Johanson-Blizzard syndrome ... (Johanson-Blizzard Syndrome) - Gen UBR1.
Syndrome Johanson-Blizzard (JBS) is a disease characterized by growth retardation, mental retardation and dysmorphic features variables, including aplasia or hypoplasia of the nostrils, abnormal patterns hair or scalp defects, and oligodontia. Other features include hypothyroidism, sensorineural hearing loss, imperforate anus, and exocrine pancreatic insufficiency.
This process is due to mutations in the UBR1 gene, located on the long arm of chromosome 15 (15q13). This gene encodes an E3 ubiquitin ligase pathway N-terminal a ubiquitin - dependent proteolytic pathway. This protein binds to specific proteins bearing N-terminal residues that are destabilizing, with a view to its ubiquitination and degradation. In addition, they may be involved in pancreatic homeostasis. It is considered that the UBR1 gene, plays a critical role in the development and maintenance of the acinar cells.
Mutations in the gene UBR1 alter, disrupt or impede the synthesis of ubiquitin ligase, which leads to encoding a nonfunctional or partly nonfunctional protein. Deficiency UBR1 functional protein causes impaired pancreatic acinar cells and other organs. These changes lead to the destruction of acinar tissue, which may begin in the womb, lead to the development of exocrine pancreatic insufficiency and fatty infiltration of the pancreas.
This disease is inherited in an autosomal recessive pattern, that is, both copies of the gene in every cell must have mutations for alteration is expressed. The parents of an individual with an autosomal recessive disease have a copy of the mutated gene, but usually show no signs and symptoms of the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with Johanson-Blizzard of (JBS) syndrome by complete PCR amplification of exons UBR1 gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).