Two novel UBR1 gene mutations ın a patient with Johanson Blizzard Syndrome: A mild phenotype without mental retardation

Abstract

Johanson–Blizzard Syndrome (JBS) (MIM #243800) is a rare autosomal recessive genetic disorder characterized by exocrine pancreatic insufficiency, abnormal facial appearance and varying degrees of mental retardation. Mutations in UBR1 gene (MIM *605981) are considered to be responsible for the syndrome. Here, we report a 3year-old mentally normal JBS girl. The patient presented with exocrine pancreatic insufficiency as well as failure-to-thrive. On dysmorphological examination, she was noted to have an abnormal hair pattern with frontal upsweep and alae nasi hypoplasia. With these findings, JBS diagnosis was established clinically. Molecular analysis of the UBR1 gene revealed two inherited novel mutations; one coming from each parent. These novel mutations were c. 1280T>G and c. 2432+5G>C, and they were found to be disease causing via in-silico analysis.In conclusion, for patients with longstanding exocrine pancreatic insufficiency, it should be considered as being symptomatic of a far broader picture. To omit connection with rare genetic diseases, such as Johanson–Blizzard Syndrome, a detailed dysmorphological examination ought to be performed.