Trigger is Down syndrome, either at the front of the prompt or SUBJECT with Down syndrome (or both for longer prompts)
Strength .8-.9 for realism, going higher works but can be a bit exaggerated.
I made this as the person who made the excellent Chromosome lora for SDXL and 1.5 has not updated for Flux. Consider this a holdover for now, but I may expand on it and train a little better next time for better clarity over 1.0 and deal with some of the rosy cheeks that pop up.