The following information may help to address your question:
What is Duane-radial ray syndrome?
Duane-radial ray syndrome (DRRS) is a disorder that affects the eyes and causes abnormalities of bones in the arms and hands. This condition is characterized by a particular problem with eye movement called
Duane anomaly (also known as Duane syndrome). Other features include bone abnormalities in the hands (malformed or absent thumbs, an extra thumb, or a thumb that looks like a finger) and partial or complete absence of bones in the forearm. Together, these hand and arm abnormalities are called radial ray malformations. DRRS is caused by
mutations in the
SALL4 gene and is
inherited in an
autosomal dominant manner.
[1][2] Treatment of DRRS may include surgery to correct Duane anomaly and radial ray malformations.
[2]
Last updated: 1/30/2017
What are the signs and symptoms of Duane-radial ray syndrome (DRRS)?
DRRS is characterized by a particular problem with eye movement called
Duane anomaly (also known as Duane syndrome). Duane anomaly results from the improper development of certain nerves that control eye movement. This condition limits outward eye movement (toward the ear), and in some cases may limit inward eye movement (toward the nose). As the eye moves inward, the eye opening becomes narrower and the eyeball may pull back (retract) into its socket. Duane syndrome may be unilateral (affecting only one eye) or bilateral (affecting both eyes).
[1][3]
Bone abnormalities in the hands include malformed or absent thumbs, an extra thumb, or a thumb that looks like a finger. Partial or complete absence of bones in the forearm is also common. Together, these hand and arm abnormalities are called radial ray malformations.
People with DRRS may have a variety of other signs and symptoms including unusually shaped ears, hearing loss, heart and kidney defects, a distinctive facial appearance, an inward- and downward-turning foot (a clubfoot), and fused spinal bones (vertebrae).[1]
Last updated: 1/30/2017
What causes Duane-radial ray syndrome (DRRS)?
DRRS is caused by mutations in the
SALL4 gene. The
SALL4 gene is part of a group of genes called the SALL family. These genes provide instructions for making
proteins that are involved in the formation of
tissues and
organs before birth. SALL proteins act as
transcription factors, which means they attach (bind) to specific regions of
DNA and help control the activity of particular genes. Mutations in the
SALL4 gene prevent one copy of the gene in each
cell from making any protein. It remains unclear how a reduction in the amount of SALL4 protein leads to Duane anomaly, radial ray malformations, and the other features of DRRS.
[1]
Last updated: 1/30/2017
How is Duane-radial ray syndrome (DRRS) inherited?
DRRS is inherited in an
autosomal dominant manner.
[1][2] This means that having a change (
mutation) in only one copy of the responsible
gene in each cell is enough to cause features of the condition.
In some cases, an affected person inherits the mutated gene from an affected parent. In other cases, the mutation occurs for the first time in a person with no
family history of the condition. This is called a
de novo mutation.
When a person with a mutation that causes an autosomal dominant condition has children, each child has a 50% (1 in 2) chance to inherit that mutation.
Last updated: 1/30/2017
Are there other conditions which closely resemble Duane-radial ray syndrome (DRRS)?
The varied signs and symptoms of DRRS often overlap with features of other disorders. In fact, some of these disorders are also caused by mutations in the
SALL4 gene. For example,
acro-renal-ocular syndrome is characterized by Duane anomaly and other eye abnormalities, radial ray malformations, and kidney defects. Both conditions can be caused by mutations in the same gene. Based on these similarities, researchers are investigating whether DRRS and acro-renal-ocular syndrome are separate disorders or part of a single syndrome with many possible signs and symptoms. The features of DRRS also overlap with those of a condition called
Holt-Oram syndrome; however, these two disorders are sometimes caused by mutations in different genes.
[1][2]
Last updated: 1/30/2017
How might Duane-radial ray syndrome (DRRS) be treated?
The treatment of DRRS may vary and often requires a team of specialists. Severe
strabismus associated with Duane syndrome and malformations of the hands and forearms may require eye surgery. Individuals with heart defects may also require corrective surgery. Hearing aids may be needed for those with hearing deficits. Growth
hormone therapy may additionally be considered for individuals with
short stature. Since kidney issues may develop, renal monitoring should also be considered.
[2]
Last updated: 1/30/2017
We hope this information is helpful. We strongly recommend you discuss this information with your doctor. If you still have questions, please
contact us.
Warm regards,
GARD Information Specialist
Please see our Disclaimer.
