Table 1

Comparison of the type of study, rate of familial amyotrophic lateral sclerosis, source of case ascertainment and case inclusion criteria for each study

Country	Years	FALS	Total ALS	% FALS	Ascertainment	Diagnosis	Comments
Group 1: prospective population based registry
Puglia, Southern Italy	1998–1999	2	130	1.50	A, B, C, D, G, K	Bii, H, J, L, N
Piemonte, Northern Italy	1995–2004	53	1260	4.20	A, D, H	Bii, N
Scotland	1989–1998	59	1226	4.80	A, B, D, G, H, J	B, C
South-East England	2002–2006	31	472	6.60	A, B, C, G, J	Bii, H
Washington, USA	1990–1994	9	174	5.20	B, G	G, H, K, L	Personal communication with author
San Francisco, USA	1970–1986	52	708	7.30	A, B, C, G, H, L	A, D, H, J, N	Only paper to give criteria for familial ALS
Uruguay	2002–2003	6	143	4.20	A, B, H, J	Bi, I, K, M	States based on detailed family history
Ireland	1995–2009	53	1170	4.50	A, B, C, G, H, L	Bii, N	Up to date registry data (November 2009)

Group 2: retrospective population based study
New Zealand	1985–2006	10	244	4.10	B, C, D, L	Bi, G, I, K
Rochester, USA	1925–1998	3	77	3.90	E	P
Modena, Italy	1990–1999	4	143	2.80	C, H, J, L	Bi
Jefferson County, USA	1998–2002	2	36	5.50	B, C, D, G, H, I	Bi, I, M	Prevalence study looking for cluster
Ontario, Canada	1978–1982	6	139	4.30	C, G, H	D, H, K, L
Middle Finland	1976–1981	5	43	11.60	D, H	D, O
Northern Sweden	1969–1980	6	128	4.70	E, H, M	A, D, O	States that 4.7% should be taken as a minimum value
Cantabria, Spain	1974–1985	3	65	4.60	E	D, H, I	Poor case ascertainment
Sardinia, Italy	1957–1980	4	182	2.20	C	D	Poor case ascertainment. FALS limited to first degree relative
South-West Greece	1990–2003	2	133	1.50	E	Bi, F, I, N
Belgrade, Yugoslavia	1985–1991	1	58	1.70	C	D, N	Poor ascertainment
Hong Kong	1989–1992	1	84	1.20	B, C, L, H	Bi, F, H, J, L, N
Northern Denmark	1974–1986	5	186	2.70	C	D, O
Hordaland, Norway	1970–1990	7	148	4.70	E, F, H	D, O

Group 3: prospective case series
Texas, USA	1982–1994	114	1200	9.50	E	E, N	States that data interpretation must be made in light of non-random enrolment
New York, USA	1973–1977	33	668	4.90	M	D
Colorado, USA	1989–1991	4	167	2.40	C	D, E, N

Group 4: retrospective case series
Brazil	1977–2004	7	251	2.80	E	Bii, G, I, K, N
London, UK	1965–1984	27	580	4.70	C	D	Case notes from 3 London hospitals. 37 FALS cases not verified—rate could be 10%
Rochester, USA	Pre 1955	5	58	9	E	D
Lazio, Italy	1987–2007	23	531	4.30	E	Bii, N
Novia Scotia, Canada	Pre 1974	3	52	5.80	E	D, F, H, J, L
Leuven, Belgium	1991–1995	12	140	8.60	E	Bi, H, J, L	Especially high rate SOD1 mutation
Israel	1959–1975	3	318	1	C, I, M	C, D, E, N
Netherlands	1970–1988	20	307	6.50	E	D, G, I, K

Key	Ascertainment	Key	Diagnostic criteria
A	Prospective register	A	Post mortem
B	All neurologists	B	El Escorial criteria
C	Multicentre hospital records	Bi	EEC definite, probable
D	Multicentre discharge records	Bii	EEC definite, probable, suspect
E	Single centre hospital records	C	Simplified EFN criteria
F	Single centre discharge records	D	Diagnosed by neurologist pre-criteria
G	ALS association records	E	ALS rated using institutions own scoring system
H	Death certificates	F	SMA included
I	Compulsory reporting	G	SMA excluded
J	EMG archives	H	PMA included
K	Control drug registry	I	PMA excluded
L	Private neurologists	J	PLS included
M	Questionnaire	K	PLS excluded
		L	PSP included
		M	PSP excluded
		N	EMG >80% patients
		O	EMG <80% patients

ALS, amyotrophic lateral sclerosis; EEC, El Escorial criteria; FALS, familial amyotrophic lateral sclerosis; PMA, progressive muscular atrophy; PSP, progressive supranuclear palsy; SMA, spinal muscular atrophy; WFN, World Federation of Neurology.