What is the definition of Acromesomelic Dysplasia?

Acromesomelic dysplasia describes a group of extremely rare, inherited, progressive skeletal conditions that result in a particular form of short stature, called short-limb dwarfism. The short stature is the result of unusually short forearms and forelegs (mesomelia) and abnormal shortening of the bones in the hands and feet (acromelia). At birth, the hands and feet may appear abnormally short and broad. Over time, the apparent disproportion becomes even more obvious, especially during the first years of life. Additional features may include: limited extension of the elbows and arms; progressive abnormal curvature of the spine; an enlarged head; and a slightly flattened midface. Acromesomelic dysplasia is inherited as an autosomal recessive trait.

There are different types of acromesomelic dysplasia, which are distinguished by their genetic cause. To read more about the different types, click on the links below.
Acromesomelic dysplasia, Maroteaux type
Acromesomelic dysplasia, Hunter-Thompson type
Acromesomelic dysplasia, Grebe type

What are the alternative names for Acromesomelic Dysplasia?

  • Acromesomelic dwarfism

What are the symptoms for Acromesomelic Dysplasia?

Affected infants often have a normal birth weight. In most cases, in addition to having unusually short, broad hands and feet, affected infants often have characteristic facial abnormalities that are apparent at birth. Such features may include a relatively enlarged head, unusually prominent forehead, pronounced back portion of the head (occipital prominence), a slightly flattened midface, and/or an abnormally small, pug nose.

During the first years of life, as the forearms, lower legs, hands, and feet do not grow proportionally with the rest of the body, short stature (short-limb dwarfism) begins to become apparent. Over time, affected individuals may be unable to fully extend the arms, rotate the arms inward toward the body with the palms facing down, or rotate the arms outward with the palms facing upward. In some cases, affected individuals may also experience progressive degeneration, stiffness, tenderness, and pain of the elbows (osteoarthritis). 

Abnormalities of cartilage and bone development may also cause the bones within the fingers, toes, hands, and feet to become increasingly shorter and broader during the first years of life. During the second year of life, the growing ends of these bones may begin to appear abnormally shaped like a cone or a square and may fuse prematurely. This causes the fingers and toes to appear short and stubby. The hands and feet may seem unusually short, broad, and square; and the feet may appear abnormally flat. In early childhood, extra, loose skin may also develop over the fingers.

During early childhood, affected individuals may also begin to experience progressive, abnormal curvature of the spine. In rare cases, affected individuals can experience delayed puberty and corneal clouding.

What is the outlook (prognosis) for Acromesomelic Dysplasia?

Acromesomelic dysplasia is a progressive condition, meaning that signs and symptoms usually become worse over time. However, life expectnacy appears to be normal. Abnormal cartilage and bone development usually affects many bones in the body, particularly those of the hands and feet. Over time, the bones may becomre more disproportionate. The joints may be affected as well. Many affected individuals experience abnormal curvature of the spine.