Description

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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