Surgical treatment of marked mitral valvar deformity combined with I-cell disease 'Mucolipidosis II'.

I-cell disease is a rare, hereditary, and fatal disease, which is often complicated with disease of the cardiac valves. We have experienced a case of severe mitral valvar insufficiency in a 9-month-old male infant with I-cell disease. Mitral valvoplasty was difficult, because the leaflets were remarkably hypertrophic, and the tendinous cords were elongated and adherent. Despite these difficulties, surgery proved effective in the treatment of the congestive heart failure, allowing for further treatment of the I-cell disease.