Joubert syndrome: a rare cause of hypotonia with developmental delay

Abstract

Joubert syndrome is a rare autosomal recessive disorder. It is characterized by congenital ataxia, hypotonia, developmental delay, and at least one of the following features: neonatal respiratory disturbances and abnormal eye movements; including nystagmus and oculomotor apraxia. Molar tooth appearance is an essential finding for the diagnosis of Joubert syndrome. Here we presented a case of an 18-month-old male who presented with developmental delay and marked hypotonia. The main purposes of the case report were to highlight the benefit of a multidisciplinary rehabilitation team approach and describe the clinical features associated with Joubert syndrome. Brain magnetic resonance imaging showed a thick, elongated, and abnormally oriented superior cerebellar peduncle showing a molar tooth appearance with elongated bat-wing-shaped 4th ventricle and hypoplasia of the vermis suggestive of JS. Hypotonia during infancy and developmental delay with or without learning disability, associated with abnormal breathing patterns and abnormal eye movements (nystagmus) along with the radiological presence of a molar tooth sign on the brain MRI is an essential component to confirm the diagnosis.