This is an extremely rare inherited condition that affects multiple parts of the body. The severity of this condition varies from one case to another presenting the abnormal facial features, dental problems and low birth weight. The signs and the symptoms are usually evident at the birth of the infant or early childhood. Although the exact prevalence of this syndrome is not known, it is estimated to affect around 1 in 250,000 births.
Causes
Johanson blizzard syndrome develops as the result of genetic mutation identified in the UBR1 gene. This gene is responsible for the production of a protein known as the UBR1 protein that is essential for various chemical processes of the body and is present at high levels in the exocrine cells of the pancreas. The genetic mutation results in the low levels of the functional UBR1 protein that causes the features characteristic of this syndrome. This is inherited in an autosomal recessive trait meaning the affected individual gets the same defective gene from each parent.
Symptoms
The symptoms and the severity of this condition vary from different cases. Most of the cases have the pancreatic insufficiency, abnormal shape of the nose that can appear to be ‘beak-shaped’ and tooth problems. They may have a small head, cleft lip, palate, poor muscle tone (hypotonia), low birth weight, failure to grow at the expected rate, problems with reaching developmental milestones and some exhibiting varying intellectual disability. They may also have growth deficiency from the malabsorption and diabetes from the problem with the insulin production.
Diagnosis
The diagnosis is based on the individual’s history, clinical evaluation and with the identification of the features characteristic of this syndrome. The hearing tests can evaluate the presence and the severity of the hearing loss and a CT scan can determine the fatty infiltration of the pancreas. These children should be screened for the potentially serious complications they can develop such as congenital heart problems, diabetes and hypothyroidism. The molecular genetic testing can identify the mutation in the gene that causes this disorder.
Treatment
The treatment for this syndrome is based on the specific symptoms that are evident in each of the cases. Individuals with the pancreatic insufficiency require pancreatic enzyme supplements to ensure the body properly absorbs the nutrients from the food consumed. Vitamin supplements may be required for those exhibiting vitamin deficiencies resulting from the malabsorption. In addition, these children will also require a special diet with high-protein in order to meet their growth requirement. Despite the improved nutrition, the children appear to be shorter and smaller than the average children. The thyroxine hormone replacement therapy may be needed for those exhibiting hypothyroidism. A surgical treatment may be optional for various abnormalities such as the craniofacial and genitourinary problems associated with this condition. In addition, the dental problems can be treated with the use of dentures or bonding agents and hearing aids may be beneficial for those suffering from hearing loss.
References
https://rarediseases.info.nih.gov/diseases/80/johanson-blizzard-syndrome
https://rarediseases.org/rare-diseases/johanson-blizzard-syndrome/