Possible association between the hernia of Morgagni and trisomy 21.

Of the 5 liveborn infants with the hernia of Morgagni recorded in the California Birth Defects Monitoring Program, 3 had trisomy 21. This significant association (P < 10(-6)) between the hernia of Morgagni and trisomy 21 may reflect defective dorsoventral migration of rhabdomyoblasts from the paraxial myotomes, caused by increased cellular adhesiveness in trisomy 21.