The Johanson-Blizzard syndrome (JBS) is rare and features complex dysplasias affecting multiple body systems.


Incidence: 1 in 250,000 (approximate)


Chromosome location: 15q15-q21

Gene affected: UBR1


Inheritance: autosomal recessive


Major features:

(1) congenital exocrine pancreatic insufficiency

(2) aplasia or hypoplasia of the nasal alae (wings)


Common findings:

(1) growth deficiency with short stature

(2) oligodontia and other dental abnormalities

(3) sensorineural hearing loss

(4) mental retardation

(5) midline scalp defects

(6) cutaneous fistula from the nasolacrimal duct


Variable findings (25-50%):

(1) renal and urinary tract abnormalities

(2) genital tract abnormalities including micropenis, cryptorchidism, etc

(3) imperforate anus or other anorectal anomalies

(4) hypothyroidism

(5) microcephaly


Other findings may include:

(1) hypopituitarism

(2) impaired glucagon secretion in response to insulin-induced hypoglycemia

(3) café-au-lait spots

(4) variable cardiac abnormalities

(5) variable ocular abnormalities


Complications of moderate to severe exocrine pancreatic insufficiency:

(1) diabetes mellitus

(2) malabsorption


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