Radial-ray Duane syndrome ... (Duane-radial ray syndrome) - Gen Sall4.
Duane syndrome Radial-ray is a disorder that affects the eyes and cause bone abnormalities in the arms and hands. This alteration is characterized by a particular problem with eye movement called anomaly Duane (also known as Duane syndrome). This anomaly is caused by the inadequate development of certain nerves that control eye movement, limiting the outward movement of the eye (to the ear), and in some cases can limit the inward movement of the eye ( near your nose). Furthermore, as the eye moves inward, the eye opening becomes narrower and the eyeball can be retracted at its base. Bone abnormalities include malformations radial axis, as malformed or absent thumbs, an additional thumb, a long thumb seems a finger, or the partial or complete absence of the forearm bones. Other signs and symptoms include unusual ears, hearing loss, heart defects and kidney, a characteristic facial appearance, clubfoot and fused vertebrae.
Signs and symptoms of Duane-radial ray syndrome often overlap with features of other diseases. For example, the syndrome acro-renal-ocular characterized by Duane anomaly and other ocular abnormalities, malformations radial axis, and renal defects. Both changes are caused by mutations in the same gene. Based on these similarities, is believed to Duane syndrome Radial-ray and acro-renal syndrome-ocular are part of a set of syndromes with many signs and symptoms possible. The features of Duane-radial ray syndrome are also similar to those of a condition called Holt-Oram syndrome of. However, these alterations are caused by mutations in different genes.
This disease is due to mutations in the gene Sall4, located on the long arm of chromosome 20 (20q13.2). This gene is part of a group of genes called the SALL family. These genes encode proteins transcription factors that are involved in the formation of tissues and organs during embryonic development. The exact function of the protein Sall4 remains unclear. Based on the functions of similar proteins in other organisms (such as zebrafish and mice), this protein appears to play a critical role in developing limbs. This protein may also be important for the development of the nerves that control eye movement and for the formation of septa dividing the heart into separate chambers.
They have identified more than 25 mutations in the gene Sall4 in people with Duane-radial ray syndrome. Most mutations create a premature stop signal in encoding the protein. As a result, the cells do not encode any functional protein from a copy of this gene. It is being studied as a reduction in the amount of protein Sall4 interrupts the development of limbs, eye and heart.
This disease is inherited in an autosomal dominant, which means that a copy of the altered gene in each cell is sufficient to cause the alteration. In many cases, an affected person inherits a mutation from an affected parent. Other cases are caused by new mutations in the gene and occur in people with no history of disease in your family.
Tests in IVAMI: in IVAMI perform detection of mutations associated with Radial-ray Duane syndrome by complete PCR amplification of the exons of the gene Sall4, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leuco cytes, or impregnated sample card with dried blood (IVAMI may mail the card to deposit the blood sample).