People with Down's syndrome can be distinguished on the basis of cholinergic dysfunction.
The mydriatic response to eyedrops of the anticholinergic agent tropicamide at very low concentration (0.01%) has been studied in people with Down's syndrome. By comparison with healthy subjects people with Down's syndrome had responses approximately three times greater, suggesting a peripheral imbalance between cholinergic and adrenergic autonomic influences.
Sacks
B
B
Department of Psychiatry, Charing Cross and Westminster Medical School, London.
Smith
S
S
D000293:Adolescent; D000328:Adult; D002799:Cholinergic Fibers / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004314:Down Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009883:Ophthalmic Solutions; D011725:Pyridines; D011950:Receptors, Cholinergic / Q000187:drug effects* / Q000502:physiology; D012025:Reflex, Pupillary / Q000187:drug effects*; D014331:Tropicamide
D009883:Ophthalmic Solutions; D011725:Pyridines; D011950:Receptors, Cholinergic; D014331:Tropicamide