holt-oram syndrome

Holt-Oram syndrome, also known as heart-hand syndrome, is an autosomal dominant disorder, with complete penetrance and very variable expression, and a prevalence of 1 in 100,000 live births (24).

 

The syndrome is characterized by cardiac anomalies in fetuses with upper limb deformities.

Preaxial radial ray malformations occur in all affected fetuses and is required for the diagnosis.

Cardiac anomalies are present in 85% to 95% of cases.

Secundum atrial septal defects and muscular ventricular septal defects are the most common cardiac lesions (25). Conduction defects occur in 40% of cases.

Mutations in the gene TBX5 on the chromosome locus 12q24.1 have been identified in cases with Holt-Oram syndrome (24). De novo mutations occur in 30% to 40% of cases.

The absence of a detected TBX5 mutation does not preclude the diagnosis. Table 2-6 is a comprehensive list of nonnumerical chromosomal disorders and their association with congenital heart defects, and Table 2-7 is a list of genes known to be associated with congenital heart defects.