Isolation of the subclavian artery associated with chromosome 22q11 deletion.

An interesting report on isolation of the subclavian artery appeared in the recent issue of this journal. The authors reported 3 patients with interruption of the aortic arch between the carotid arteries ('type B'), isolation of the subclavian artery, and deletion of the chromosome 22ql l . Isolation of the subclavian artery is a rare anomaly. Although the authors discussed only briefly the etiologic significance of isolation of the subclavian artery combined with chromosome 22qll , further discussion is warranted. In our early study on cardiovascular anomalies associated with tetralogy of Fallot and chromosome 22qll deletion, isolation of the subclavian artery was present in 3 out of 22 patients with the deletion, and in none of another 22 patients without the deletion. Isolation of the subclavian artery was present in another patient with deletion of the chromosome 22qll and a normal heart. This combination suggests that isolation of the subclavian artery is another of the specific features of chromosome 22qll deletion. Chromosome 22ql 1 deletion causes those cardiovascular anomalies which are related to insufficiency of embryonic neural crest cells. Neural crest cells are important in septation of the developing ventricular outflow tracts and arterial segments, and persistence and regression of arch arteries. Isolation of the subclavian artery associated with the chromosome 22qll deletion is another piece of evidence confirming the role of neural crest cells in development of the aortic arches. Kazuo Momma Professor ofPediatric Cardiology, The Heart Institute of Japan, Tokyo Women's Medical University, Tokyo, Japan