Common indications for referral (lID 8. Before undertaking genetic testing and after receiving results, particularly when testing for susceptibility to late-onset disorders, such as cancer or neurological disease 9. As follow-up for a positive newborn test as with PKU, or a heterozygote screening test, such as Tay-sachs.Common indications for referral (III) 8. Before undertaking genetic testing and after receiving results,particularly when testing for susceptibility to late-onset disorders, such as cancer or neurological disease. 9. As follow-up for a positive newborn test, as with PKU, or a heterozygote screening test, such as Tay-Sachs