H syndrome presenting as juvenile diabetes: an underdiagnosed entity

H syndrome is a rare recessively inherited histiocytosis resulting from mutations in the SLC29A3 gene which encodes the human equilibrative nucleoside transporter 3 (hENT3).This multisystem disorder can have myriad of presentations ,with skin lesions ,sensory hearing loss and insulin dependent diabetes being the most characteristic.The most important step in the correct diagnosis involves awareness about the entity and careful physical examination. Genetic analysis is essential to confirm the diagnosis as it has many shared clinical features with other histiocytosis, with systemic manifestations which may confuse the physician. Management is symptomatic depending on the clinical presentation.Here we describe two genetically proven patients with H syndrome in whom diagnosis was missed for several years.Both patients presented in their second decade with clinical features suggestive of H syndrome. Increasing awareness is contributing to more reporting and helps in avoiding unnecessary evaluation.