REDUCED PENETRANCE AND VARIABLE EXPRESSIVITY OF FAMILIAL THORACIC AORTIC ANEURYSMS DISSECTIONS/

Autosomal dominant inheritance of thoracic aortic aneurysms and dissec tions occurs in subjects with Marfan syndrome, which results from muta tions in the FBN1 gene on chromosome 15. A second chromosomal locus on 3p24-25 has been identified for a Marfan-like condition with thoracic aortic aneurysms. We describe here 6 families with multiple members w ith thoracic aortic aneurysms and dissections in the absence of the oc ular and skeletal complications of Marfan syndrome. Medical records an d autopsy reports on affected subjects in families with multiple membe rs with thoracic aortic aneurysms and dissections were reviewed. Subje cts in these Families at risk for developing aortic disease underwent echocardiography to evaluate the aorta. The pattern of inheritance of thoracic aortic aneurysms and dissections was autosomal dominant in th ese families. Most affected subjects presented with aortic root dilata tion or acute type I dissection, but the age of onset of: disease was variable and there was decreased penetrance of the disorder. In 2 of t he families, the syndrome was not linked to FBN1 or 3p24-25. Familial thoracic aortic aneurysm and dissection is an autosomal dominant condi tion with marked variability in the age oi: onset of aortic disease an d decreased penetrance, making identification of affected subjects dif ficult. This condition is not due to mutations in the FBN1 gene or the unidentified gene ore 3p24-25. (C) 1998 by Excerpta Medica, Inc.