Table 1

Selection scheme for probands

Year of birth	Year of diagnosis	No of probands
1834–1860	Unrestricted	55
1865	Unrestricted	5
1875	Unrestricted	5
1899–1916	Unrestricted	46
1915–	1911–1984	725
1915–	1985	26
1954–1972	Unrestricted	85
Total		947