Table 1. Demographic and clinical characteristics of pediatric patients with familial Mediterranean fever according to genotype.
	Total (n=320)	M694V heterozygous (n=247)	  M694V/E148Q
      (n=73)	p value	
Female, n (%)	150 (46.9) 	110 (44.5)	40 (54.8)	   0.123	
Age at admission, months 	93.5 (52-139.2)	88 (51.5-132)	119 (62-180)	0.005	
Age at diagnosis, months	82 (46-127.5)	      79.5 (46-120.2)	95 (46.3–134.8)	0.317	
Age at symptom onset, months	48 (23.5-86.5)	47 (24-84)	59 (19.5-93)	0.493	
Time from symptom onset to diagnosis, months,	18 (9-36.5)	18 (10-36)	21 (6.5-40.5)	0.881	
Follow-up duration, months	31 (14.5–65)	31 (12–62)	      32 (20–80)	0.143	
Family history of FMF, n (%)	95 (29.7)	70 (28.3)	25 (34.2)	0.332	
Attack frequency (attacks/year)	8 (5–12)	10 (6–12)	6 (4–12)	0.481	
Attack duration, n (%)
   <24 h
   24-47 h
   48-72 h
   >72 h	
40 (12.5)
63 (19.7)
143 (44.8)
74 (23.2)	
25 (10.2)
48 (19.4)
112 (45.5)
62 (25.2)	
15 (20.5)
15 (20.5)
31 (42.5)
12 (16.4)	
0.076	
Fever, n (%)	240 (75.0)	 192 (77.7)	48 (65.8)	0.038	
Abdominal pain, n (%)	232 (72.5)	 180 (72.9)	52 (71.2)	0.783	
Chest pain, n (%)	      53 (16.6)	 29 (11.7)	24 (32.9) 	<0.001	
Arthralgia, n (%)	 149 (46.6)	 115 (46.6)	34 (46.6) 	0.998	
Arthritis, n (%)	2 (13.1)	35 (14.2)	7 (9.6)	0.309	
ELE, n (%)	19 (5.9)	17 (6.9)	2 (2.7)	0.263†	
ELP, n (%)	29 (9.1)	22 (8.9)	7 (9.6)	0.858	
PFMS, n (%)	5 (1.6)	5 (2.0)	0 (0.0)	0.592†	
ISSF, n (%)
   Mild
   Moderate
   Severe	
257 (80.3)
62 (19.4)
1 (0.3)	
204 (82.6)
43 (17.4)
0 (0)	
53 (72.6)
19 (26.0)
1 (1.4)	
0.035†	
Colchicine resistance, n (%)	5 (1.6)	5 (2.0)	0 (0.0)	0.592†	
Data are presented as median (IQR) or n (%).
Abbreviations: FMF, Familial Mediterranean Fever; IQR, interquartile range; ELE, erysipelas-like erythema; ELP, exertional leg pain; PFMS, protracted febrile myalgia syndrome; ISSF, International Severity Scoring System for Familial Mediterranean Fever.
† Fisher's exact test.

Table 2. Laboratory findings during attacks and attack-free periods by genotype
	Total (n=320)	M694V heterozygous (n=247)	  M694V/E148Q (n=73)	p value	
WBC during attack, cells/µL	10100 (7535–12745)	10580 (7730–12760)	8625 (7175–11815)	0.044	
CRP during attack, mg/L	64.8 (37.7–112.2)	65.0 (37.3–112.0)	64.6 (36.5–117.5)	0.943	
ESR during attack, mm/h	31 (22–42.3)	32 (21–42)	31 (26–43)	0.554	
Attack-free WBC, cells/µL	7160 (6040–8350)	7165 (5997.5–8432.5)	7140 (6070–8060)	0.474	
Attack-free CRP, mg/L	0.5 (0.5–1.6)	0.5 (0.5–1.6)	0.5 (0.5–1.65)	0.773	
Attack-free ESR, mm/h	6 (5–10)	6 (5–9)	6 (5.5–11)	0.128	
Attack-free SAA, mg/L	0.35 (0.30–0.55)	0.34 (0.29–0.55)	0.35 (0.31–0.54)	0.686	
Data are presented as median (IQR)
Abbreviations: WBC, white blood cell; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; SAA, serum amyloid A; IQR, interquartile range.