Table 2.
Comparison of Characteristics of DS-Affected Individuals and Model Systems
| DS-Affected Individuals | Rodent Models | Human Stem Cell Models | |
|---|---|---|---|
| Physical symptoms | altered craniofacial structurea | altered craniofacial structurea | ND |
| short stature | ND | ND | |
| Behavioral symptoms | severe cognitive deficits (learning and memory, executive function) | some cognitive deficits and variable resultsb | ND |
| Brain and neuronal deficits | decreased brain size | ND | reduced neuronal differentiation, no difference, variable results |
| reduced excitatory and inhibitory neurons | increased inhibitory neuronsc | reduced inhibitory neurons | |
| dendritic spine defects | dendritic spine defects | ND | |
| Alzheimer disease pathologyd | increased amyloid beta proteind | increased amyloid beta proteind | |
| Neuronal functional deficits | oxidative stressd | oxidative stressd | oxidative stressd |
| decreased neurogenesis and proliferation | variable increased and decreased neurogenesisb | decreased neurogenesis and proliferation | |
| ND | increased inhibition | ND | |
| decreased myelinationa | decreased myelinationa | ND | |
| Genetic basis | trisomy 21a | each animal model has different combinations of orthologous HSA21 genes; some have triplicated non-HSA21 genesc | trisomy 21a |
| Molecular deficits and targets | upregulation of some HSA21 genes; downstream consequences on whole genomea | different sets of genes; potentially different downstream consequencesc | upregulation of some HSA21 genes; downstream consequences on whole genomea |
The following abbreviation is used: ND, no data.
a
Consistent between DS-affected individuals and only one of the experimental models.
b
Large variability in behavioral deficits was observed. See Herault et al.142 for a review.
c
Not consistent between experimental models and DS-affected individuals.
d
Consistent among DS-affected individuals and both experimental models.