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Congenital heart defect in sibs with discordant karyotypes
M C Digilio1, B Marino, S A Canepa
1Department of Medical Genetics, Bambino Gesù Hospital, Rome, Italy.
Insights
Familial congenital heart defects (CHDs) occurred in siblings with different genetic conditions, including Down syndrome. This suggests shared genetic factors may influence both typical and atypical CHDs.
Area of Science:
- Genetics
- Cardiology
- Pediatrics
Background:
- Congenital heart defects (CHDs) exhibit significant genetic heterogeneity.
- Familial occurrence of CHDs in individuals with and without Down syndrome is uncommon.
Observation:
- Three families presented with concordant CHDs in siblings possessing discordant karyotypes.
- Specific CHDs like atrioventricular canal (AVC) and tetralogy of Fallot were observed across affected siblings.
Findings:
- One family showed atrioventricular canal (AVC) in both a chromosomally normal child and a sibling with Down syndrome (trisomy 21).
- Another family had AVC associated with trisomy 21 in one sibling and trisomy 18 in another.
- Tetralogy of Fallot was present in a sibling with Down syndrome and their non-syndromic sister.
Implications:
- These cases suggest a potential shared genetic susceptibility to both euploid and aneuploid CHDs.
- Common predisposing genetic factors might contribute to the development of CHDs in both syndromic and non-syndromic individuals.
- Further research into shared genetic pathways is warranted for understanding CHD etiology.
Abstract:
Congenital heart defects (CHDs) are genetically heterogeneous, associated with a variety of genetic conditions. Familial aggregation of CHD in patients with and without Down syndrome is rare. We report on the occurrence of concordant CHD in three sets of sibs with discordant karyotypes. In the first family, atrioventricular canal (AVC) was diagnosed in a chromosomally normal child and in his brother with Down syndrome. In the second family, AVC was associated with trisomy 21 in one sib and with trisomy 18 in the other. In the third family, tetralogy of Fallot was present in one patient with Down syndrome and in his nonsyndromic sister. Although the genetic heterogeneity of Down and non-Down CHD is not disputed, a susceptibility to both euploid and aneuploid CHDs could exist, and common predisposing factors could play a role in both conditions.