A heart defect that allows blood to pass from the right side of the heart directly to the left, bypassing the lungs. There is considerable heterogeneity with several loci implicated. AVSD1 is associated with a locus on chromosome 1, AVSD2 is caused by a mutation in CRELD1 (cysteine-rich with EGF-like domain protein 1, 420 aa). Other forms are associated with mutations in connexin 43 (heart connexin) and with Down's syndrome.
Subjects: Medicine and Health.