Joubert syndrome. cause of developmental delay and hypotonia in infancy and childhood

Joubert syndrome (js) is a rare disorder characterized by hypotonia,ataxia,abnormal eye movements,abnormal respiratory pattern,developmental delay and molar tooth sign on magnetic resonance imaging. most of the cases of joubert syndrome are sporadic. however joubert syndrome appears to be inherited in an autosomal recessive manner,via mutation in a number of genes including nphp,ahi1,and cep290. herein,we report nine children,belonging to independent families,with joubert syndrome (js); they shared the same clinical features and typical mri abnormality,known as molar tooth sign.