Osteogenesis imperfecta is a connective tissue disorder caused by genetic defects in type I collagen synthesis, and as such is a "close relative" of some Ehlers-Danlos types. This provides more evidence that type I collagen disorders have unexpected effects on cardiac abnormalities.

Osteogenesis imperfecta apparently puts patients at higher risk of cardiac abnormalities, say researchers from Norway.

Patients with osteogenesis imperfecta "should be followed up more closely, and the referral threshold to a cardiologist should be lower," said lead author Dr. Zoran Radunovic from Oslo University Hospital-Aker in email to Reuters Health.

The hereditary connective tissue disorder is caused by genetic defects in type I collagen synthesis. "We knew that the collagen rich tissues are affected in this group of patients and knew up to the certain level that both myocardium and valves are affected, but we were surprised at the prevalence of aortic and mitral regurgitation and increased dimensions of the left ventricle," Dr. Radunovic said.

Valvular dysfunction and aortic root dilatation had been linked to osteogenesis imperfecta in a few small studies. But Dr. Radunovic and his colleagues wanted to know more about the prevalence of cardiovascular abnormalities in a larger group cohort, so they compared echocardiography findings in 99 adult patients and 52 age- and gender-matched controls.

Systolic and diastolic blood pressures were significantly higher and body-surface area was significantly smaller among patients vs controls, according to their paper in the March American Heart Journal.

Also, interventricular septal wall thickness, left ventricular posterior wall thickness, left ventricular mass, and left ventricular relative wall thickness were significantly larger in the patients.

When indexed for body-surface area, all four aortic diameters measured were significantly larger in patients than in controls. Diameters were largest in the patients with type III osteogenesis imperfecta, the most severe form.

There was mild mitral regurgitation in both groups, but moderate mitral regurgitation and mild or moderate aortic regurgitation were present only in the patient group.

In a multivariate linear regression analysis, osteogenesis imperfecta and systolic blood pressure were the only significant predictors of left ventricular wall thickness and mass, whereas osteogenesis imperfecta was the only significant predictor of all four aortic diameters.

"We hope that the results of our study are going to draw the physician's attention and focus their interest not only on skeletal problems, which are well studied and known, but on the cardiovascular system as well," Dr. Radunovic said.

"We are missing a prospective study which could help us understand the development of the disease through the years," he added.

Am Heart J 2011;161:523-529. Abstract.

Will Boggs, MD • Reuters Health Information © 2011