complete control of the clinical manifestations, incomplete (decline > 50% in the frequency of attacks) and unresponsive (no improvement in frequency attack and/or severity of the disease despite colchicine treatment).
To assess the severity of the disease, we used a disease severity score adapted by Ozen et al. A total score of 3-5 is accepted as mild, 6-9 is moderate and above 9 is severe disease [
For specified evaluation of phenotype-genotype correlation, the patients underwent three different types of classifications. First, the patients were classified according to M694V gene mutation into three groups: Group I, M694V/M694V; Group II, M694V/other; and Group III, other/other. Second, the patients were classified according to the genotypes with one or two mutations of M694V, E148Q, V726A group and others (other mutations).
The two classifications were compared in terms of age of onset, age at diagnosis, time interval between the disease onset and diagnosis, fever, abdominal pain, arthralgia, chest pain, severity of the disease and response to colchicine.
Molecular diagnosis of FMF was carried out in the Laboratory Department for genetic testing at Saint-Josef University. 3 ml of blood was withdrawn from each patient into tubes containing ethylenediamine-tetraacetic acid. DNA was extracted using a commercial kit; sequencing was performed for the analysis of the MEFV gene. MEFV gene at exons 2, 3, 5, 10 was screened for the causative mutations, approximately for more than 30 mutations (
Parameter | Features | Score |
---|---|---|
Age of onset (years) | 11 - 20 | 2 |
6 - 10 | 3 | |
<6 | 4 | |
Number of attacks per month | <1 | 1 |
1 - 2 | 2 | |
>2 | 3 | |
Arthritis | Acute | 2 |
Protracted | 3 | |
Erysipelas-like erythema | 2 | |
Amyloidosis | 3. | 3 |
Dose of colchicine | ||
Less than appropriate* dose | 0 | |
Appropriate dose | 1 | |
More than appropriate dose | 2 |
A total score of 3 - 5 is accepted as mild, 6 - 9 is moderate and >9 is severe disease. *Starting colchicine doses for children with familial Mediterranean fever: <5 years, 0.5 mg/day; 5 - 10 years, 1.0 mg/day; >10 years, 1.5 mg/day.
All the analyses were performed using SPSS version 19. The data were presented as mean ± SD or number (percent). One Way ANOVA and Chi-square test were utilized to assess significance differences among the groups. Nonparametric test (goodness of fit) was used to compare the results of this study with those of other studies. P-value < 0.05 was considered significant.
The study population was composed of a total of 550 FMF Lebanese children; all were included in the MEFV mutational analysis. However, only 321 children with FMF were included in the analysis of demographic and clinical characteristics, use of colchicine and phenotype-genotype correlation. The remaining 229 children with FMF were excluded from the above analysis due to lack of clinical information or incomplete chart data.
Genetic data:
Clinical data: Of the 321 children with FMF, 183 (57%) were males and 138 (43%) were females (male/ female ratio 1.1:1).The mean age of onset 4.61 ± 3.76 years (range from 1 month to 16 years of age).The mean age at diagnosis onset was 7.08 ± 4.24 years. The mean delay in diagnosis of FMF in Lebanese children was 2.63 ± 2.08 years. When the data were analyzed with regard to child’s parental region of origin and religion, 44.9% had originated from South Lebanon, followed by North Lebanon (25.5%) and then from the capital Beirut (19.3%). Regarding the religion, it was noticed that 83.2% of FMF children were Moslems and 16.2% were Christians. Consanguinity rate was 11.5% in the families of the children with FMF. Family history of FMF was noticed in 40.8%. Family history of renal amyloidosis was noted only in 2 (0.6%) children with FMF.
The main clinical characteristics of the patients were as follow : Abdominal pain was the most common form of presentation (84.7%), followed by fever (78.2%). 40.8% of children with FMF had attack frequency of one or two attacks per month, and most of the patients (94.7%) had attack duration less than 5 days. Eight patients (2.5%) underwent appendectomy prior to the diagnosis. 144 patients with FMF (44.9%) were hospitalized, and in most cases (88.2%), 1-3 times prior the diagnosis of FMF. None of the 321 patients studied developed renal amyloidosis over the period of follow up. The distribution of FMF disease severity score was as follows: mild disease (a score = 3 - 5) in 132 (41.1%), moderate (a score = 6 - 9) in 187 (58.3%) and severe (a score > 9) in 2 (0.6%) (
Response to colchicine treatment
Of the 321 patients, 228 (71%) patients were treated with colchicine. Regarding the colchicine dosage for age, we found that 148 (64.9%) patients were receiving colchicine dose less than appropriate for age, and only 68 (29.8%) patients were receiving the appropriate dose for age, whereas, 12 (5.3%) patients were receiving colchi-
Mutations | Genotype | Patients, n (%) |
---|---|---|
Homozygotes | M694V/M694V M694I/M694I E148Q/E148Q | 62 (11.2%) 28 13 9 |
V726A/V726A M680I/M680I R761H/R761H | 9 2 1 | |
Compound heterozygotes | 170 (30.9%) | |
M694V/V726A E148Q/M694V M694V/M694I M694I/V726A M680I/V726A M694V/R761H E148Q/M694I E148Q/V726A M680I/M694V M694I/R761H M694V/E148Q P369S/R408Q E474K/R761H E167D/F479L Others | 35 12 12 11 10 8 8 8 7 6 3 3 3 3 41 | |
Simple heterozygotes | 310 (56.4%) | |
E148Q/- M694V/- V726A/- M694I/- A744S/- R761H/- A289V/- I259V/- Others | 92 68 52 32 21 9 7 4 25 | |
Complex heterozygotes | 8 (1.5%) | |
P369S/R408Q/A457V V726Z/R7261H/E148Q P369S/R408Q/R761H E148Q/E148V/M694I E167D/F479L/V726A I692del/E148Q/E148V P369S/R408S/V726A | 2 1 1 1 1 1 1 | |
Total | 550 |
Signs and symptoms | Patients, n (%) (n = 321) |
---|---|
Abdominal pain | 272 (84.7%) |
Fever | 251 (78.2%) |
Arthralgia | 138 (43%) |
Chest pain | 98 (30.5%) |
Vomiting Constipation Diarrhea Headache | 49 (15.3%) 43 (13.4%) 20 (6.2%) 9 (2.8%) |
---|---|
Myalgia Cutaneous manifestations | 8 (2.5%) 30 (9.3%) |
Buccal or genital aphthosis | 18 (60%) |
Erysipelas like rash | 1 (3.3%) |
Recurrent pruritic rash | 4 (13.3%) |
Angioedema or urticaria | 1 (3.3%) |
Cutaneous photosensitivity | 6 (20%) |
Episode attack | |
<1 attack per month | 100 (31.2%) |
1 - 2 attacks per month | 131 (40.8%) |
>2 attacks per month | 90 (28%) |
Duration | |
≤5 days | 304 (94.7%) |
>5 days | 17 (5.3%) |
Appendectomy | 8 (2.5%) |
Number of hospital admission before diagnosis | 144 (44.9%) |
1 - 3 hospitalization | 127 (88.2%) |
>3 hospitalization | 17 (11.8%) |
Disease severity score Mild Moderate Severe | 132 (41.1%) 187 (58.3%) 2 (0.6%) |
cine dose more than required for age. 76 (33.3%) patients on colchicine responded with complete remission, whereas, 119 (52.2%) patients showed incomplete response and 33 (14.5%) patients did not show any response to colchicine.
Colchicine was well tolerated by most of our patients. Only 64 (28%) of FMF patients treated with colchicine developed adverse events. The most reported adverse effects was diarrhea in 28 (12.3%) FMF patients treated with colchicine, headache in 17 (7.5%), vomiting in 8 (3.5%), rash in 5 (2.2%), muscle weakness in 4 (1.8%) and both thrombocytopenia and leucopenia were observed in one (0.4%) patient only.
Genotype-phenotype correlation
While the patients were divided into four subgroups according to genotypes of one or two mutations of M694V, E148Q, V726A and others, fever and chest pain were found to be more frequent in M694V and V726A subgroups when compared to other subgroups (P = 0.003 and P = 0.007 respectively).The M694V subgroup, followed by E148Q subgroup had higher disease severity score (moderate and severe), compared to other subgroups (P = 0.005). There was no statistically significant difference among the studied groups concerning response to colchicine treatment (
M694V/M694V (n = 17) | M694V/Other (n = 72) | Other/Other (n = 232) | P-value | |
---|---|---|---|---|
Age of onset (years), mean ± SD | 3.9 ± 2.7 | 3.7 ± 3.5 | 4.9 ± 3.7 | 0.041 |
Age at diagnosis (years), mean ± SD | 6.4 ± 3.7 | 6.618 ± 4.4 | 7.2 ± 4.2 | 0.426 |
Delay in diagnosis (years), mean ± SD | 2.5 ± 2.3 | 2.9 ± 2 | 2.5 ± 2 | 0.592 |
Abdominal pain | 15 (88.2%) | 61 (84.7%) | 196 (84.5%) | 0.917 |
Fever | 15 (88.2%) | 64 (88.9%) | 172 (74.1%) | 0.018 |
Chest pain | 7 (41.2%) | 29 (40.3%) | 62 (26.7%) | 0.057 |
Arthralgia | 12 (70.6%) | 34 (47.2%) | 92 (39.7%) | 0.032 |
>3 hospitalizations prior to diagnosis | 3 (17.6%) | 1 (1.4%) | 13 (5.6%) | 0.015 |
Response to colchicine | 0.069 | |||
No response | 2 (11.8%) | 7 (9.7%) | 47 (20.3%) | |
Incomplete response | 11 (64.7%) | 36 (50%) | 90 (38.8%) | |
Complete response | 4 (23.5%) | 9 (40.3%) | 95 (40.9%) | |
Severity score | 0.008 | |||
Mild | 3 (17.6%) | 22 (30.5%) | 107 (46.1%) | |
Moderate and severe | 14 (82.4%) | 50 (69.5%) | 125 (53.9%) |
M694V* (n = 89) | E148Q** (n = 75) | V726A*** (n = 68) | Other**** (n = 89) | P-value | |
---|---|---|---|---|---|
Age of onset (years), mean ± SD | 3.7 ± 3.4 | 4.7 ± 3.4 | 5.2 ± 4 | 4.8 ± 3.6 | 0.068 |
Age at diagnosis (years), mean ± SD | 6.5 ± 4.2 | 7.0 ± 3.8 | 7.8 ± 4.6 | 7.0 ± 4 | 0.30 |
Delay in diagnosis (years), mean ± SD | 2.8 ± 2 | 2.3 ± 2 | 2.7 ± 2.5 | 2.5 ± 2 | 0.69 |
Abdominal pain | 76 (85.4%) | 64 (85.3%) | 61 (89.7%) | 71 (79.8%) | 0.38 |
Fever | 79 (88.8%) | 51 (68%) | 57 (83.8%) | 64 (71.9%) | 0.003 |
Chest pain | 36 (40.4%) | 13 (17.3%) | 25 (36.8%) | 24 (27%) | 0.007 |
Arthralgia | 46 (51.7%) | 31 (41.3%) | 25 (36.8%) | 36 (40.4%) | 0.24 |
>3 hospitalizations prior to diagnosis | 4 (4.5%) | 3 (4%) | 4 (5.9%) | 6 (6.7%) | 0.78 |
Response to colchicine | 0.08 | ||||
No response | 9 (10.1%) | 11 (14.6%) | 13 (19.1%) | 23 (25.8%) | |
Incomplete response | 47 (52.8%) | 29 (38.7%) | 29 (42.7%) | 32 (36%) | |
Complete response | 33 (37.1%) | 35 (46.7%) | 26 (38.2%) | 34 (38.2%) | |
Severity score | 0.005 | ||||
Mild | 25 (28.1%) | 28 (37.3%) | 32 (47.1%) | 47 (52.8%) | |
Moderate and severe | 64 (71.9%) | 47 (62.7%) | 36 (52.9%) | 42 (47.2%) |
*M694V/M694V, M694V/Other or M694V/; **E148Q/E148Q, E148Q/Other or E148Q/; ***V726A/V726A, V726A/Other or V726A/; SD: standard deviation.
The data in this study was obtained from the Laboratory Department of genetic testing at the Saint-Josef University that nearly all FMF suspected children in Lebanon were referred. Our study is the first that exclusively examine FMF children with positive MEFV mutation in Lebanon.
In our study, 56.4% of FMF children were simple heterozygous. The possible explanation of this high rate of simple heterozyosity that give rise to FMF phenotype is the presence of one or more modifying alleles in other related genes, or other environmental factors. More recent study found a higher frequency of carriers for highly penetrant FMF mutations among patients with systemic inflammatory response syndrome and sepsis [
In our study, M694V was detected as the most common mutation (37.2%) which is similar to almost all population except for Iraqis who witness a total absence of this allele [
Most of the studies reported that FMF affect both sexes equally, with male or female predominance was also reported in different series [
The onset of clinical manifestations in FMF occurs before 5 years of age in 63% - 68% of cases and before 20 years of age in 90% of cases. However, the onset may be as early as 6 months of age [
Although fever is the symptom for which the disease is named, and although fever has been seen in 100% of patients in some reports, an incidence of only 80-85% has been observed in some studies [
In our study, 8 of 321(2.5%) patients underwent appendectomy, which was less than that reported by Talaat et al, who had 4 of 70 (5.7%) FMF patients underwent appendectomy [
The percentage of colchicine non responders in this study (14.5%) was higher than that reported in the other ethnic groups (5% - 10%) [
Studies conducted after the discovery of the gene (MEFV) related to FMF focused particularly on phenotypic- genotypic associations of this clinically heterogenic disease. Although results of these studies were sometimes confusing, they clarified that phenotypic-genotypic association of FMF is multifactorial and fairly complex. Studies pointed out those patients who are carriers of the M694V mutation have more severe phenotypic characteristics [
When comparing the groups according to different genotypes, moderate to severe disease was observed in M694V subgroup then followed by E148Q subgroup (P = 0.02),which was different than that reported in other studies that E148Q tend to have a mild clinical course [
In our study, there was no correlation between the response to colchicine and the different genotypes, however Oguz et al., established the relationship between M694V homozygosity and the unresponsiveness to colchicine treatment [
Since none of our patients developed amyloidosis, we could not conclude any association between M694V and the development of amyloidosis.
In conclusion, our study was the first to demonstrate the clinical features of childhood-onset Familial Mediterranean Fever (FMF), to define the frequency of mutation type, to assess genotype-phenotype correlation and the response to colchicine in FMF Lebanese children. This study established new aspects related to the spectrum of MEFV mutations and confirmed the mutational heterogeneity of FMF in Lebanon. The genotype distribution of FMF children in Lebanon was found to be different from other countries. The M694V is the most common mutation and seems to have an association with a more severe course and an earlier onset of the disease. On the other hand, E148Q was the second most common frequent mutation, and showed a relatively moderate disease severity.
Our study supports the mounting evidence that single heterozygotes may be associated with more severe FMF symptoms.
Sirine Mneimneh,Amal Naous,Ziad Naja,Zeina Naja,Ahmad Salaheddine Naja,Andre Megarbane,Mariam Rajab, (2016) Familial Mediterranean Fever: Clinical and Genetic Characteristics among Lebanese Pediatric Population. Open Journal of Rheumatology and Autoimmune Diseases,06,63-73. doi: 10.4236/ojra.2016.63011