Johanson-Blizzard syndrome (JBS), named for two of the first scientists to study it, is a type of ectodermal dysplasia, a group of diseases that affect the outer layer of a developing embryo. This layer, called the embryonic ectoderm, develops into the hair, skin, nails, and teeth. Symptoms of JBS affect the teeth, hair, face, brain, thyroid gland, and ears.
JBS is caused by a mutation, or defect, in the ubiquitin protein ligase (UBR1) gene. This gene seems to have a role in the normal functioning of the pancreas. People with JBS usually have decreased functioning of the pancreas, which often causes short stature and poor nutrient absorption, and is generally the cause of death in these individuals.
JBS is extremely rare, with about only 30 known cases worldwide. More cases have been reported in females than in males, but females tend to have milder symptoms. Incidence is higher among children of parents who are consanguineous, meaning they are related and share a blood line.
There is no cure for JBS. Treatment aims to reduce symptoms and prevent complications. Even when treated aggressively, people with JBS often die in infancy or early childhood. This is largely because of problems associated with malnutrition.
Autosomal recessive, ectodermal dysplasia, ectodermal dysplasia-exocrine pancreatic insufficiency, ectodermal dysplastic disorder, hypothyroidism, JBS, Johanson-Blizzard's syndrome, malabsorption-ectodermal dysplasia-nasal alar hypoplasia.