Prevalence and parental origin in Tetralogy of Fallot associated with chromosome 22q11 microdeletion.
OBJECTIVE
Tetralogy of Fallot is a common cardiac anomaly that is associated with chromosome 22q11 microdeletion. In this study we examined the mode of transmission as well as the parental origin of microdeletion in patients with tetralogy of Fallot.


METHODS
Eighty-four children with sporadic tetralogy of Fallot (40 boys and 44 girls; mean age, 34 months) were analyzed for microdeletion at chromosome 22q11 by genotype analysis, using five microsatellite markers, D22S427, D22S941, D22S944, D22S264 and D22S311, and confirmed by quantitative polymerase chain reaction, using TUPLE1 and D22S264. All parents of these subjects consented to their own participation and their child's participation in the clinical evaluation and molecular study. To provide a molecular characterization of microdeletion, we isolated DNA from the parents and typed their DNA with each of the five polymorphic markers.


RESULTS
Sixty-six patients were associated with pulmonary stenosis; and 8 of these cases (12%) had microdeletion. Eighteen patients were associated with pulmonary atresia, and 6 (33%) of these cases had microdeletion. The parental origins of the 14 patients with microdeletion were paternal in 3 cases and maternal in 11 cases. The most common mode of transmission was de novo without parental hemizygosity (93%). Transmission by autosomal dominant heredity was uncommon (7%).


CONCLUSIONS
Biased parental origin was consistently found in tetralogy of Fallot patients with chromosomal 22q11 microdeletion. Our results indicated a higher prevalence of microdeletion because of inheritance of maternal microdeletion (78%).
Lu
J H
JH
Department of Pediatrics, Veterans General Hospital-Taipei, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Chung
M Y
MY
Hwang
B
B
Chien
H P
HP
D000015:Abnormalities, Multiple; D000328:Adult; D002675:Child, Preschool; D002892:Chromosomes, Human, Pair 22; D005220:Fathers; D005260:Female; D017353:Gene Deletion; D006801:Humans; D019656:Loss of Heterozygosity; D008297:Male; D018895:Microsatellite Repeats; D009035:Mothers; D015995:Prevalence; D013577:Syndrome; D013771:Tetralogy of Fallot / Q000453:epidemiology* / Q000235:genetics*