59 A Clinical and Genetic Study of Newborns with Conotruncal Heart Diseases and Del22Q11.2 Syndrome

Abstract

Background/aims Congenital heart diseases (CHD) occur in 8 per 1000 births. ConoTruncal Heart Defects (CTHD) account for 50% of CHD. 22q11 deletion prevalence is high in patients with CTHD (16%). The most common CTHDs in del22q11 patients are Tetralogy of Fallot (ToF), Pulmonary Atresia + Ventricular Septal Defect (PA+VSD), Aortic Arch Interruption (AAI), Truncus arteriosus (TA).Patients and methods in 1999 a study to determine the prevalence of del22q11 in patients with CTHD, to describe the phenotypic variability and to analyse the familial occurrence of deletion, was designed. The parents of deleted probands were studied too. Caryotype from peripheral blood lymphocytes by fluorescent in situ hybridisation (FISH) using specific probe D22S75 was performed.Results Over a period of 5 years, 135 patients (M: 70, F: 65) with CTHD were enrolled.: 47 (35%) ToF, 39 (29%) Transposition of Great Arteries (TGA), 23 (17%) PA+VSD, 10 (7,5%) Double Outlet Right Ventricle (DORV), 7 (5%) TA, 3 (2%) AAI, 6 (4,4%) other CHDs. 27 (M: 12, F: 15) showed del22q11.2: 14 (30%) ToF, 8 (35%) PA+VSD, 1 (33%) AAI, 1 (14%) TA and 3 other types of CHD. In the familial cases with del22q11.2, we found: An affected father of a child without CTHD, a mother and her daughter with the same CHD, 2 unaffected mothers of affected probands. 26 deleted patients showed dysmorphic facial features (elongated face, micrognatia, hypertelorism, bulbous nose), 1 cleft-palate, 4 velopharyngeal insufficiency, 2 thymic hypo-/aplasia, 2 hypocalcemia, 1 reduced cell CD3+, 9 developmental and speech delay/behavioural problems.Conclusions Del22q11 frequency in patients with CTHD is high (20%) and higher in patients with CTHD and clinical features of del22q11 syndrome. The analysis of del22q11 should not be excluded: In patients with CTHD, including the newborns, and without characteristic fenotype; in parents of deleted children.