LZTR1 and Noonan syndrome: Case 87: In a male with history of hypertrophic cardiomyopathy, short stature, developmental delay, and distinctive facies in keeping with Noonan syndrome, we detected increased usage of a 117 bp exon within intron 16 of the LZTR1 gene which is predicted to result in an in-frame insertion of 36 amino acids (NM_006767.4; Fig. 4A).