Table 3

Subgroup analysis of frequencies according to population and study design in patients with ALS with major ALS-related mutation

			FALS						SALS
Gene	Category	Subgroup	Studies	Cases	Mutation rate (95% CI)	I² (%)	Q	p (Q)	Studies	Cases	Mutation rate (95% CI)	I² (%)	Q	p (Q)
SOD1	Population	European	32	2315	0.148 (0.115 to 0.185)	80	2120	<0.0001	26	5765	0.012 (0.007 to 0.019)	77	0.10	0.75
	Population	Asian	16	319	0.300 (0.251 to 0.351)	23	2120	<0.0001	10	2046	0.015 (0.010 to 0.020)	49	0.10	0.75
	Study design	HB	43	2412	0.202 (0.171 to 0.236)	69	4.17	0.04	31	6177	0.013 (0.008 to 0.020)	70	0.63	0.43
	Study design	PB	5	222	0.069 (0.006 to 0.192)	86	4.17	0.04	5	1634	0.008 (0.001 to 0.022)	81	0.63	0.43
TARDBP	Population	European	17	1064	0.042 (0.016 to 0.078)	83	1.17	0.28	28	7847	0.008 (0.002 to 0.015)	90	5.36	0.02
	Population	Asian	9	203	0.015 (0.000 to 0.060)	63	1.17	0.28	12	2834	0.002 (0.000 to 0.003)	24	5.36	0.02
	Study design	HB	23	1076	0.033 (0.012 to 0.065)	80	0.04	0.85	37	8666	0.005 (0.001 to 0.010)	89	0.10	0.75
	Study design	PB	3	191	0.027 (0.000 to 0.105)	80	0.04	0.85	3	2015	0.006 (0.002 to 0.011)	37	0.10	0.75
FUS	Population	European	22	1936	0.028 (0.021 to 0.035)	47	5.14	0.02	21	9556	0.003 (0.001 to 0.005)	54	2.46	0.12
	Population	Asian	7	171	0.064 (0.032 to 0.105)	0	5.14	0.02	5	1321	0.009 (0.002 to 0.019)	63	2.46	0.12
	Study design	HB	26	1916	0.031 (0.024 to 0.039)	41	0.37	0.55	23	8862	0.004 (0.002 to 0.007)	59	1.10	0.29
	Study design	PB	3	191	0.018 (0.000 to 0.071)	71	0.37	0.55	3	2015	0.002 (0.000 to 0.006)	57	1.10	0.29
C9orf72	Population	European	23	2366	0.337 (0.293 to 0.382)	77	67.23	<0.0001	25	14 373	0.051 (0.043 to 0.060)	78	111.84	<0.0001
	Population	Asian	10	264	0.023 (0.003 to 0.063)	58	67.23	<0.0001	11	3802	0.003 (0.001 to 0.006)	51	111.84	<0.0001
	Study design	HB	29	2390	0.200 (0.144 to 0.263)	91	12.39	0.0004	32	15 544	0.029 (0.019 to 0.041)	94	2.18	0.14
	Study design	PB	4	240	0.396 (0.303 to 0.489)	55	12.39	0.0004	4	2631	0.046 (0.027 to 0.070)	83	2.18	0.14

ALS, amyotrophic lateral sclerosis; FALS, familial amyotrophic lateral sclerosis; HB, hospital-based study; I², percentage of heterogeneity caused by study differences; PB, population-based study; p (Q), p value for heterogeneity between subgroups; Q, heterogeneity between subgroups; SALS, sporadic amyotrophic lateral sclerosis.