Answer
A. Eaton-Lambert syndrome results from auto-antibody blocking 
the release of acetylcholine ie. pathology in the pre-synaptic
neuromuscular junction. Ocular involvement causing motility 
problems has been reported but rare.

Answer
D. Demyelination of the axons is the main pathology in multiple sclerosis.

Answer
F. Ragged red fibres are seen in this condition due to abnormal
mitochondrial DNA. Apart from abnormal eye movement, there
is ptosis and pigmentary retinopathy.

Answer
B. Botulinum toxin combines with vesicles containing acetylcholine 
and prevent their release into the neuromuscular junction. The pathology
is in the presynaptic neuromuscular junction.

Answer
D. Louis-Bar syndrome also known as ataxia-telangiectasia has
no central nervous system abnormalities that can be detected on 
MRI scan.

Answer
B. Several phakomatosis are associated with mental retardation 
and epilepsy but only in Sturge-Weber syndrome is there calcification
of the cerebral blood vessels.

Answer
A.Wyburn-Mason syndrome contains arteriovenous malformations with dilated tortuous vessels in the retina and the central nervous system.

Answer
C. von Hippel-Lindau is the only one which has all the above features. 
The ataxia and polycythaemia are the results of cerebellar 
haemangioblastoma that secretes erythropoietin. 

Answer
F. Subungual fibroma is characteristic of tuberous sclerosis which
also has the other the other features.