Atelosteogenesis type 2

Description

Atelosteogenesis type 2 is a severe disorder of cartilage and bone development. Infants born with this condition have very short arms and legs, a narrow chest, and a prominent, rounded abdomen. This disorder is also characterized by an opening in the roof of the mouth (a cleft palate), distinctive facial features, an inward- and upward-turning foot (clubfoot), and unusually positioned thumbs (hitchhiker thumbs).

The signs and symptoms of atelosteogenesis type 2 are similar to those of another skeletal disorder called diastrophic dysplasia; however, atelosteogenesis type 2 is typically more severe. As a result of serious health problems, infants with this disorder are usually stillborn or die soon after birth from respiratory failure. Some infants, however, have lived for a short time with intensive medical support.

Frequency

Atelosteogenesis type 2 is an extremely rare genetic disorder; its incidence is unknown.

Causes

Atelosteogenesis type 2 is one of several skeletal disorders caused by mutations in the SLC26A2 gene. This gene provides instructions for making a protein that is essential for the normal development of cartilage and for its conversion to bone. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. Mutations in the SLC26A2 gene disrupt the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems characteristic of atelosteogenesis type 2.

Inheritance

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

Autosomal recessive inheritance. Credit: U.S. National Library of Medicine.

Other Names for This Condition

• AO2
• Atelosteogenesis de la Chapelle type
• Atelosteogenesis, type 2
• De la Chapelle dysplasia
• McAlister dysplasia
• Neonatal osseous dysplasia 1

Where this page came from

This page was imported from MedlinePlus Genetics, National Library of Medicine. Courtesy of MedlinePlus from the National Library of Medicine; its genetics summaries and the illustrations credited to the library are in the public domain. Pictures credited to others are not copied.

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