This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Parkinsonism and other movement disorders, Subject name: Medicine
All are associated with decreased sense of smell except? 
Select and explain. 
A. Parkinsonism, B. Kallmann Syndrome, C. Gullain barre syndrome, D. HIV infection
C: Gullain barre syndrome
Answer: C: Gullain barre syndrome 
Explanation: Gullain barre syndrome does not present with anosmia Non-motor symptoms of Parkinsonism are constipation, anosmia, and REM behavior sleep disorder. Kallmann syndrome presents with anosmia due to olfactory bulb agenesis/ hypoplasia. HIV infection can also affect olfactory bulbs leading to anosmia