Findings of hypertelorism (widely spaced eyes), bifid or split uvula, and skin findings such as easy bruising or abnormal scars may distinguish Loeys–Dietz from Marfan syndrome.Affected individuals often develop immune system related problems such as allergies to food, asthma, hay fever, and inflammatory disorders such as eczema or inflammatory bowel disease.Findings of Loeys–Dietz syndrome may include:
Skeletal/spinal malformations: craniosynostosis, Scoliosis, spinal instability and spondylolisthesis, Kyphosis
Sternal abnormalities: pectus excavatum, pectus carinatum
Contractures of fingers and toes (camptodactyly)
Long fingers and lax joints
Weakened or missing eye muscles (strabismus)
Club foot
Premature fusion of the skull bones (craniosynostosis)
Joint hypermobility
Congenital heart problems including patent ductus arteriosus (connection between the aorta and the lung circulation) and atrial septal defect (connection between heart chambers)
Translucency of the skin with velvety texture
Abnormal junction of the brain and medulla (Arnold–Chiari malformation)
Bicuspid aortic valves
Criss-crossed pulmonary arteries

Cause
Types (old nomenclature)
Several genetic causes of Loeys–Dietz syndrome have been identified. A de novo mutation in TGFB3, a ligand of the TGF β pathway, was identified in an individual with a syndrome presenting partially overlapping symptoms with Marfan Syndrome and Loeys–Dietz Syndrome. Diagnosis
Diagnosis involves consideration of physical features and genetic testing. Presence of split uvula is a differentiating characteristic from Marfan Syndrome, as well as the severity of the heart defects. Loeys–Dietz Syndrome patients have more severe heart involvement and it is advised that they be treated for enlarged aorta earlier due to the increased risk of early rupture in Loeys–Dietz patients.
In other cases it is inherited from one affected parent.Loeys–Dietz syndrome was identified and characterized by pediatric geneticists Bart Loeys and Harry "Hal" Dietz at Johns Hopkins University in 2005. Signs and symptoms
There is considerable variability in the phenotype of Loeys–Dietz syndrome, from mild features to severe systemic abnormalities. The primary manifestations of Loeys–Dietz syndrome are arterial tortuosity (winding course of blood vessels), widely spaced eyes (hypertelorism), wide or split uvula, and aneurysms at the aortic root. Other features may include cleft palate and a blue/gray appearance of the white of the eyes. Cardiac defects and club foot may be noted at birth.There is overlap in the manifestations of Loeys–Dietz and Marfan syndromes, including increased risk of ascending aortic aneurysm and aortic dissection, abnormally long limbs and fingers, and dural ectasia (a gradual stretching and weakening of the dura mater that can cause abdominal and leg pain).