HNPP

Hereditary neuropathy with liability to pressure palsies (HNPP) is  a genetic disease consistent with autosomal inheritance. PMP 22 gene mutation is the fundamental mechanism; consistent with frameshift mutation.  PMP 22 gene’s product is a peripheral myelin protein responsible of peripheral nerves’ endurance and resistance.  Charchot Marie Tooth Disease Type 1A (CMT1A ) and CMT1E also  share same gene deletion mechanism  located in  17p 11.2  choromosome.  

Wernicke Encephalopathy

Thiamine is a water soluable - thermolabile vitamine which is vital to sustain osmotic gradients of cell membranes and also involved in glucose metabolism and neurotransmitter synthesis. Wernicke encephalopathy (WE) is an acute neurologic disorder caused by lack of dietary intake or excessive need of thiamine. Bariatric surgery, pregnancy, haematologic malignencies, dextrose infusion, parenteral nutrition are some notable reasons among alcoholism.  In WE, the blood-brain barrier becomes defective in the periventricular regions, in which there is a high rate of thiamine-related glucose and oxidative metabolism. Mamillary bodies, the medial portions of the thalamus and hypotalamus, the periaquaductal region of the mid brain and certain structres in the floor of the forth ventricle; tectal plate and dorsal medulla are main regions affected by disese manifestation. The classical clinical triad is consisting of ocular signs, altered consciousness and ataxia.

Wernicke encephalopathy is a  serious neuropshyciatrical condition needs urgent recognation and treatment and otherwise can be fatal or cause disability.   Many case reviews suggest non alcoholic  WE imaginings differ from alcoholic WE. In alcoholic population, periaquaductal gray matter region  and mamillar body are more prone  to be effected and  forms the classical WE imagining presentation.  In non alcoholic  population, atypical involvemets such as cerebellum, periventricular white matter, cerebral cortex  are  more widespreadly  distinguished.

Genetic  predisposition, increased permeability  and vulnerability of cells due to alcohol, bots of thiamin deficiency and duration of insufficiency are speculated explanations for different imagining properities. Early sytotoxical oedema can be shown by diffusion weighted images and  FLAIR images. Haemosyderin depositions in mamillary bodies can be shown in T1 weighted images. Necrosis and petechial haemorrhages can be shown in T2 weighted images.