Wernicke-Korsakoff syndrome

Wernicke-Korsakoff syndrome is the classical manifestation of central nervous system (CNS) deficiency of thiamine caused by alcoholism.

S. S. Korsakoff was a 19th century Russian physician who observed amnesic patients with widespread brain damage from alcoholism.

Thiamine deficiency in alcoholic results from a combination of factors, including inadequate dietary intake, reduced gastrointestinal absorption, decreased hepatic storage and impaired use do thiamine.

Thiamine

Acutely, recent memory is impaired more severely than other metal tasks. In its acute stages, Wernicke–Korsakoff syndrome includes combinations of ataxia and ocular motility abnormalities, including conjugate gaze paresis, abducens nerve paresis, and nystagmus. However, only a minority of patients display all these abnormalities.

Not all alcoholics develop Wernicke-Korsakoff syndrome which suggest that genetic factors may be involved. The selective vulnerability to thiamine deficiency in different populations appears to be related to genetic variations of TK*(transketolase).
Wernicke-Korsakoff syndrome 

*TK is a key pentose phosphate shunt enzyme that plays an important role in the production of reducing equivalents and pentose sugars.