MYOPATHOLOGY IN PATIENTS WITH A NOONAN PHENOTYPE

Two patients with a Noonan phenotype and progressive hypertrophic obst ructive cardiomyopathy are described, in whom abnormal histopathologic al changes in striated musculature were detected. In both patients an increased density of muscle spindles was found at biopsy. The signific ance of an increased density of muscle spindles in patients with Noona n phenotype can only be speculated. The question is raised of whether these changes are a distinct feature within the spectrum of patients w ith Noonan phenotype.