Consanguinity and pattern of congenital heart defects in Down syndrome in Kashmir, India

Objective of our study was to ascertain the relation of consanguinity to Down syndrome (DS), and pattern of congenital heart defects (CHD) in DS. Setting: Department of Pediatrics, G B Pant Hospital, an associated hospital of Govt Medical College Srinagar. It was designed as a case control study. Fifty phenotypically DS patients aged between 0-12 years, attended our hospital from September 2007 to August 2008, were selected, formed the cases (Group I), and an equal number of patients, comparable in all respects but with-out DS or other apparent congenital malformations, were kept as controls (Group II). After detailed history and thorough examination, patients were enquired about the familial ties, and traditional values and a three generation pedigree was generated to ascertain consanguinity. All patients under-went echocardiography in addition to routine laboratory tests. The chi-square test was used to compare the proportions. Males constituted 27 and 26, while as females constituted 23 and 24 in group I and II respectively (p-value=0.841). Frequency of CHD among group I and II was 25(50%) and 15 (30%) respectively (p-value=0.041, OR=2.3). Pattern of CHD showed atrio-ventricular canal defects (AV canal defects) in 7 (28%) in group I, and nil among group II (p-value=0.024, OR=11.7), while as the commonest CHD in both groups was VSD. Among the group I consanguinity was present in 14 (28%), while in group II consanguinity was present 17 (34%) (p-value=0.51, OR=0.75). However, in group I with CHD, consanguinity was observed in 14 (56%), and in group II with CHD consanguinity was observed in 3(20%) patients (p-value 0.001, OR 9.3). Fifteen (60%) cases among the group I and 4 (26.7%) cases among the group II were females with CHD (p-value=0.041, OR=4.1).CHD is more common and severe among DS children who are products of consanguineous marriage, and CHD is more frequently seen in female DS children.