Neural tube defects and deletions of 22q11.

Recently we reported on three unrelated children with neural tube defects (NTDs) and deletion of 22q11. Two of these children have velo-cardio-facial syndrome and the third DiGeorge sequence. Thus, NTDs appear to be part of the clinical picture due to 22q11 deletion. To further explore this association and to clarify what findings should prompt testing for this deletion in individuals with NTDs, we have reviewed all patients in a large regional spina bifida clinic population. Two hundred ninety-five patients with NTDs were identified by chart review. Charts were reviewed for congenital heart defect, minor facial anomalies, thymic hypoplasia, cleft lip and/or palate, hypocalcemia, and a family history of a NTD, congenital heart defect, or cleft lip and/or palate. A total of 22 patients was identified with NTD and at least one more clinical trait and/or a positive family history. Sixteen children received cytogenetic and molecular testing including the three previously reported patients diagnosed with a 22q11 deletion. Results of cytogenetic and molecular studies of the remaining 13 patients were normal. Deletion of 22q11 is an infrequent cause of NTDs. We recommend testing for the 22q11 deletion in patients with a NTD and conotruncal heart defect. Testing should be considered in patients with a NTD who have a first degree relative with a conotruncal heart defect or have additional clinical findings of VCFS or DGS.