Text Box: TUBEROUS SCLEROSIS PRESENTED WITH CLASSICAL LANDAU KLEFFNER SYNDROME Wickramasinghe.H.T1, Wint.Z2 , Rohayati H. M. T1 1RIPAS Hospital, Bandar Seri Begawan, Brunei 2Community paediatrician, Bandar Seri Begawan, Brunei Objective: Tuberous sclerosis and Landau Kleffner syndrome are two distinct diseases of central nervous system. Tuberous sclerosis is a autosomal dominant multisystem disorder that is characterized by varying degrees of mental retardation with distinctive and diagnostic skin abnormalities. Mutations of at least two different genes are known to cause Tuberous sclerosis. Landau Kleffner syndrome (LKS), on the other hand, is a rare, acquired childhood neurological disorder of unknown aetiology, characterized by sudden or gradual loss of understanding language followed by loss of speech with abnormal electro-encephalogram (EEG). In addition most of these children have variable spectrum of abnormal behavioural patterns resembling autism, attention deficit hyperactive syndrome. Neither structural abnormalities nor genetic mutations had been implicated in the aetiology. Method and results: In the international classification, Landau Kleffner syndrome is placed under “Epilepsy and Syndromes” undetermined as to whether focal or generalized. We report a case of Tuberous sclerosis presented with classical Landau Kleffner syndrome. This shows like many epileptic syndromes, Landau Kleffner syndrome is also hetrogenous. All cases of Landau Kleffner syndromes therefore need to be thoroughly investigated to exclude possible structural abnormalities. 2483