Holt-Oram syndrome , HOS (Abkürzung)

About 75 percent of individuals with Holt-Oram syndrome have heart problems.

Holt-Oram syndrome is considered an autosomal dominant disorder.

Holt-Oram syndrome is a disorder that affects bones in the arms and hands (the upper limbs) and may also cause heart problems.

Holt-Oram syndrome is considered to be a phenocopy of thalidomide, since both the genetic disorder and the teratogenic effects have similar presentations in individuals.

While visiting, he noticed Nicole Worley-Urteaga, a 2-year-old patient with Holt-Oram syndrome.

Mutations in the TBX5 gene cause Holt-Oram syndrome.

Mutations in this gene probably disrupt the development of the heart and upper limbs, leading to the characteristic features of Holt-Oram syndrome.

Sometimes people with Holt-Oram syndrome have cardiac conduction disease, which is caused by abnormalities in the electrical system that coordinates contractions of the heart chambers.

Holt-Oram syndrome is an autosomal dominant genetic condition that is associated with an abnormality in the TBX5 gene.

Cardiac conduction disease can occur along with other heart defects (such as septal defects) or as the only heart problem in people with Holt-Oram syndrome.

The features of Duane-radial ray syndrome also overlap with those of a condition called Holt-Oram syndrome; however, these two disorders are caused by mutations in different genes.

Other cases of Holt-Oram syndrome are sporadic, and result from new mutations in the TBX5 gene that occur in people with no history of the disorder in their family.

Holt-Oram syndrome, Fanconi anemia: aplastic anemia at the age of 6, Townes-Brocks syndrome, Greig cephalopolysyndactyly: also occurs with ulnar polydactyly.

Examples of syndromes with an hypoplastic thumb are Holt-Oram syndrome, VACTERL association and thrombocytopenia absent radius (TAR) syndrome.

In humans, two T-box genes are involved in inherited disorders: mutations in TBX5 cause Holt-Oram syndrome, whereas mutations in TBX3 cause ulnar-mammary syndrome.

In case of an inherited condition, several syndromes are known for an association with radial dysplasia, such as the cardiovascular Holt-Oram syndrome, the gastrointestinal VATER syndrome and the hematologic Fanconi anemia and TAR syndrome.

In humans and some other animals, defects in the TBX5 gene expression can lead to finger-like thumbs and ventricular septal defects in which there is no separation between the left and right ventricle of the heart and are responsible for Holt-Oram syndrome.