Footnote
a Itrisomy 21 sisifo umntwana azalwa naso esidodobalisa ingqondo. Ngokuqhelekileyo, umntu uba neechromosome ezingambini, kodwa kubantwana abazelwe benetrisomy kubakho eyesithathu. Itrisomy 21 ibakho kwichromosome yama-21.
a Itrisomy 21 sisifo umntwana azalwa naso esidodobalisa ingqondo. Ngokuqhelekileyo, umntu uba neechromosome ezingambini, kodwa kubantwana abazelwe benetrisomy kubakho eyesithathu. Itrisomy 21 ibakho kwichromosome yama-21.