Trisomy 8 mosaicism in a patient with heterotaxia

Abstract

Constitutional trisomy 8 mosaicism (CT8M) is a relatively rare trisomy in humans with a characteristic phenotype. We report an infant with the characteristic CT8M phenotype in addition to heterotaxia. A number of chromosomal abnormalities have been reported in association with laterality defects but this is the first time heterotaxia is reported in CT8M. In addition to expanding CT8M phenotype, our report may provide insight into the mechanism of heterotaxia.

Investigation of Genetic Causes in Patients with Congenital Heart Disease in Qatar: Findings from the Sidra Cardiac Registry

“…Although discussion of the cardiac phenotype of mosaic trisomy 8 is limited due to a paucity of published data, cardiovascular [ 33 ], laterality [ 34 ], and septal [ 35 ] defects have been reported in several cases. Mosaic trisomy 14 is another chromosomal aberration that was observed in a patient with syndromic CHD (cardio-28.A); it is typically associated with cardiac defects [ 36 ], such as patent ductus arteriosus [ 37 ], and TOF [ 38 , 39 ].…”

Constitutional Trisomy 8 Mosaicism with Persistent Macrocytosis

“…This could hypothetically be explained by the following 2 scenarios: tissue-specific mosaicism and uniparental disomy (UPD). It has been proposed that in some cells the loss of the extra copy of chromosome 8 could lead to mo- saicism [Habecker-Green et al, 1998;Nucaro et al, 2003;Alkuraya and Harris, 2005]. In contrast, 2 candidate genes ( KCNK9 : oncogene , DLGAP2 : tumor suppressor) on chromosome 8 may be related to UPD [Luedi et al, 2007].…”

“…Although CT8M is compatible with life, it has extremely variable phenotypes ranging from normal features to severe malformations [Alkuraya and Harris, 2005;Agrawal and Agrawal, 2011]. Complete trisomy 8 is thought to result from meiotic nondisjunction, whereas CT8M is thought to result from a post-zygotic event [Karadima et al, 1998;Alkuraya and Harris, 2005].…”