Table 1: Definite and probable morbid risk of schizophrenia
Relationship
% Shared genes
Risk (%)
a.
General population
N.A.
1
b.
Spouses of patients
N.A.
2
c.
Third-degree relatives
12.5
-
-
first cousins
-
2
d.
Second-degree relatives
25
-
-
uncles/aunts
-
2
-
nieces/nephews
-
4
-
grandchildren
-
5
-
half-siblings
-
6
e.
First-degree relatives 50 -
-
parents - 6
-
siblings - 9
-
children - 13
-
siblings with 1 schizophrenia parent
-
17
-
dizygotic twin
-
17
f.
Monozygoyic twin
100
48
g.
Children with 2 schizophrenia
100
46
from Tsuang (2000)
2