Thoracic Aneurysms of the Aorta ascendens with type A Dissection (TAAD) Gene Panel
Dr. rer. nat. Karin Mayer
Thoracic aneurysms of the aorta ascendens with type A dissection (TAAD) may occur isolated or due to a genetic syndrome. Hereditary connective tissue disorders that are associated with a high risk for TAAD are the classic Marfan syndrome (MFS), the Loeys-Dietz syndrome (LDS) and the vascular type of the Ehlers-Danlos syndrome (EDS type IV). About 10–20% of the isolated forms of TAAD are inherited in an autosomal dominant pattern with reduced penetrance and variable expression.
So far, nine gene loci for familial TAAD have been localized and seven genes have been identified: AAT3 on chromosome 3p24–25 (TGFBR2 gene), AAT4 on chromosome 16p13.13–p13.12 (MYH11 gene), AAT5 on chromosome 9q33–q34 (TGFBR1 gene), AAT6 on chromosome 10q22–24 (ACTA2 gene) and AAT7 on chromosome 3q21 (MYLK gene). For AAT1 on chromosome 11q23–24 and AAT2 on chromosome 5q13–14 no gene has been identified yet. In 2011 an eighth gene loci for TAAD was identified on chromosome 15q22.2–24.2 (SMAD3 gene) and in 2012 an additional gene was identified on chromosome 1q41 (TGFB2 gene). Since clinical distinction of the different types is often difficult, genetic diagnostics using next generation sequencing (NGS) can facilitate diagnosis.
All coding exons and their flanking intronic sequences from the genes in the TAAD gene panel are analyzed either by Sanger sequencing or by next generation sequencing (NGS).