Severe dilative Cardiomyopathy in mucopolysaccharidosis type 1 (Hurler's Syndrome)

Introduction: A dilative cardiomyopathy (DCM) is rarely the first sign in an infant with Mucopolysaccharidosis type 1.

Case report: We report on an 8 month old boy admitted to hospital critically ill who had dys- and tachypnea. Echocardiography on admission showed a severe dilative cardiomyopathy (Left ventricular enddiastolic dimension LVEDd 43mm, fractional shortening FS 14%, aortic velocity time integral av-VTI 5–6cm). Anticongestive therapy improved the infant's clinical condition rapidly, while echocardiographic parameters remained constant.

Repeated history taking revealed a failure to thrive since 4th month and a general delayed motor development since 5th month and loss of motor skills since 7th month of age. The infant showed a slightly coarse facies and corneal clouding.

The results of the metabolic tests were pending at the time of transfer to the Children's Heart Center for invasive diagnostic procedures and prelisting for heart transplant. A significant increase of glycosaminoglycans (GAGs) in urine proved metabolic DCM. The result of decreased activity of alpha-L-iduronidasis in leucocytes was conclusive for the diagnosis of mucopolysaccharidosis type I (Hurler's Syndrome). Enzyme replacement therapy (ERT) with intravenous laronidase was started immediately. Allogenic stem cell transplantation is recommended as soon as possible in every Hurler's patient but stabilization of cardiac function has to be warranted.

Conclusion: Inborn errors of metabolism should be considered in all cases of DCM. DCM due to Hurler's syndrome without valvular involvement can occur as GAGs accumulate in the myocardium and myointima of coronary arteries.