This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitreous and retina, Subject name: Ophthalmology
Retinitis Pigmentosa is associated with all except - 
Select and explain. 
A. Usher Syndrome, B. Marfan's Syndrome, C. Kearns- Sayre Syndrome, D. Bussen - Kornzweig Syndrome
B: Marfan's Syndrome
Answer: B: Marfan's Syndrome 
Explanation: Systemic associations. These are in the form of following syndromes: 1. Laurence-Moon-Biedl syndrome. It is characterised by retinitis pigmentosa, obesity, hypogenitalism, polydactyly and mental deficiency. 2. Cockayne's syndrome. It comprises retinitis pigmentosa, progressive infantile deafness, dwarfism, mental retardation, nystagmus and ataxia. 3. Refsum's syndrome. It is characterised by retinitis pigmentosa, peripheral neuropathy and cerebellar ataxia. 4. Usher's syndrome. It includes retinitis pigmentosa and labyrinthine deafness. 5. Hallgren's syndrome. It comprises retinitis pigmentosa, vestibulo-cerebellar ataxia, congenital deafness and mental deficiency. Ref : comprehensive ophthalmology AK khurana 4/e page no 269 .