What is Johanson-Blizzard syndrome (JBS)?
Johanson-Blizzard syndrome is a rare genetic syndrome. Symptoms of this syndrome usually affect multiple parts of the body. These symptoms are known to vary between individuals.
One of the defining symptoms of the syndrome is pancreatic insufficiency, an abnormality with the pancreas that triggers an inability from the intestine to absorb fats and other important nutrients that affect the development of the body.
This syndrome is also known as:
JBS Nasal Alar Hypoplasia, Hypothyroidism, Pancreatic Achylia, and Congenital Deafness
What gene change causes Johanson-Blizzard syndrome (JBS)?
Changes to the UBR1 gene cause the syndrome. It is inherited in an autosomal recessive pattern.
Autosomal recessive inheritance means an affected individual receives one copy of a mutated gene from each of their parents, giving them two copies of a mutated gene. Parents, who carry only one copy of the gene mutation will not generally show any symptoms but have a 25% chance of passing the copies of the gene mutations onto each of their children.
What are the main symptoms of Johanson-Blizzard syndrome (JBS)?
The main symptoms of the syndrome include the failure of the pancreas to absorb essential nutrients leads to a failure to thrive in many individuals, as well as a short stature, and a low weight.
Other symptoms include the uneven distribution of hair on the body, as well as alopecia which is hair loss.
A short nose and undeveloped nostril tissue are unique facial features of the syndrome
Possible clinical traits/features:
Autosomal recessive inheritance, Rectovaginal fistula, Single transverse palmar crease, Septate vagina, Sensorineural hearing impairment, Joint laxity, Short nose, Intrauterine growth retardation, Intellectual disability, Muscular hypotonia, Midline skin dimples over anterior/posterior fontanelles, Micropenis, Microdontia, Increased VLDL cholesterol concentration, Abnormal morphology of female internal genitalia, Anasarca, Reduced number of teeth, Ventricular septal defect, Calvarial skull defect, Situs inversus totalis, Death in childhood, Microcephaly, Urogenital fistula, Urethrovaginal fistula, Sparse scalp hair, Strabismus, Convex nasal ridge, Atrial septal defect, Lacrimation abnormality, Abnormal cardiac septum morphology, Cafe-au-lait spot, Absent lacrimal punctum, Aplasia cutis congenita of scalp, Anteriorly placed anus, Anal atresia, Alopecia, Agenesis of permanent teeth, Cholestasis, Abnormality of the nares, Abnormality of the nail, Abnormality of the upper urinary tract, Hydronephrosis.
How is it diagnosed?
To find out if someone has a diagnosis of Johanson-Blizzard (JBS), it is important to have a consultation and evaluation with a clinical genetic specialist. Specialists may also suggest specific genetic testing or other types of tests to help reach a diagnosis. FDNA’s AI technology can help speed up the diagnostic process by analyzing facial features and other health information.
