[The 22q11.2 deletion syndrome: immunological questions].

The 22q11.2 deletion syndrome occurs in approximately 1 of 3000-5000 children. This is a congenital disorder characterized by facial dysmorphic features, cardiac defects, thymic hypoplasia, cleft palate, hypoparathyroidism, and psychiatric disorders. Patients generally exhibit a mild to moderate decrement in T-cell numbers with preservation of T-cell function. We describe advances in understanding the genetic basis of this syndrome, its clinical manifestations, and new information on immunodeficiences in this syndrome.