Do Both Parents Have To Be Carrier For Tay-Sachs? Do both parents have to be carrier for Tay-Sachs? Both parents must be TS carriers to be at risk for a baby with TS. If one parent has a negative (normal) test result, the chance that a baby will have Tay-Sachs disease is very small. Testing
Does Down Syndrome Affect Phenotype? Does Down syndrome affect phenotype? Down syndrome is characterized by extensive phenotypic variability; while cognitive impairment, muscle hypotonia at birth, and dysmorphic features occur to some extent in all affected individuals, most associated traits occur in only a fraction of affected individuals. What phenotype is associated with Down syndrome? Down