Human chromosomes (IMAGE) Charité - Universitätsmedizin Berlin Caption DNA of a healthy human cell with 26 chromosomes in all. Extra chromosomes normally cause a harmful genetic imbalance. © CDC | Suzanne Trusler, MPH, DrPH Credit © CDC | Suzanne Trusler, MPH, DrPH Usage Restrictions No restrictions. License Public Domain Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.