Although No Specific Gene Alteration Has Yet Been Demonstrated as a Cause

Although no specific gene alteration has yet been demonstrated as a cause for schizophrenia (SZ) , it is known to have a strong genetic component. A recent study has found a strong association between SZ and a locus at chromosome 10q22- 23 in Ashkenazi Jewish and Taiwanese Han populations. Which of the following is probable?

A) The neuregulin- 3 gene at this locus is mutated in all or most SZ cases.
B) Other populations will have the same association with 10q22- 23.
C) SZ exhibits significant genetic heterogeneity in different populations.
D) People with SZ being characterized differently in various medical communities results in this association between the Jewish and Han populations.
E) The region on 10q must include several genes associated with SZ.