Wolfram syndrome (WS), also known as DIDMOAD (due to its association with diabetes insipidus, diabetes mellitus, optic atrophy and deafness), is an infrequent cause of diabetes mellitus. This syndrome is included among the genetic disorders associated with diabetes in the American Diabetes Association's classification. WS is an autosomal recessive neurodegenerative disease characterized by various clinical manifestations such as diabetes mellitus, optic atrophy, diabetes insipidus, deafness, neurological symptoms, renal tract abnormalities, psychiatric disorders and gonadal disorders. The most frequent of these disorders is early onset diabetes mellitus, with a low prevalence of ketoacidosis, and optic atrophy, which is considered a key diagnostic criterion in this syndrome. Diabetes insipidus usually develops later. This syndrome manifests in childhood, hampering diagnosis and treatment. Morbidity and mortality are high and quality of life is impaired due to neurological and urological complications. This article describes the clinical characteristics and outcome in three patients with WS. All three patients had antecedents of consanguinity. Genetic study was performed in all patients. One was homozygotic for the WFS1 gene that encodes the WFS1 G736A mutation in exon 8 and the remaining two patients, who were siblings, were homozygotic for the 425ins16 mutation in exon 4.