Johanson-Blizzard syndrome (JBS) is an autosomal recessively inherited disorder that is characterized by pancreatic insufficiency, a distinct appearance with hypo- or aplasia of the alae nasi and dental anomalies. We report on 3 patients with JBS who demonstrate the clinical variability of additional symptoms. In contrast to the common mental retardation in JBS we stress the outstanding intellectual abilities of one patient. It is important to realize the treatable dysfunctions in JBS. Specific therapy of e.g. pancreatic insufficiency and hypothyroidism can lead to a marked improvement of the clinical course. For the first time we discuss a possible sex influence. There is evidence that females have a better prognosis. The literature is reviewed, and aspects of differential diagnosis of JBS are considered.